{"success":true,"data":{"pressRelease":{"id":"158575","rtpr_id":"nGNX6dy7x7-20261001","ticker":"REGN","exchange":"NASDAQ","all_tickers":["REGN"],"title":"Ubamatamab (MUC16xCD3) Shows a High Rate of Durable Responses in Initial Study of Patients with Advanced Low-Grade Serous Ovarian Cancer (LGSOC)","author":"Globe Newswire","published_at":"2026-10-01T15:35:00.144Z","article_body":"LGSOC is a biologically distinct variant of ovarian cancer, with limited\ntreatment options, that is generally less responsive to conventional\nchemotherapy\n\nResults presented in a late-breaking plenary session at IGCS demonstrated a\n73% objective response rate and 11-month median progression-free survival in\n11 patients with recurrent and heavily pre-treated LGSOC treated with the\nhighest dose of ubamatamab in the trial  \n\nRegeneron has been enrolling a dedicated LGSOC cohort at this dose and will\nadvance ubamatamab into a confirmatory Phase 3 trial of this lethal cancer\nwith limited treatment options\n\nTARRYTOWN, N.Y., Oct. 01, 2026 (GLOBE NEWSWIRE) -- Regeneron Pharmaceuticals,\nInc. (NASDAQ: REGN) today announced the first results for the investigational\nubamatamab in patients with low-grade serous ovarian cancer (LGSOC). The data\nare from an ongoing Phase 1/2 trial in recurrent platinum-resistant high- or\nlow-grade serous ovarian cancer that were presented in a late-breaking plenary\noral session at the International Gynecologic Cancer Society (IGCS) 2026\nAnnual Global Meeting. Ubamatamab is a MUC16xCD3 bispecific antibody designed\nto bridge MUC16 on cancer cells with CD3-expressing T cells to facilitate\nlocal T-cell activation. Based on these preliminary trial results, Regeneron\nhas been enrolling a single-arm, potentially registrational LGSOC trial and\nwill be discussing the data with the U.S. Food and Drug Administration (FDA)\nin the coming months. Regeneron is also planning to initiate a confirmatory,\nrandomized, controlled Phase 3 trial to support the use of ubamatamab in\nLGSOC.\n\nLGSOC is a biologically distinct variant from the more common high-grade\nserous ovarian cancer (HGSOC), comprising up to 10% of serous ovarian cancer,\nwith typically uniformly high MUC16 expression and limited treatment options.\nThe disease often affects younger women and is characterized by slower-growing\ntumors than those seen in HGSOC, but frequently recurs and is less responsive\nto conventional chemotherapy with few treatment options. LGSOC has a median\noverall survival of approximately seven years from initial diagnosis, compared\nto approximately four years for HGSOC. In recurrent advanced LGSOC, historical\ntrial data have shown that objective response rates (ORRs) generally remain\nbelow 15% with chemotherapy and endocrine therapy, while the only approved\ntherapy has an ORR of 44% in biomarker-selected patient populations\n(representing about 30% of the overall LGSOC population).\n\n“The high rate of durable responses observed thus far with ubamatamab in\nlow-grade serous ovarian cancer, without requiring biomarker selection, are\nhighly encouraging and reinforce our excitement about MUC16 as a new\ntherapeutic target in this difficult-to-treat disease,” said Israel Lowy,\nM.D., Ph.D., Clinical Development Unit Head, Oncology, at Regeneron. “This\ninitial clinical evidence highlights the potential of our bispecific approach\nto bring a differentiated and first-in-class treatment option to patients in\nneed. We are pleased with the safety profile of the drug as well, and are\neager to build on these findings through our ongoing trial and planned\nconfirmatory Phase 3 trial.”\n\nData presented at IGCS focused on the LGSOC subset of 19 patients who had\nreceived a median of four prior lines of therapy and were dosed with\nintravenous ubamatamab ranging from 3 to 800 mg weekly or every three weeks.\nUbamatamab was given either as monotherapy or in combination with Libtayo(®\n)(cemiplimab).\n\nIncluded in the presentation were 11 patients treated with 800 mg of\nubamatamab monotherapy, eight treated weekly and three treated every three\nweeks. Results at the 800 mg doses showed a:\n* 73% ORR (95% Confidence Interval [CI]: 39.0 to 94.0), with all responses\nbeing partial responses\n* 9-month median duration of response (95% CI: 6.9 to not estimable [NE]), per\nKaplan-Meier estimate\n* 11-month median progression-free survival (95% CI: 3.0 to NE), per\nKaplan-Meier estimate\nSafety was assessed across all 19 patients in the LGSOC subset.\nTreatment-emergent adverse events (TEAEs) occurred in 100% of participants\n(n=19). Cytokine release syndrome occurred in 90% of participants (n=17), all\nof which were Grade 1 or 2. Serious TEAEs grade 3 or higher occurred in 21%\n(n=4) of participants and treatment-related adverse events (TRAEs) occurred in\n74% of participants (n=14). Grade 3 or higher TRAEs included neutropenia (21%;\nn=4), anemia (11%; n=2), increased alanine aminotransferase (11%; n=2),\nincreased aspartate aminotransferase (11%; n=2), abdominal pain (5%; n=1) and\nileus (5%; n=1). Most adverse events occurred during the step-up dosing\nperiod. One participant discontinued treatment due to a stroke considered\nunrelated to ubamatamab treatment; no TEAEs resulted in death.\n\nThe potential uses of ubamatamab described above are investigational, and its\nsafety and efficacy have not been evaluated by any regulatory authority.\n\nAbout the Trial\nThe ongoing, open-label, Phase 1/2 trial is evaluating ubamatamab alone and in\ncombination with Libtayo in adult patients with recurrent platinum-resistant\novarian cancer and other recurrent MUC16-expressing cancers.\n\nThe Phase 1 portion of the trial is primarily assessing safety, tolerability,\ndose-limiting toxicities and pharmacokinetics of ubamatamab, with efficacy\nevaluated as a secondary endpoint through measures such as ORR, duration of\nresponse and progression-free survival. The Phase 2 portion is evaluating the\nanti-tumor activity of ubamatamab, primarily through ORR, while continuing to\nassess safety and tolerability.\n\nA prospective, dedicated, potentially registrational cohort in the Phase 2\nportion of this trial is evaluating ubamatamab 800 mg monotherapy every three\nweeks in up to 100 patients with recurrent LGSOC and is currently enrolling.\nIf you are interested in learning more about this trial, please contact us\n(clinicaltrials@regeneron.com, +1 844 734 6643), or visit our clinical\ntrial website\n(https://www.globenewswire.com/Tracker?data=9edXPlzWP7w_G9B-WxsxzIuxzbmiwPDEJoVcFruPOSsR2iBBx0km3fz6kiCQd3jcVBzfFfd8lLjXeF6F93tIYy_6mEltUP4Nxt0_vxUSmqJzgdOkp1CfEr8lpCH-I6HsnFdQMjGHAAfek7SODM4bp85G42I67Hjrsn1uvBxzxhNhMViIXXU1q9k78a0Xbw0vo1ssqYzZZQJTFdUlraBHVg==).\n\nAbout Ovarian Cancer\nOvarian cancer is one of the most common gynecologic cancers and remains a\nleading cause of cancer-related mortality among women. It arises from the\nuncontrolled growth of abnormal cells in the ovary and is frequently diagnosed\nat an advanced stage, when disease has spread beyond the ovary. In 2026, an\nestimated 21,010 new cases of ovarian cancer were expected to be diagnosed in\nthe U.S., and approximately 12,450 women were expected to die from the\ndisease. Despite advances in treatment, ovarian cancer remains a significant\nunmet medical need, with many patients ultimately experiencing disease\nrecurrence and progression. \n\nLGSOC is a distinct form of ovarian cancer that occurs in younger women and\ncomprises up to 10% of new epithelial ovarian cancer cases. While LGSOC tumor\ncells tend to grow and divide more slowly than those seen in high-grade serous\novarian cancer, the disease frequently recurs and is less responsive to\nconventional chemotherapy. LGSOC has a median overall survival of\napproximately seven years from initial diagnosis, compared to approximately\nfour years for HGSOC. Although endocrine therapy and targeted therapies are\nused in selected patients, treatment options remain limited for many people\nwith recurrent disease.\n\nAbout Regeneron in Cancer\nWe aspire to turn revolutionary discoveries into medicines that can transform\nthe lives of those impacted by cancer. Our team around the world is driven to\nsolve the needs and challenges of those affected by one of the most serious\ndiseases of our time.\n\nBacked by our legacy of scientific innovation and a deep understanding of\nbiology, genetics and the immune system, we’re pursuing potential therapies\nacross more than 30 types of solid tumors and blood cancers. Our cancer\nstrategy is powered by cutting-edge technologies and therapies that can be\nflexibly combined to investigate potentially transformative treatments for\npatients. Oncology assets in clinical development comprise nearly half of\nRegeneron’s pipeline, and include checkpoint inhibitors, bispecific\nantibodies and costimulatory bispecific antibodies. Our approved PD-1\ninhibitor Libtayo serves as the backbone of many of our investigational\ncombinations. To complement our extensive in-house capabilities, we\ncollaborate with patients, healthcare providers, governments, biopharma\ncompanies and each other to further our shared goals. Together, we are united\nin the mission to serve as a beacon of transformation in cancer care.\n\nAbout Libtayo    \nLibtayo is a fully human monoclonal antibody targeting the immune checkpoint\nreceptor PD-1 on T cells and was invented using Regeneron's\nproprietary VelocImmune(®) technology. By binding to\nPD-1, Libtayo has been shown to block cancer cells from using the PD-1\npathway to suppress T-cell activation. Libtayo has been approved by\nregulatory authorities in more than 30 countries in one or more indications,\nincluding for certain adult patients with advanced basal cell carcinoma (BCC),\nadvanced cutaneous squamous cell carcinoma (CSCC), advanced NSCLC and\nadvanced cervical cancer.  \n\nIn the U.S., the generic name for Libtayo in its approved indications\nis cemiplimab-rwlc, with rwlc as the suffix designated in accordance\nwith Nonproprietary Naming of Biological Products Guidance for Industry\nissued by the U.S. FDA. Outside of the U.S., the generic name\nof Libtayo in its approved indications is cemiplimab.   \n\nThe extensive clinical program for Libtayo is focused on\ndifficult-to-treat cancers. Libtayo is currently being investigated in\ntrials as a monotherapy, as well as in combination with either conventional or\nnovel therapeutic approaches for other solid tumors. These potential uses\nare investigational, and their safety and efficacy have not been evaluated by\nany regulatory authority.     \n\nWhat is the most important information I should know about LIBTAYO?  \nLIBTAYO is a medicine that may treat certain cancers by working with your\nimmune system. LIBTAYO can cause your immune system to attack normal organs\nand tissues in any area of your body and can affect the way they work. These\nproblems can sometimes become severe or life-threatening and can lead to\ndeath. You can have more than one of these problems at the same time. These\nproblems may happen anytime during treatment or even after your treatment has\nended. \n\nCall or see your healthcare provider right away if you develop any new or\nworsening signs or symptoms, including:  \n* Lung problems: cough, shortness of breath, or chest pain  \n*\nIntestinal problems: diarrhea (loose stools) or more frequent bowel movements than\nusual, stools that are black, tarry, sticky or have blood or mucus, or severe\nstomach-area (abdomen) pain or tenderness  \n* Liver problems: yellowing of your skin or the whites of your\neyes,\nsevere nausea or vomiting, pain on the right side of your stomach-area\n(abdomen), dark urine (tea colored), or bleeding or bruising more easily than\nnormal  \n* Hormone gland problems: headache that will not go away or unusual\nheadaches, eye sensitivity to light, eye problems, rapid heartbeat, increased\nsweating, extreme tiredness, weight gain or weight loss, feeling more hungry\nor thirsty than usual, urinating more often than usual, hair loss, feeling\ncold, constipation, your voice gets deeper, dizziness or fainting, or changes\nin mood or behavior, such as decreased sex drive, irritability,\nor forgetfulness  \n* Kidney problems: decrease in your amount of urine, blood in your urine,\nswelling of your ankles, or loss of appetite  \n* Skin problems: rash, itching, skin blistering or peeling, painful sores or\nulcers in mouth or nose, throat, or genital area, fever or flu-like\nsymptoms, or swollen lymph nodes  \n* Problems can also happen in other organs and tissues. These are not all\nof the signs and symptoms of immune system problems that can happen with\nLIBTAYO. Call or see your healthcare provider right away for any new or\nworsening signs or symptoms, which may include: chest pain, irregular\nheartbeat, shortness of breath or swelling of ankles, confusion, sleepiness,\nmemory problems, changes in mood or behavior, stiff neck, balance problems,\ntingling or numbness of the arms or legs, double vision, blurry vision,\nsensitivity to light, eye pain, changes in eyesight, persistent or severe\nmuscle pain or weakness, muscle cramps, low red blood cells, or bruising  \n* Infusion reactions that can sometimes be severe or life-threatening. Signs\nand symptoms of infusion reactions may include: nausea, vomiting, chills\nor shaking, itching or rash, flushing, shortness of breath or wheezing,\ndizziness, feel like passing out, fever, back or neck pain,\nor facial swelling  \n* Rejection of a transplanted organ or tissue. Your healthcare provider\nshould tell you what signs and symptoms you should report and monitor you,\ndepending on the type of organ or tissue transplant that you have had  \n* Complications, including graft-versus-host disease (GVHD), in people who\nhave received a bone marrow (stem cell) transplant that uses donor stem cells\n(allogeneic). These complications can be serious and can lead to death.\nThese complications may happen if you underwent transplantation either before\nor after being treated with LIBTAYO. Your healthcare provider\nwill monitor you for these complications  \nGetting medical treatment right away may help keep these problems from\nbecoming more serious. Your healthcare provider will check you for these\nproblems during your treatment with LIBTAYO. Your healthcare provider may\ntreat you with corticosteroid or hormone replacement medicines. Your\nhealthcare provider may also need to delay or completely stop treatment with\nLIBTAYO if you have severe side effects.  \n  \nBefore you receive LIBTAYO, tell your healthcare provider about all your\nmedical conditions, including if you:  \n* have immune system problems such as Crohn’s disease, ulcerative colitis,\nor lupus  \n* have received an organ or tissue transplant, including corneal\ntransplant   \n* have received or plan to receive a stem cell transplant that uses donor stem\ncells (allogeneic)  \n* have received radiation treatment to your chest area  \n* have a condition that affects your nervous system, such as myasthenia gravis\nor Guillain-Barré syndrome  \n* are pregnant or plan to become pregnant. LIBTAYO can harm your\nunborn baby  \nFemales who are able to become pregnant:  \n* Your healthcare provider will give you a pregnancy test before you\nstart treatment  \n*\nYou should use an effective method of birth control during your treatment and for at least 4\nmonths after your last dose of LIBTAYO. Talk to your healthcare provider about\nbirth control methods that you can use during this time  \n* Tell your healthcare provider right away if you become pregnant or think\nyou may be pregnant during treatment with LIBTAYO  \n* are breastfeeding or plan to breastfeed. It is not known if LIBTAYO passes\ninto your breast milk.\nDo not breastfeed during treatment and for at\nleast 4 months after the last dose of LIBTAYO  \n Tell your healthcare provider about all the medicines you take, including\nprescription and over- the-counter medicines, vitamins, and herbal\nsupplements.  \n  \nThe most common side effects of LIBTAYO when used alone to treat CSCC that has\nspread or cannot be cured by surgery or radiation, BCC, or NSCLC include\ntiredness, muscle or bone pain, rash, diarrhea, and low levels of red blood\ncells (anemia). The most common side effects of LIBTAYO when used alone to\nhelp prevent CSCC from coming back include rash and itching. The most common\nside effects of LIBTAYO when used in combination with platinum-containing\nchemotherapy to treat NSCLC include hair loss, muscle or bone pain, nausea,\ntiredness, numbness, pain, tingling, or burning in your hands or feet, and\ndecreased appetite.  \n  \nThese are not all the possible side effects of LIBTAYO. Call your doctor for\nmedical advice about side effects. You may report side effects to FDA at\n1-800-FDA-1088. You may also report side effects to Regeneron\nPharmaceuticals at 1-877-542-8296.  \n  \nPlease see full Prescribing Information\n(https://www.globenewswire.com/Tracker?data=eDkQQma1HFJyvFGQMU3EYvBJA6XFp5BssWPVZpYdTqsZeFXVRTDDRQ3_4fhVXw8RtdBEv5rKYmDAEM6frhLnE06iiWhjLIrt-P2L5RFXQRT8ggSssvvpI9w1Dgjui3vbzmR9wAu9A01cQcuGOCweBQ==),\nincluding Medication Guide\n(https://www.globenewswire.com/Tracker?data=iYEPA0BNy5s793TutKKR83BoVkQiIC8ali-tWC-qp8Mxrwlq6hO1bT7LXi_6hDi-of-IUqRGpx5-tr31GXEdKkB4r4nuCugWxqlO5ccED-qaHJUd0JvWtNeKjtDo_wYUghPRUtlMsH17_Brrety4GA==).  \n\nAbout Regeneron's VelocImmune(®) Technology\nRegeneron's VelocImmune technology utilizes a proprietary genetically\nengineered mouse platform endowed with a genetically humanized immune system\nto produce optimized fully human antibodies. When Regeneron's co-Founder,\nPresident and Chief Scientific Officer George D. Yancopoulos was a graduate\nstudent with his mentor Frederick W. Alt in 1985, they were the first to\nenvision\n(https://www.globenewswire.com/Tracker?data=TT4yTOIA8lKzyANkEWYAxSwh1uu1HlYK6jZETn_v4Yab9cprlErKs-LW2rS1fXuRL2SHIQKzuHg6H3PKw8aSZUXGR7SS_y47_NduEJCXKZZoAO86Ysi4VDxqJHTu_WEvM5RId-Ml0h0VyfqQENHE-dm5mWAf6Q8CLBTErxiV-Vq8hSItgwwfQZAxmCvlc2Yo1euMRltPCe2j5CYAK4HHHvZGwP9JE5RBIzcSQfOEXRR750w6bEqYWLeS6NblEQy0I7z5H6DGX97CYTdIaqksOjIjjlKGARJPAx2ufIL-mFPLVKyXxZTPXK-GmWuUcM8fOjD_Js6CAU1M2Tgj70COzsb16c_OF1jHYeR6d_vUhAzvvUXe3OimN4AUmA7uSy_cZqU-LqlFQZnXXk7hj5hNEbLYqTS7fRbeLIWdkHKe0svLOoa4PE-09K0pJCr7xrsqPBXuSFmF6BUWNzNDKr57qhx9AZjtSHJerHKUqk8NxgVLMqtM2Gw1iAuvSr6qemUxhsxR8Iv--tnz6byLi-_r83dVrdkZXGp2EFEFbWWq6AuIJM3284OESA2sQuIMSYsa-csmHim0mSLGfvgt5voBnTYDcf7unSYXwOCTD_td4_PQJRnFUHLXqhmZsvSwYwR4SuU_d7b90YwxUBdwd3M2SzajRYJB7S6sesibDWx8-8-10pufXs0P6gmNmDfSrR8gOhTB9zJb_LNDMCaB3Au-BbzhIx7RYH4rKT98JJm8akMtbdgeho43uB7j67qH8YjeQn06nWwPSh0-KPTE18awEb8MNBQh6W7xo8vKvaQ34JiOrSuInBKlBweR-OziueYg_h3YEHxFUTGYMZ6Kx3_dy2eJkopu3MZnwP4hUnCaeFiPILHmnuJUZBax24CwakQK4L-lGmY-u6ewg-jn39hAAYmv5mXxyDW9Ch37i24ktzVMR6LKa3K1JYvl1ZIjnlOdl8YmHdP_jIHTwpfORI8t3dpaX0xJ_wDbVlB0MkzFBy5lTTJclvrkhok6c-NG1nMvo2G7vs2tELEnji3-Wuem5w==)\nmaking such a genetically humanized mouse, and Regeneron has spent decades\ninventing and developing VelocImmune and related VelociSuite(®) technologies.\nDr. Yancopoulos and his team have used VelocImmune technology to create a\nsubstantial proportion of all original, FDA-approved fully human monoclonal\nantibodies. This includes Dupixent(®) (dupilumab), Libtayo(®\n)(cemiplimab-rwlc), Praluent(®) (alirocumab), Kevzara(®), Evkeeza(®)\n(evinacumab-dgnb), Inmazeb(®) (atoltivimab, maftivimab and odesivimab-ebgn),\nVeopoz(®) (pozelimab-bbfg) and Pasatru™ (garetosmab-grts). In addition,\nREGEN-COV(®) (casirivimab and imdevimab) had been authorized by the FDA\nduring the COVID-19 pandemic until 2024. A total of 11 antibody and bispecific\nproducts have been approved or authorized worldwide that were invented or\nderived using VelocImmune technologies.\n\nAbout Regeneron \nRegeneron (NASDAQ: REGN) is a leading biotechnology company that invents,\ndevelops and commercializes life-transforming medicines for people with\nserious diseases. Founded and led by physician-scientists, our unique ability\nto repeatedly and consistently translate science into medicine has led to\nnumerous approved treatments and product candidates in development, most of\nwhich were homegrown in our laboratories. Our medicines and pipeline are\ndesigned to help patients with eye diseases, allergic and inflammatory\ndiseases, cancer, cardiovascular and metabolic diseases, neurological\ndiseases, hematologic conditions, infectious diseases, and rare diseases.\n\nRegeneron pushes the boundaries of scientific discovery and accelerates drug\ndevelopment using our proprietary technologies, such as VelociSuite(®), which\nproduces optimized fully human antibodies and new classes of bispecific\nantibodies. We are shaping the next frontier of medicine with data-powered\ninsights from the Regeneron Genetics Center(®) and pioneering genetic\nmedicine platforms, enabling us to identify innovative targets and\ncomplementary approaches to potentially treat or cure diseases.\n\nFor more information, please visit www.Regeneron.com or follow Regeneron on\nLinkedIn\n(https://www.globenewswire.com/Tracker?data=QI7iwbOEP5Nt3eY6O9DJ5ORg7hPYBv8XQH8WVXm2FH7R0FOQNUZ66pb71BsXo8_FHaqYMI9tjZw0rAGgTkB-Rp_GRvSY89rMXPQMFGOXlLPMVPVjF2VTz3gPAhr7v7AdwxfuA9QZ79fJmn3YQJzbaaqDEBIQxCrbkgy-yZD8IWcRK6Rwukg6zTPiBcEiFLd6VTfCvymgUPxa-F53Jv4Wp2Cly_1-xXLjFwkFhuZ0HZGNG4cgK7Hhzry0kw_oLs0yD-1ECjfsu-L1BSvdn0Ei2_3s2U5V1MDAt_vg8QJD0jAy-HOOEa-eF1aNRzDebj9OQQgnQBLzITw88GZ9Ov-A9A==),\nInstagram\n(https://www.globenewswire.com/Tracker?data=0HwiC35dpfxAxfGQus9L6kf275LNg7SYJDQpOYiXGX55I9wqgpbGEqo_X1QUzr22-yKEHWXIU6OhgreeiL6fbxRe3x42cfi7sQQIOiLBNdLT1VBx2JT0TcZlIN8Hww8QunaRkjBx3g4TyweZQX1XQeucNoCeQAxeRpcL9mPKQmfbHnk3f-47dMyuPvTF72IusMVndXJsQAtWSzOXmFDr-_bcgKy7nSTyAow0Q98Y_X-suB5o7bA9jJEL2c4WvVxe-nU9HewV6Iqwv_pPZXEk4cLYLs9ieYqEIFXg5EJTfP1uobDlxvMIEVs3G4NO9X-EM1c00u8BwfXv8CbKopV3CtXE7ssBfTkZThFe5UOmAfOu2RrmfYGqNyESe04B3fGHvZSAfpS9_tVG364IR_3FFQ0Ytjf8nQTbPRQ5vqX9LSlYOc6rcLaFrecw98tRGVK7),\nFacebook\n(https://www.globenewswire.com/Tracker?data=NNq1XLk-3P43rDec3NkU2xCjEA79OoQ-FZm7pGqzmhLc33v88siQ-IaT9OM7EaU8nExLUiUDFHI2iaZMGjwdkfbv3XJhIdhal8nSLw26c9SgIpUI1QXm9CPCIHDgDjK1lC7YFtXxVT52v7Z1aJ_LlTpWIPc_1JT9mPa01aClNjggcHDj3q9ZDpwVQ04ARXaCKXrkbOmFyLqZqRS6MClhQpywYB8A71M3fFl_cjVPjFtn0CVErkHHvi24YYrzz8ucqtepYbsp7CEodr1hEci4TkDPHFQUgEi8bSSyQL5Dl0apJ1yzQrfP3G59LhF7n76DwLOKYgbVhLjVrJ-Kz-69531GilMbtnGdErqDnY6efC3-OR0V9UxJDNV4igGX0j4ek7lqO1t-k_0PzIYW09BljOZlXLBTlt1TsPTvQWB5s4N8lNpztFftHZZkqNpBP53l)\nor X\n(https://www.globenewswire.com/Tracker?data=EusBlYXJszXk_sYHsk1ykjAo9QbQuXcM6jJiLakUH4EVuUhH2UCvC72I5EtQPTyjXBYrg6g79_5EPdG4GV8grDbFu6CPfVtteQYgMmJpuoMC_0mGXKCePs2uoUk-eTBAHhhiatUk_nqBvCIwT4b686qK9_SV9TJj7I6YqfI6stwrGs3EPj9OQd1fSPP35rgXTMHlZ2aUODzd6tqAPfkPo-CtF0PnvKS-U1f_VA_nnKkWgPd9LzFs9ic0DvYclv0K6UuTR_-Arg7yGrwYgQI_XGyNHHnVXGClVOvuQLgE7b1FbnnbhChArGVeltb-9KxhKROhYlYvhTVr0iAyuLXC1ZtkwOM_wR-zDX689-blO-IXO0A7t2n_IiO0RX6asCv0YZhWTM57RLxI_rejR21AlQ==).\n\nForward-Looking Statements and Use of Digital Media\nThis press release includes forward-looking statements that involve risks and\nuncertainties relating to future events and the future performance of\nRegeneron Pharmaceuticals, Inc. (“Regeneron” or the “Company”), and\nactual events or results may differ materially from these forward-looking\nstatements. Words such as “anticipate,” “expect,” “intend,”\n“plan,” “believe,” “seek,” “estimate,” variations of such\nwords, and similar expressions are intended to identify such forward-looking\nstatements, although not all forward-looking statements contain these\nidentifying words. These statements concern, and these risks and uncertainties\ninclude, among others, the nature, timing, and possible success and\ntherapeutic applications of products marketed or otherwise commercialized by\nRegeneron and/or its collaborators or licensees (collectively,\n“Regeneron’s Products”) and product candidates being developed by\nRegeneron and/or its collaborators or licensees (collectively,\n“Regeneron’s Product Candidates”) and research and clinical programs now\nunderway or planned, including without limitation ubamatamab (MUC16xCD3\nbispecific antibody), Libtayo(®) (cemiplimab), and the other clinical\nprograms discussed or referenced in this press release; the likelihood,\ntiming, and scope of possible regulatory approval and commercial launch of\nRegeneron’s Product Candidates and new indications for Regeneron’s\nProducts, such as ubamatamab as a monotherapy or in combination with\nLibtayo(®) (cemiplimab) for the treatment of low-grade serous ovarian cancer;\nuncertainty of the utilization, market acceptance, and/or commercial success\nof Regeneron’s Products and Regeneron’s Product Candidates and the impact\nof studies (whether conducted by Regeneron or others and whether mandated or\nvoluntary), including the studies discussed or referenced in this press\nrelease, on any of the foregoing or any potential regulatory approval of\nRegeneron’s Products and Regeneron’s Product Candidates (such as\nubamatamab); the ability of Regeneron’s collaborators, licensees, suppliers,\nor other third parties (as applicable) to perform manufacturing, filling,\nfinishing, packaging, labeling, distribution, and other steps related to\nRegeneron’s Products and Regeneron’s Product Candidates; the ability of\nRegeneron to manage supply chains for multiple products and product candidates\nand risks associated with tariffs and other trade restrictions; safety issues\nresulting from the administration of Regeneron’s Products and Regeneron’s\nProduct Candidates (such as ubamatamab) in patients, including serious\ncomplications or side effects in connection with the use of Regeneron’s\nProducts and Regeneron’s Product Candidates in clinical trials;\ndeterminations by regulatory and administrative governmental authorities which\nmay delay or restrict Regeneron’s ability to continue to develop or\ncommercialize Regeneron’s Products and Regeneron’s Product Candidates;\nongoing regulatory obligations and oversight impacting Regeneron’s Products,\nresearch and clinical programs, and business, including those relating to\npatient privacy; the availability and extent of reimbursement or copay\nassistance for Regeneron’s Products from third-party payors and other third\nparties, including private payor healthcare and insurance programs, health\nmaintenance organizations, pharmacy benefit management companies, and\ngovernment programs such as Medicare and Medicaid; coverage and reimbursement\ndeterminations by such payors and other third parties and new policies and\nprocedures adopted by such payors and other third parties; changes to drug\npricing regulations and requirements and Regeneron’s pricing strategy,\nincluding in connection with Regeneron’s April 2026 agreements with the U.S.\ngovernment; other changes in laws, regulations, and policies affecting the\nhealthcare industry; competing products and product candidates (including\nbiosimilar products) that may be superior to, or more cost effective than,\nRegeneron’s Products and Regeneron’s Product Candidates; the extent to\nwhich the results from the research and development programs conducted by\nRegeneron and/or its collaborators or licensees may be replicated in other\nstudies and/or lead to advancement of product candidates to clinical trials,\ntherapeutic applications, or regulatory approval; unanticipated expenses; the\ncosts of developing, producing, and selling products; the ability of Regeneron\nto meet any of its financial projections or guidance and changes to the\nassumptions underlying those projections or guidance; the potential for any\nlicense, collaboration, or supply agreement, including Regeneron’s\nagreements with Sanofi and Bayer (or their respective affiliated companies, as\napplicable), to be cancelled or terminated; the impact of public health\noutbreaks, epidemics, or pandemics on Regeneron's business; and risks\nassociated with litigation and other proceedings and government investigations\nrelating to the Company and/or its operations (including the pending civil\nproceedings initiated or joined by the U.S. Department of Justice and the U.S.\nAttorney's Office for the District of Massachusetts), risks associated with\nintellectual property of other parties and pending or future litigation\nrelating thereto (including without limitation the patent litigation and other\nrelated proceedings relating to EYLEA(®) (aflibercept) Injection), the\nultimate outcome of any such proceedings and investigations, and the impact\nany of the foregoing may have on Regeneron’s business, prospects, operating\nresults, and financial condition. A more complete description of these and\nother material risks can be found in Regeneron’s filings with the U.S.\nSecurities and Exchange Commission, including its Form 10-K for the year ended\nDecember 31, 2025 and its Form 10-Q for the quarterly period ended June 30,\n2026. Any forward-looking statements are made based on management’s current\nbeliefs and judgment, and the reader is cautioned not to rely on any\nforward-looking statements made by Regeneron. Regeneron does not undertake any\nobligation to update (publicly or otherwise) any forward-looking statement,\nincluding without limitation any financial projection or guidance, whether as\na result of new information, future events, or otherwise.\n\nRegeneron uses its media and investor relations website and social media\noutlets to publish important information about the Company, including\ninformation that may be deemed material to investors. Financial and other\ninformation about Regeneron is routinely posted and is accessible on\nRegeneron's media and investor relations website\n(https://investor.regeneron.com) and its LinkedIn page\n(https://www.linkedin.com/company/regeneron-pharmaceuticals).\n\nContacts:\n\n Media Relations Taylor Ramsey Skott Tel: +1 914-409-2381 taylor.ramsey@regeneron.com  Investor Relations Mark Hudson Tel: +1 914-847-3482 mark.hudson@regeneron.com  \n\n(https://www.globenewswire.com/NewsRoom/AttachmentNg/add5ebc7-88c9-49dc-8834-abbb07c622d1)\n\n\n\nGlobeNewswire, Inc. 2026","article_body_html":"","raw_payload":{"data":{"id":"nGNX6dy7x7-20261001","title":"Ubamatamab (MUC16xCD3) Shows a High Rate of Durable Responses in Initial Study of Patients with Advanced Low-Grade Serous Ovarian Cancer (LGSOC)","author":"Globe Newswire","ticker":"REGN","created":"2026-10-01T15:35:00.144Z","tickers":["REGN"],"exchange":"NASDAQ","article_body":"LGSOC is a biologically distinct variant of ovarian cancer, with limited\ntreatment options, that is generally less responsive to conventional\nchemotherapy\n\nResults presented in a late-breaking plenary session at IGCS demonstrated a\n73% objective response rate and 11-month median progression-free survival in\n11 patients with recurrent and heavily pre-treated LGSOC treated with the\nhighest dose of ubamatamab in the trial  \n\nRegeneron has been enrolling a dedicated LGSOC cohort at this dose and will\nadvance ubamatamab into a confirmatory Phase 3 trial of this lethal cancer\nwith limited treatment options\n\nTARRYTOWN, N.Y., Oct. 01, 2026 (GLOBE NEWSWIRE) -- Regeneron Pharmaceuticals,\nInc. (NASDAQ: REGN) today announced the first results for the investigational\nubamatamab in patients with low-grade serous ovarian cancer (LGSOC). The data\nare from an ongoing Phase 1/2 trial in recurrent platinum-resistant high- or\nlow-grade serous ovarian cancer that were presented in a late-breaking plenary\noral session at the International Gynecologic Cancer Society (IGCS) 2026\nAnnual Global Meeting. Ubamatamab is a MUC16xCD3 bispecific antibody designed\nto bridge MUC16 on cancer cells with CD3-expressing T cells to facilitate\nlocal T-cell activation. Based on these preliminary trial results, Regeneron\nhas been enrolling a single-arm, potentially registrational LGSOC trial and\nwill be discussing the data with the U.S. Food and Drug Administration (FDA)\nin the coming months. Regeneron is also planning to initiate a confirmatory,\nrandomized, controlled Phase 3 trial to support the use of ubamatamab in\nLGSOC.\n\nLGSOC is a biologically distinct variant from the more common high-grade\nserous ovarian cancer (HGSOC), comprising up to 10% of serous ovarian cancer,\nwith typically uniformly high MUC16 expression and limited treatment options.\nThe disease often affects younger women and is characterized by slower-growing\ntumors than those seen in HGSOC, but frequently recurs and is less responsive\nto conventional chemotherapy with few treatment options. LGSOC has a median\noverall survival of approximately seven years from initial diagnosis, compared\nto approximately four years for HGSOC. In recurrent advanced LGSOC, historical\ntrial data have shown that objective response rates (ORRs) generally remain\nbelow 15% with chemotherapy and endocrine therapy, while the only approved\ntherapy has an ORR of 44% in biomarker-selected patient populations\n(representing about 30% of the overall LGSOC population).\n\n“The high rate of durable responses observed thus far with ubamatamab in\nlow-grade serous ovarian cancer, without requiring biomarker selection, are\nhighly encouraging and reinforce our excitement about MUC16 as a new\ntherapeutic target in this difficult-to-treat disease,” said Israel Lowy,\nM.D., Ph.D., Clinical Development Unit Head, Oncology, at Regeneron. “This\ninitial clinical evidence highlights the potential of our bispecific approach\nto bring a differentiated and first-in-class treatment option to patients in\nneed. We are pleased with the safety profile of the drug as well, and are\neager to build on these findings through our ongoing trial and planned\nconfirmatory Phase 3 trial.”\n\nData presented at IGCS focused on the LGSOC subset of 19 patients who had\nreceived a median of four prior lines of therapy and were dosed with\nintravenous ubamatamab ranging from 3 to 800 mg weekly or every three weeks.\nUbamatamab was given either as monotherapy or in combination with Libtayo(®\n)(cemiplimab).\n\nIncluded in the presentation were 11 patients treated with 800 mg of\nubamatamab monotherapy, eight treated weekly and three treated every three\nweeks. Results at the 800 mg doses showed a:\n* 73% ORR (95% Confidence Interval [CI]: 39.0 to 94.0), with all responses\nbeing partial responses\n* 9-month median duration of response (95% CI: 6.9 to not estimable [NE]), per\nKaplan-Meier estimate\n* 11-month median progression-free survival (95% CI: 3.0 to NE), per\nKaplan-Meier estimate\nSafety was assessed across all 19 patients in the LGSOC subset.\nTreatment-emergent adverse events (TEAEs) occurred in 100% of participants\n(n=19). Cytokine release syndrome occurred in 90% of participants (n=17), all\nof which were Grade 1 or 2. Serious TEAEs grade 3 or higher occurred in 21%\n(n=4) of participants and treatment-related adverse events (TRAEs) occurred in\n74% of participants (n=14). Grade 3 or higher TRAEs included neutropenia (21%;\nn=4), anemia (11%; n=2), increased alanine aminotransferase (11%; n=2),\nincreased aspartate aminotransferase (11%; n=2), abdominal pain (5%; n=1) and\nileus (5%; n=1). Most adverse events occurred during the step-up dosing\nperiod. One participant discontinued treatment due to a stroke considered\nunrelated to ubamatamab treatment; no TEAEs resulted in death.\n\nThe potential uses of ubamatamab described above are investigational, and its\nsafety and efficacy have not been evaluated by any regulatory authority.\n\nAbout the Trial\nThe ongoing, open-label, Phase 1/2 trial is evaluating ubamatamab alone and in\ncombination with Libtayo in adult patients with recurrent platinum-resistant\novarian cancer and other recurrent MUC16-expressing cancers.\n\nThe Phase 1 portion of the trial is primarily assessing safety, tolerability,\ndose-limiting toxicities and pharmacokinetics of ubamatamab, with efficacy\nevaluated as a secondary endpoint through measures such as ORR, duration of\nresponse and progression-free survival. The Phase 2 portion is evaluating the\nanti-tumor activity of ubamatamab, primarily through ORR, while continuing to\nassess safety and tolerability.\n\nA prospective, dedicated, potentially registrational cohort in the Phase 2\nportion of this trial is evaluating ubamatamab 800 mg monotherapy every three\nweeks in up to 100 patients with recurrent LGSOC and is currently enrolling.\nIf you are interested in learning more about this trial, please contact us\n(clinicaltrials@regeneron.com, +1 844 734 6643), or visit our clinical\ntrial website\n(https://www.globenewswire.com/Tracker?data=9edXPlzWP7w_G9B-WxsxzIuxzbmiwPDEJoVcFruPOSsR2iBBx0km3fz6kiCQd3jcVBzfFfd8lLjXeF6F93tIYy_6mEltUP4Nxt0_vxUSmqJzgdOkp1CfEr8lpCH-I6HsnFdQMjGHAAfek7SODM4bp85G42I67Hjrsn1uvBxzxhNhMViIXXU1q9k78a0Xbw0vo1ssqYzZZQJTFdUlraBHVg==).\n\nAbout Ovarian Cancer\nOvarian cancer is one of the most common gynecologic cancers and remains a\nleading cause of cancer-related mortality among women. It arises from the\nuncontrolled growth of abnormal cells in the ovary and is frequently diagnosed\nat an advanced stage, when disease has spread beyond the ovary. In 2026, an\nestimated 21,010 new cases of ovarian cancer were expected to be diagnosed in\nthe U.S., and approximately 12,450 women were expected to die from the\ndisease. Despite advances in treatment, ovarian cancer remains a significant\nunmet medical need, with many patients ultimately experiencing disease\nrecurrence and progression. \n\nLGSOC is a distinct form of ovarian cancer that occurs in younger women and\ncomprises up to 10% of new epithelial ovarian cancer cases. While LGSOC tumor\ncells tend to grow and divide more slowly than those seen in high-grade serous\novarian cancer, the disease frequently recurs and is less responsive to\nconventional chemotherapy. LGSOC has a median overall survival of\napproximately seven years from initial diagnosis, compared to approximately\nfour years for HGSOC. Although endocrine therapy and targeted therapies are\nused in selected patients, treatment options remain limited for many people\nwith recurrent disease.\n\nAbout Regeneron in Cancer\nWe aspire to turn revolutionary discoveries into medicines that can transform\nthe lives of those impacted by cancer. Our team around the world is driven to\nsolve the needs and challenges of those affected by one of the most serious\ndiseases of our time.\n\nBacked by our legacy of scientific innovation and a deep understanding of\nbiology, genetics and the immune system, we’re pursuing potential therapies\nacross more than 30 types of solid tumors and blood cancers. Our cancer\nstrategy is powered by cutting-edge technologies and therapies that can be\nflexibly combined to investigate potentially transformative treatments for\npatients. Oncology assets in clinical development comprise nearly half of\nRegeneron’s pipeline, and include checkpoint inhibitors, bispecific\nantibodies and costimulatory bispecific antibodies. Our approved PD-1\ninhibitor Libtayo serves as the backbone of many of our investigational\ncombinations. To complement our extensive in-house capabilities, we\ncollaborate with patients, healthcare providers, governments, biopharma\ncompanies and each other to further our shared goals. Together, we are united\nin the mission to serve as a beacon of transformation in cancer care.\n\nAbout Libtayo    \nLibtayo is a fully human monoclonal antibody targeting the immune checkpoint\nreceptor PD-1 on T cells and was invented using Regeneron's\nproprietary VelocImmune(®) technology. By binding to\nPD-1, Libtayo has been shown to block cancer cells from using the PD-1\npathway to suppress T-cell activation. Libtayo has been approved by\nregulatory authorities in more than 30 countries in one or more indications,\nincluding for certain adult patients with advanced basal cell carcinoma (BCC),\nadvanced cutaneous squamous cell carcinoma (CSCC), advanced NSCLC and\nadvanced cervical cancer.  \n\nIn the U.S., the generic name for Libtayo in its approved indications\nis cemiplimab-rwlc, with rwlc as the suffix designated in accordance\nwith Nonproprietary Naming of Biological Products Guidance for Industry\nissued by the U.S. FDA. Outside of the U.S., the generic name\nof Libtayo in its approved indications is cemiplimab.   \n\nThe extensive clinical program for Libtayo is focused on\ndifficult-to-treat cancers. Libtayo is currently being investigated in\ntrials as a monotherapy, as well as in combination with either conventional or\nnovel therapeutic approaches for other solid tumors. These potential uses\nare investigational, and their safety and efficacy have not been evaluated by\nany regulatory authority.     \n\nWhat is the most important information I should know about LIBTAYO?  \nLIBTAYO is a medicine that may treat certain cancers by working with your\nimmune system. LIBTAYO can cause your immune system to attack normal organs\nand tissues in any area of your body and can affect the way they work. These\nproblems can sometimes become severe or life-threatening and can lead to\ndeath. You can have more than one of these problems at the same time. These\nproblems may happen anytime during treatment or even after your treatment has\nended. \n\nCall or see your healthcare provider right away if you develop any new or\nworsening signs or symptoms, including:  \n* Lung problems: cough, shortness of breath, or chest pain  \n*\nIntestinal problems: diarrhea (loose stools) or more frequent bowel movements than\nusual, stools that are black, tarry, sticky or have blood or mucus, or severe\nstomach-area (abdomen) pain or tenderness  \n* Liver problems: yellowing of your skin or the whites of your\neyes,\nsevere nausea or vomiting, pain on the right side of your stomach-area\n(abdomen), dark urine (tea colored), or bleeding or bruising more easily than\nnormal  \n* Hormone gland problems: headache that will not go away or unusual\nheadaches, eye sensitivity to light, eye problems, rapid heartbeat, increased\nsweating, extreme tiredness, weight gain or weight loss, feeling more hungry\nor thirsty than usual, urinating more often than usual, hair loss, feeling\ncold, constipation, your voice gets deeper, dizziness or fainting, or changes\nin mood or behavior, such as decreased sex drive, irritability,\nor forgetfulness  \n* Kidney problems: decrease in your amount of urine, blood in your urine,\nswelling of your ankles, or loss of appetite  \n* Skin problems: rash, itching, skin blistering or peeling, painful sores or\nulcers in mouth or nose, throat, or genital area, fever or flu-like\nsymptoms, or swollen lymph nodes  \n* Problems can also happen in other organs and tissues. These are not all\nof the signs and symptoms of immune system problems that can happen with\nLIBTAYO. Call or see your healthcare provider right away for any new or\nworsening signs or symptoms, which may include: chest pain, irregular\nheartbeat, shortness of breath or swelling of ankles, confusion, sleepiness,\nmemory problems, changes in mood or behavior, stiff neck, balance problems,\ntingling or numbness of the arms or legs, double vision, blurry vision,\nsensitivity to light, eye pain, changes in eyesight, persistent or severe\nmuscle pain or weakness, muscle cramps, low red blood cells, or bruising  \n* Infusion reactions that can sometimes be severe or life-threatening. Signs\nand symptoms of infusion reactions may include: nausea, vomiting, chills\nor shaking, itching or rash, flushing, shortness of breath or wheezing,\ndizziness, feel like passing out, fever, back or neck pain,\nor facial swelling  \n* Rejection of a transplanted organ or tissue. Your healthcare provider\nshould tell you what signs and symptoms you should report and monitor you,\ndepending on the type of organ or tissue transplant that you have had  \n* Complications, including graft-versus-host disease (GVHD), in people who\nhave received a bone marrow (stem cell) transplant that uses donor stem cells\n(allogeneic). These complications can be serious and can lead to death.\nThese complications may happen if you underwent transplantation either before\nor after being treated with LIBTAYO. Your healthcare provider\nwill monitor you for these complications  \nGetting medical treatment right away may help keep these problems from\nbecoming more serious. Your healthcare provider will check you for these\nproblems during your treatment with LIBTAYO. Your healthcare provider may\ntreat you with corticosteroid or hormone replacement medicines. Your\nhealthcare provider may also need to delay or completely stop treatment with\nLIBTAYO if you have severe side effects.  \n  \nBefore you receive LIBTAYO, tell your healthcare provider about all your\nmedical conditions, including if you:  \n* have immune system problems such as Crohn’s disease, ulcerative colitis,\nor lupus  \n* have received an organ or tissue transplant, including corneal\ntransplant   \n* have received or plan to receive a stem cell transplant that uses donor stem\ncells (allogeneic)  \n* have received radiation treatment to your chest area  \n* have a condition that affects your nervous system, such as myasthenia gravis\nor Guillain-Barré syndrome  \n* are pregnant or plan to become pregnant. LIBTAYO can harm your\nunborn baby  \nFemales who are able to become pregnant:  \n* Your healthcare provider will give you a pregnancy test before you\nstart treatment  \n*\nYou should use an effective method of birth control during your treatment and for at least 4\nmonths after your last dose of LIBTAYO. Talk to your healthcare provider about\nbirth control methods that you can use during this time  \n* Tell your healthcare provider right away if you become pregnant or think\nyou may be pregnant during treatment with LIBTAYO  \n* are breastfeeding or plan to breastfeed. It is not known if LIBTAYO passes\ninto your breast milk.\nDo not breastfeed during treatment and for at\nleast 4 months after the last dose of LIBTAYO  \n Tell your healthcare provider about all the medicines you take, including\nprescription and over- the-counter medicines, vitamins, and herbal\nsupplements.  \n  \nThe most common side effects of LIBTAYO when used alone to treat CSCC that has\nspread or cannot be cured by surgery or radiation, BCC, or NSCLC include\ntiredness, muscle or bone pain, rash, diarrhea, and low levels of red blood\ncells (anemia). The most common side effects of LIBTAYO when used alone to\nhelp prevent CSCC from coming back include rash and itching. The most common\nside effects of LIBTAYO when used in combination with platinum-containing\nchemotherapy to treat NSCLC include hair loss, muscle or bone pain, nausea,\ntiredness, numbness, pain, tingling, or burning in your hands or feet, and\ndecreased appetite.  \n  \nThese are not all the possible side effects of LIBTAYO. Call your doctor for\nmedical advice about side effects. You may report side effects to FDA at\n1-800-FDA-1088. You may also report side effects to Regeneron\nPharmaceuticals at 1-877-542-8296.  \n  \nPlease see full Prescribing Information\n(https://www.globenewswire.com/Tracker?data=eDkQQma1HFJyvFGQMU3EYvBJA6XFp5BssWPVZpYdTqsZeFXVRTDDRQ3_4fhVXw8RtdBEv5rKYmDAEM6frhLnE06iiWhjLIrt-P2L5RFXQRT8ggSssvvpI9w1Dgjui3vbzmR9wAu9A01cQcuGOCweBQ==),\nincluding Medication Guide\n(https://www.globenewswire.com/Tracker?data=iYEPA0BNy5s793TutKKR83BoVkQiIC8ali-tWC-qp8Mxrwlq6hO1bT7LXi_6hDi-of-IUqRGpx5-tr31GXEdKkB4r4nuCugWxqlO5ccED-qaHJUd0JvWtNeKjtDo_wYUghPRUtlMsH17_Brrety4GA==).  \n\nAbout Regeneron's VelocImmune(®) Technology\nRegeneron's VelocImmune technology utilizes a proprietary genetically\nengineered mouse platform endowed with a genetically humanized immune system\nto produce optimized fully human antibodies. When Regeneron's co-Founder,\nPresident and Chief Scientific Officer George D. Yancopoulos was a graduate\nstudent with his mentor Frederick W. Alt in 1985, they were the first to\nenvision\n(https://www.globenewswire.com/Tracker?data=TT4yTOIA8lKzyANkEWYAxSwh1uu1HlYK6jZETn_v4Yab9cprlErKs-LW2rS1fXuRL2SHIQKzuHg6H3PKw8aSZUXGR7SS_y47_NduEJCXKZZoAO86Ysi4VDxqJHTu_WEvM5RId-Ml0h0VyfqQENHE-dm5mWAf6Q8CLBTErxiV-Vq8hSItgwwfQZAxmCvlc2Yo1euMRltPCe2j5CYAK4HHHvZGwP9JE5RBIzcSQfOEXRR750w6bEqYWLeS6NblEQy0I7z5H6DGX97CYTdIaqksOjIjjlKGARJPAx2ufIL-mFPLVKyXxZTPXK-GmWuUcM8fOjD_Js6CAU1M2Tgj70COzsb16c_OF1jHYeR6d_vUhAzvvUXe3OimN4AUmA7uSy_cZqU-LqlFQZnXXk7hj5hNEbLYqTS7fRbeLIWdkHKe0svLOoa4PE-09K0pJCr7xrsqPBXuSFmF6BUWNzNDKr57qhx9AZjtSHJerHKUqk8NxgVLMqtM2Gw1iAuvSr6qemUxhsxR8Iv--tnz6byLi-_r83dVrdkZXGp2EFEFbWWq6AuIJM3284OESA2sQuIMSYsa-csmHim0mSLGfvgt5voBnTYDcf7unSYXwOCTD_td4_PQJRnFUHLXqhmZsvSwYwR4SuU_d7b90YwxUBdwd3M2SzajRYJB7S6sesibDWx8-8-10pufXs0P6gmNmDfSrR8gOhTB9zJb_LNDMCaB3Au-BbzhIx7RYH4rKT98JJm8akMtbdgeho43uB7j67qH8YjeQn06nWwPSh0-KPTE18awEb8MNBQh6W7xo8vKvaQ34JiOrSuInBKlBweR-OziueYg_h3YEHxFUTGYMZ6Kx3_dy2eJkopu3MZnwP4hUnCaeFiPILHmnuJUZBax24CwakQK4L-lGmY-u6ewg-jn39hAAYmv5mXxyDW9Ch37i24ktzVMR6LKa3K1JYvl1ZIjnlOdl8YmHdP_jIHTwpfORI8t3dpaX0xJ_wDbVlB0MkzFBy5lTTJclvrkhok6c-NG1nMvo2G7vs2tELEnji3-Wuem5w==)\nmaking such a genetically humanized mouse, and Regeneron has spent decades\ninventing and developing VelocImmune and related VelociSuite(®) technologies.\nDr. Yancopoulos and his team have used VelocImmune technology to create a\nsubstantial proportion of all original, FDA-approved fully human monoclonal\nantibodies. This includes Dupixent(®) (dupilumab), Libtayo(®\n)(cemiplimab-rwlc), Praluent(®) (alirocumab), Kevzara(®), Evkeeza(®)\n(evinacumab-dgnb), Inmazeb(®) (atoltivimab, maftivimab and odesivimab-ebgn),\nVeopoz(®) (pozelimab-bbfg) and Pasatru™ (garetosmab-grts). In addition,\nREGEN-COV(®) (casirivimab and imdevimab) had been authorized by the FDA\nduring the COVID-19 pandemic until 2024. A total of 11 antibody and bispecific\nproducts have been approved or authorized worldwide that were invented or\nderived using VelocImmune technologies.\n\nAbout Regeneron \nRegeneron (NASDAQ: REGN) is a leading biotechnology company that invents,\ndevelops and commercializes life-transforming medicines for people with\nserious diseases. Founded and led by physician-scientists, our unique ability\nto repeatedly and consistently translate science into medicine has led to\nnumerous approved treatments and product candidates in development, most of\nwhich were homegrown in our laboratories. Our medicines and pipeline are\ndesigned to help patients with eye diseases, allergic and inflammatory\ndiseases, cancer, cardiovascular and metabolic diseases, neurological\ndiseases, hematologic conditions, infectious diseases, and rare diseases.\n\nRegeneron pushes the boundaries of scientific discovery and accelerates drug\ndevelopment using our proprietary technologies, such as VelociSuite(®), which\nproduces optimized fully human antibodies and new classes of bispecific\nantibodies. We are shaping the next frontier of medicine with data-powered\ninsights from the Regeneron Genetics Center(®) and pioneering genetic\nmedicine platforms, enabling us to identify innovative targets and\ncomplementary approaches to potentially treat or cure diseases.\n\nFor more information, please visit www.Regeneron.com or follow Regeneron on\nLinkedIn\n(https://www.globenewswire.com/Tracker?data=QI7iwbOEP5Nt3eY6O9DJ5ORg7hPYBv8XQH8WVXm2FH7R0FOQNUZ66pb71BsXo8_FHaqYMI9tjZw0rAGgTkB-Rp_GRvSY89rMXPQMFGOXlLPMVPVjF2VTz3gPAhr7v7AdwxfuA9QZ79fJmn3YQJzbaaqDEBIQxCrbkgy-yZD8IWcRK6Rwukg6zTPiBcEiFLd6VTfCvymgUPxa-F53Jv4Wp2Cly_1-xXLjFwkFhuZ0HZGNG4cgK7Hhzry0kw_oLs0yD-1ECjfsu-L1BSvdn0Ei2_3s2U5V1MDAt_vg8QJD0jAy-HOOEa-eF1aNRzDebj9OQQgnQBLzITw88GZ9Ov-A9A==),\nInstagram\n(https://www.globenewswire.com/Tracker?data=0HwiC35dpfxAxfGQus9L6kf275LNg7SYJDQpOYiXGX55I9wqgpbGEqo_X1QUzr22-yKEHWXIU6OhgreeiL6fbxRe3x42cfi7sQQIOiLBNdLT1VBx2JT0TcZlIN8Hww8QunaRkjBx3g4TyweZQX1XQeucNoCeQAxeRpcL9mPKQmfbHnk3f-47dMyuPvTF72IusMVndXJsQAtWSzOXmFDr-_bcgKy7nSTyAow0Q98Y_X-suB5o7bA9jJEL2c4WvVxe-nU9HewV6Iqwv_pPZXEk4cLYLs9ieYqEIFXg5EJTfP1uobDlxvMIEVs3G4NO9X-EM1c00u8BwfXv8CbKopV3CtXE7ssBfTkZThFe5UOmAfOu2RrmfYGqNyESe04B3fGHvZSAfpS9_tVG364IR_3FFQ0Ytjf8nQTbPRQ5vqX9LSlYOc6rcLaFrecw98tRGVK7),\nFacebook\n(https://www.globenewswire.com/Tracker?data=NNq1XLk-3P43rDec3NkU2xCjEA79OoQ-FZm7pGqzmhLc33v88siQ-IaT9OM7EaU8nExLUiUDFHI2iaZMGjwdkfbv3XJhIdhal8nSLw26c9SgIpUI1QXm9CPCIHDgDjK1lC7YFtXxVT52v7Z1aJ_LlTpWIPc_1JT9mPa01aClNjggcHDj3q9ZDpwVQ04ARXaCKXrkbOmFyLqZqRS6MClhQpywYB8A71M3fFl_cjVPjFtn0CVErkHHvi24YYrzz8ucqtepYbsp7CEodr1hEci4TkDPHFQUgEi8bSSyQL5Dl0apJ1yzQrfP3G59LhF7n76DwLOKYgbVhLjVrJ-Kz-69531GilMbtnGdErqDnY6efC3-OR0V9UxJDNV4igGX0j4ek7lqO1t-k_0PzIYW09BljOZlXLBTlt1TsPTvQWB5s4N8lNpztFftHZZkqNpBP53l)\nor X\n(https://www.globenewswire.com/Tracker?data=EusBlYXJszXk_sYHsk1ykjAo9QbQuXcM6jJiLakUH4EVuUhH2UCvC72I5EtQPTyjXBYrg6g79_5EPdG4GV8grDbFu6CPfVtteQYgMmJpuoMC_0mGXKCePs2uoUk-eTBAHhhiatUk_nqBvCIwT4b686qK9_SV9TJj7I6YqfI6stwrGs3EPj9OQd1fSPP35rgXTMHlZ2aUODzd6tqAPfkPo-CtF0PnvKS-U1f_VA_nnKkWgPd9LzFs9ic0DvYclv0K6UuTR_-Arg7yGrwYgQI_XGyNHHnVXGClVOvuQLgE7b1FbnnbhChArGVeltb-9KxhKROhYlYvhTVr0iAyuLXC1ZtkwOM_wR-zDX689-blO-IXO0A7t2n_IiO0RX6asCv0YZhWTM57RLxI_rejR21AlQ==).\n\nForward-Looking Statements and Use of Digital Media\nThis press release includes forward-looking statements that involve risks and\nuncertainties relating to future events and the future performance of\nRegeneron Pharmaceuticals, Inc. (“Regeneron” or the “Company”), and\nactual events or results may differ materially from these forward-looking\nstatements. Words such as “anticipate,” “expect,” “intend,”\n“plan,” “believe,” “seek,” “estimate,” variations of such\nwords, and similar expressions are intended to identify such forward-looking\nstatements, although not all forward-looking statements contain these\nidentifying words. These statements concern, and these risks and uncertainties\ninclude, among others, the nature, timing, and possible success and\ntherapeutic applications of products marketed or otherwise commercialized by\nRegeneron and/or its collaborators or licensees (collectively,\n“Regeneron’s Products”) and product candidates being developed by\nRegeneron and/or its collaborators or licensees (collectively,\n“Regeneron’s Product Candidates”) and research and clinical programs now\nunderway or planned, including without limitation ubamatamab (MUC16xCD3\nbispecific antibody), Libtayo(®) (cemiplimab), and the other clinical\nprograms discussed or referenced in this press release; the likelihood,\ntiming, and scope of possible regulatory approval and commercial launch of\nRegeneron’s Product Candidates and new indications for Regeneron’s\nProducts, such as ubamatamab as a monotherapy or in combination with\nLibtayo(®) (cemiplimab) for the treatment of low-grade serous ovarian cancer;\nuncertainty of the utilization, market acceptance, and/or commercial success\nof Regeneron’s Products and Regeneron’s Product Candidates and the impact\nof studies (whether conducted by Regeneron or others and whether mandated or\nvoluntary), including the studies discussed or referenced in this press\nrelease, on any of the foregoing or any potential regulatory approval of\nRegeneron’s Products and Regeneron’s Product Candidates (such as\nubamatamab); the ability of Regeneron’s collaborators, licensees, suppliers,\nor other third parties (as applicable) to perform manufacturing, filling,\nfinishing, packaging, labeling, distribution, and other steps related to\nRegeneron’s Products and Regeneron’s Product Candidates; the ability of\nRegeneron to manage supply chains for multiple products and product candidates\nand risks associated with tariffs and other trade restrictions; safety issues\nresulting from the administration of Regeneron’s Products and Regeneron’s\nProduct Candidates (such as ubamatamab) in patients, including serious\ncomplications or side effects in connection with the use of Regeneron’s\nProducts and Regeneron’s Product Candidates in clinical trials;\ndeterminations by regulatory and administrative governmental authorities which\nmay delay or restrict Regeneron’s ability to continue to develop or\ncommercialize Regeneron’s Products and Regeneron’s Product Candidates;\nongoing regulatory obligations and oversight impacting Regeneron’s Products,\nresearch and clinical programs, and business, including those relating to\npatient privacy; the availability and extent of reimbursement or copay\nassistance for Regeneron’s Products from third-party payors and other third\nparties, including private payor healthcare and insurance programs, health\nmaintenance organizations, pharmacy benefit management companies, and\ngovernment programs such as Medicare and Medicaid; coverage and reimbursement\ndeterminations by such payors and other third parties and new policies and\nprocedures adopted by such payors and other third parties; changes to drug\npricing regulations and requirements and Regeneron’s pricing strategy,\nincluding in connection with Regeneron’s April 2026 agreements with the U.S.\ngovernment; other changes in laws, regulations, and policies affecting the\nhealthcare industry; competing products and product candidates (including\nbiosimilar products) that may be superior to, or more cost effective than,\nRegeneron’s Products and Regeneron’s Product Candidates; the extent to\nwhich the results from the research and development programs conducted by\nRegeneron and/or its collaborators or licensees may be replicated in other\nstudies and/or lead to advancement of product candidates to clinical trials,\ntherapeutic applications, or regulatory approval; unanticipated expenses; the\ncosts of developing, producing, and selling products; the ability of Regeneron\nto meet any of its financial projections or guidance and changes to the\nassumptions underlying those projections or guidance; the potential for any\nlicense, collaboration, or supply agreement, including Regeneron’s\nagreements with Sanofi and Bayer (or their respective affiliated companies, as\napplicable), to be cancelled or terminated; the impact of public health\noutbreaks, epidemics, or pandemics on Regeneron's business; and risks\nassociated with litigation and other proceedings and government investigations\nrelating to the Company and/or its operations (including the pending civil\nproceedings initiated or joined by the U.S. Department of Justice and the U.S.\nAttorney's Office for the District of Massachusetts), risks associated with\nintellectual property of other parties and pending or future litigation\nrelating thereto (including without limitation the patent litigation and other\nrelated proceedings relating to EYLEA(®) (aflibercept) Injection), the\nultimate outcome of any such proceedings and investigations, and the impact\nany of the foregoing may have on Regeneron’s business, prospects, operating\nresults, and financial condition. A more complete description of these and\nother material risks can be found in Regeneron’s filings with the U.S.\nSecurities and Exchange Commission, including its Form 10-K for the year ended\nDecember 31, 2025 and its Form 10-Q for the quarterly period ended June 30,\n2026. Any forward-looking statements are made based on management’s current\nbeliefs and judgment, and the reader is cautioned not to rely on any\nforward-looking statements made by Regeneron. Regeneron does not undertake any\nobligation to update (publicly or otherwise) any forward-looking statement,\nincluding without limitation any financial projection or guidance, whether as\na result of new information, future events, or otherwise.\n\nRegeneron uses its media and investor relations website and social media\noutlets to publish important information about the Company, including\ninformation that may be deemed material to investors. Financial and other\ninformation about Regeneron is routinely posted and is accessible on\nRegeneron's media and investor relations website\n(https://investor.regeneron.com) and its LinkedIn page\n(https://www.linkedin.com/company/regeneron-pharmaceuticals).\n\nContacts:\n\n Media Relations Taylor Ramsey Skott Tel: +1 914-409-2381 taylor.ramsey@regeneron.com  Investor Relations Mark Hudson Tel: +1 914-847-3482 mark.hudson@regeneron.com  \n\n(https://www.globenewswire.com/NewsRoom/AttachmentNg/add5ebc7-88c9-49dc-8834-abbb07c622d1)\n\n\n\nGlobeNewswire, Inc. 2026"},"type":"article","timestamp":"2026-10-01T15:35:00.195652907Z","server_sent_at_ms":1790868900195},"received_at":"2026-10-01T15:35:00.351Z","source_url":null},"analysis":{"id":"147200","press_release_id":"158575","analysis_json":{"industry":{"label":"Biotechnology","sector":"Health Care"},"redFlags":["Very small efficacy dataset (11 patients at 800 mg; wide 95% CI of 39-94 on the 73% ORR)","All responses were partial responses; no complete responses reported","High CRS incidence (90%), though limited to Grade 1-2"],"eventType":"clinical_trial","narrative":"Regeneron reported first clinical results for ubamatamab, its MUC16xCD3 bispecific antibody, in recurrent low-grade serous ovarian cancer at the IGCS 2026 meeting.\n\nAmong 11 heavily pre-treated patients receiving 800 mg monotherapy, ubamatamab showed a 73% objective response rate and 11-month median progression-free survival — well above the sub-15% ORR typical of chemotherapy in this setting, and without biomarker selection.\n\nThe company is enrolling a dedicated, potentially registrational LGSOC cohort of up to 100 patients at the 800 mg dose, will discuss the data with the FDA in the coming months, and plans a confirmatory randomized Phase 3 trial.\n\nSafety showed cytokine release syndrome in 90% of the 19-patient LGSOC subset but all cases were Grade 1-2; no treatment-related deaths occurred.","sentiment":"bullish","agentHooks":{"shouldPost":true,"suggestedAngle":"Ubamatamab's 73% ORR without biomarker selection positions Regeneron for a first-in-class LGSOC launch, with FDA discussions ahead."},"keyFigures":{"drugName":"ubamatamab (MUC16xCD3 bispecific antibody)","phaseOfTrial":"Phase 1/2","customDimensions":{"orr":"73% at 800 mg dose (95% CI: 39.0-94.0)","median_pfs":"11 months","crs_incidence":"90%, all Grade 1 or 2","grade3plus_trae":"21%","patients_at_800mg":11,"lgsoc_subset_patients":19,"median_duration_of_response":"9 months"}},"quotedText":"The high rate of durable responses observed thus far with ubamatamab in low-grade serous ovarian cancer, without requiring biomarker selection, are highly encouraging and reinforce our excitement about MUC16 as a new therapeutic target in this difficult-to-treat disease","namedEntities":{"people":[{"name":"Israel Lowy, M.D., Ph.D.","role":"Clinical Development Unit Head, Oncology, Regeneron"},{"name":"George D. Yancopoulos","role":"Co-Founder, President and Chief Scientific Officer, Regeneron"}],"products":["ubamatamab","Libtayo (cemiplimab)","Dupixent","Praluent","Kevzara","Evkeeza","Inmazeb","Veopoz","Pasatru","REGEN-COV","EYLEA"],"companies":[{"name":"Regeneron Pharmaceuticals, Inc.","ticker":"REGN"},{"name":"U.S. Food and Drug Administration","relationship":"regulator"},{"name":"International Gynecologic Cancer Society (IGCS)","relationship":"conference/venue"},{"name":"Sanofi","relationship":"collaborator"},{"name":"Bayer","relationship":"collaborator"}],"dollarAmounts":[]},"materialImpact":{"score":3,"reasoning":"Positive Phase 1/2 data for ubamatamab in LGSOC with a 73% ORR at the 800 mg dose and plans for a potentially registrational cohort plus a confirmatory Phase 3. Promising pipeline news, but early-stage, small-n (11 patients), and not a binary regulatory event for a mega-cap like Regeneron."},"tickerRelevance":{"others":[],"primary":"REGN"},"globalImportance":45,"audienceRelevance":40,"eventTypeSecondary":[],"importanceComponents":{"tickerTier":"mega-cap biotech","eventGravity":"positive early-stage oncology data with registrational path","householdBrandBoost":true,"sampleSizeAdjustment":"small n of 11 limits confidence"}},"event_type":"clinical_trial","event_type_secondary":null,"sentiment":"bullish","material_impact_score":3,"narrative":"Regeneron reported first clinical results for ubamatamab, its MUC16xCD3 bispecific antibody, in recurrent low-grade serous ovarian cancer at the IGCS 2026 meeting.\n\nAmong 11 heavily pre-treated patients receiving 800 mg monotherapy, ubamatamab showed a 73% objective response rate and 11-month median progression-free survival — well above the sub-15% ORR typical of chemotherapy in this setting, and without biomarker selection.\n\nThe company is enrolling a dedicated, potentially registrational LGSOC cohort of up to 100 patients at the 800 mg dose, will discuss the data with the FDA in the coming months, and plans a confirmatory randomized Phase 3 trial.\n\nSafety showed cytokine release syndrome in 90% of the 19-patient LGSOC subset but all cases were Grade 1-2; no treatment-related deaths occurred.","key_figures":{"drugName":"ubamatamab (MUC16xCD3 bispecific antibody)","phaseOfTrial":"Phase 1/2","customDimensions":{"orr":"73% at 800 mg dose (95% CI: 39.0-94.0)","median_pfs":"11 months","crs_incidence":"90%, all Grade 1 or 2","grade3plus_trae":"21%","patients_at_800mg":11,"lgsoc_subset_patients":19,"median_duration_of_response":"9 months"}},"named_entities":{"people":[{"name":"Israel Lowy, M.D., Ph.D.","role":"Clinical Development Unit Head, Oncology, Regeneron"},{"name":"George D. Yancopoulos","role":"Co-Founder, President and Chief Scientific Officer, Regeneron"}],"products":["ubamatamab","Libtayo (cemiplimab)","Dupixent","Praluent","Kevzara","Evkeeza","Inmazeb","Veopoz","Pasatru","REGEN-COV","EYLEA"],"companies":[{"name":"Regeneron Pharmaceuticals, Inc.","ticker":"REGN"},{"name":"U.S. Food and Drug Administration","relationship":"regulator"},{"name":"International Gynecologic Cancer Society (IGCS)","relationship":"conference/venue"},{"name":"Sanofi","relationship":"collaborator"},{"name":"Bayer","relationship":"collaborator"}],"dollarAmounts":[]},"model_name":"glm-5.3-flashx","prompt_hash":"sha256:727b4b9429a443af","schema_hash":"sha256:05005c02d9cffac9","created_at":"2026-10-01T15:35:07.879Z","global_importance":45,"audience_relevance":40,"importance_components":{"tickerTier":"mega-cap biotech","eventGravity":"positive early-stage oncology data with registrational path","householdBrandBoost":true,"sampleSizeAdjustment":"small n of 11 limits confidence"}},"durationMs":7483,"modelName":"glm-5.3-flashx"}}