{"success":true,"data":{"pressRelease":{"id":"141881","rtpr_id":"nBw7vC3W0a-20260911","ticker":"SRRK","exchange":"NASDAQ","all_tickers":["SRRK"],"title":"Scholar Rock Announces FDA Approval of ISEMBYLD™ (apitegromab-mstn), the First and Only Muscle-Targeted Treatment for Children and Adults with Spinal Muscular Atrophy (SMA)","author":"Business Wire","published_at":"2026-09-11T22:25:00.110Z","article_body":"Scholar Rock Announces FDA Approval of ISEMBYLD™ (apitegromab-mstn), the\nFirst and Only Muscle-Targeted Treatment for Children and Adults with Spinal\nMuscular Atrophy (SMA)\n\n\n * ISEMBYLD is approved for use in all adults and children ≥2 years of age with\nSMA who are currently receiving a survival motor neuron 2 (SMN2)-targeted\ntreatment\n\n\n * ISEMBYLD recommended dose of 10 mg/kg showed a robust, clinically meaningful\n2.2-point improvement in motor function as measured by the gold-standard\nHammersmith Functional Motor Scale-Expanded (HFMSE) compared to placebo, with\nall patients receiving SMN2-targeted background therapy (p = 0.0121*)\n\n\n * ISEMBYLD showed a ≥ 3-point increase in HFMSE in 34.2% of patients compared\nto 13.5% of patients on placebo (odds ratio 3.8; p = 0.0125*)\n\n\n * ISEMBYLD U.S. commercial launch underway with product available to ship in the\ncoming days; Scholar Rock Supports™ dedicated support team now available to\nassist patients and caregivers\n\n\n * Management to host investor call Monday, September 14, 2026, at 8:00 a.m. ET\n\n* nominal p-value\n\nScholar Rock (NASDAQ: SRRK), a global biopharmaceutical company dedicated to\nimproving the lives of patients with rare, severe, and debilitating\nneuromuscular diseases by applying its leading platform in myostatin biology,\ntoday announced that the FDA has approved ISEMBYLD (apitegromab-mstn) for the\ntreatment of spinal muscular atrophy (SMA) in adults and children two years of\nage and older who are currently receiving a survival motor neuron 2\n(SMN2)-targeted treatment.\n\nSMA is a rare, severe neuromuscular disease that results in irreversible loss\nof motor neurons and progressive muscle wasting, causing continuous motor\nfunction decline throughout life and diminishing the independence of both\nadults and children.\n\nISEMBYLD is the first and only muscle-targeted treatment to demonstrate motor\nfunction improvement in individuals with SMA currently receiving an\nSMN2-targeted treatment. In the Phase 3 randomized, placebo-controlled\nSAPPHIRE study, individuals receiving ISEMBYLD demonstrated a robust,\nclinically meaningful improvement in motor function after one year of\ntreatment while those on an SMN2-targeted treatment alone experienced a loss\nof motor function.\n\n“Today’s FDA approval of ISEMBYLD marks a defining moment for the SMA\ncommunity as we now launch the world’s first-ever muscle targeted treatment\nfor children and adults living with SMA in the U.S.,” said David L. Hallal,\nChairman and Chief Executive Officer of Scholar Rock. “After decades of\nfailed industry-wide efforts to unlock the potential of myostatin inhibition,\nScholar Rock has delivered a therapeutic breakthrough with ISEMBYLD. Our U.S.\ncommercial team is now engaging physicians, SMA care teams, and payers on\nbehalf of the SMA community and our Scholar Rock Supports™ team stands ready\nto provide dedicated, comprehensive assistance to patients and caregivers. I\nwould like to extend my deepest thanks to our clinical study investigators,\nCure SMA, and other patient advocacy groups for their dedication and support\non this journey. Above all, I want to express my heartfelt gratitude to the\npatients and families affected by SMA who participated in our clinical trials\nfor their trust in Scholar Rock and unwavering resilience every step of the\nway.”\n\n“The approval of ISEMBYLD as the first-ever treatment to directly target the\nmuscular component of SMA is a significant turning point for adults and\nchildren who have been waiting for innovative therapeutic options to improve\nmotor function,” said Kenneth Hobby, President of Cure SMA. “We appreciate\nthe FDA’s recognition, as reflected in this approval that supports access\nfor a broad population within the SMA community, that improving motor function\nis a significant unmet need that must be addressed with urgency. Such\nimprovements are fundamental to maintaining independence and to enabling\nparticipation in important activities of daily living from self-care to work\nand social interactions.”\n\nWith the approval of ISEMBYLD, Scholar Rock was awarded a Rare Pediatric\nDisease Priority Review Voucher, which may be used to obtain priority review\nfor a future marketing application.\n\nISEMBYLD Robust Clinical Efficacy and Safety Profile from Phase 3 SAPPHIRE\nStudy\n\nThe approval of ISEMBYLD was based on positive results from the Phase 3\npivotal, randomized, double-blind, placebo-controlled SAPPHIRE study. The\nSAPPHIRE study met its primary endpoint, and demonstrated a robust, clinically\nmeaningful 2.2-point improvement in the gold-standard Hammersmith Functional\nMotor Scale-Expanded (HFMSE) in patients receiving ISEMBYLD 10 mg/kg and an\nSMN2-targeted treatment compared to patients receiving an SMN2-targeted\ntreatment alone at one year (nominal p = 0.0121; main efficacy population 2 -\n12 years of age, n = 103). Additionally, 34.2% of ISEMBYLD-treated patients\nshowed a ≥ 3-point increase in HFMSE compared to 13.5% of placebo-treated\npatients (odds ratio of 3.8; nominal p = 0.0125).\n\nISEMBYLD has a well-characterized safety profile. The safety database includes\nmore than 500 individuals across all apitegromab clinical studies globally,\nsome of whom have been on treatment for more than 7 years. Ninety-eight\npercent of participants treated in SAPPHIRE elected to continue in the ONYX\nlong-term extension study. In the SAPPHIRE study, the most common adverse\nreactions were upper respiratory tract infections, vomiting, cough, other\nviral infections, headache, gastroenteritis, pharyngitis, and\nhypersensitivity. Fractures occurred in 9% of patients treated with ISEMBYLD\n10 mg/kg vs. 2% in placebo.\n\nFor further information, see Important Safety Information below.\n\n“Today’s approval of ISEMBYLD marks a new era for the treatment of SMA,”\nsaid Dr. Basil Darras, M.D., Associate Neurologist-in-Chief, Director of the\nNeuromuscular Center and Spinal Muscular Atrophy Program at Boston\nChildren’s Hospital, and a principal investigator in the SAPPHIRE study.\n“As neurologists, families consistently tell us that their top priority is\ngaining motor function, and we are now able to directly target the muscle, not\njust the motor neuron, for people living with SMA.”\n\nISEMBYLD Commercial Availability and Patient Access\n\nScholar Rock Supports is now available to assist patients who have been\nprescribed ISEMBYLD. This program is designed to provide personalized support\nfor patients and families, and includes help to understand insurance coverage,\nfinancial assistance programs for eligible patients, and disease and treatment\neducation. Scholar Rock Supports will also help patients and families navigate\ntheir site of care options, as well as ongoing infusion logistics. Based on\neligibility, infusions can be given at convenient locations including\nhospital, home, or infusion center. ISEMBYLD will be available to ship in the\ncoming days.\n\nScholar Rock is working closely with top commercial and government payers to\nestablish reliable, broad access to ISEMBYLD for appropriate patients.\n\nHealthcare providers and patients can learn more about Scholar Rock’s\npatient support services by visiting www.ScholarRockSupports.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fwww.ScholarRockSupports.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=www.ScholarRockSupports.com&index=1&md5=01e6a5a06a9c9f79d09c7bfa61e6f0ec)\nor calling 833-777-5444 (833-SRRK-444). For more information about ISEMBYLD\nand U.S. Prescribing Information, visit www.ISEMBYLD.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fwww.ISEMBYLD.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=www.ISEMBYLD.com&index=2&md5=b24ee876f01e75b074e4f1f6ead0aef5)\n.\n\nConference Call Information\n\nScholar Rock will host a conference call and webcast on Monday, September 14,\n2026, at 8:00 a.m. ET. To access the live audio webcast, please go to\n“Events and Presentations” in the Investors section of the Scholar Rock\nwebsite at https://investors.scholarrock.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Finvestors.scholarrock.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Finvestors.scholarrock.com&index=3&md5=2032a44e624eb9ac3ab75b7d15792c89)\n.\n\nTo participate via telephone, please register in advance here\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Furldefense.com%2Fv3%2F__https%3A%2Fregister-conf.media-server.com%2Fregister%2FBI610bc7a268a3492480018e14665d4836__%3B%21%21BIxG9zGngU4O%21hEyecV94dDeV7DFkSZKOGx8zXL1-w9weL63jEeZdMhNpI7hcRE8YxiinMppINsVnQE4FHCTNDhDUKciQhVk2fX_e8sk8zg%24&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=here&index=4&md5=3a1e1f97335c98a5960558142d99fbd1)\n. Upon registration, all telephone participants will receive a confirmation\nemail detailing how to join the conference call.\n\nA replay of the webcast will be available on the Company’s website for\napproximately 90 days.\n\nAbout ISEMBYLD\n\nISEMBYLD is a fully human monoclonal IgG4 antibody that binds to promyostatin\nand latent myostatin and inhibits the activation of myostatin, blocking\nmyostatin signaling. ISEMBYLD is approved in the United States for the\ntreatment of spinal muscular atrophy (SMA) in adults and pediatric patients 2\nyears of age and older who are currently receiving a survival motor neuron 2\n(SMN2)-targeted treatment.\n\nFor more information, visit www.ISEMBYLD.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fwww.ISEMBYLD.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=www.ISEMBYLD.com&index=5&md5=0a4f60a4f261b2d4a1a7b1bed028b736)\n.\n\nIndication and Important Safety Information\n\nWhat is ISEMBYLD (apitegromab-mstn)?\n\nISEMBYLD is a prescription medicine used to treat spinal muscular atrophy\n(SMA) in adults and children 2 years of age and older who are currently\nreceiving a survival motor neuron 2 (SMN2)-targeted treatment.\n\nIMPORTANT SAFETY INFORMATION\n\nBefore taking ISEMBYLD, tell your healthcare provider about all of your\nmedical conditions, including if you:\n\n\n * have a history of low bone density or bone fractures\n\n * are pregnant or plan to become pregnant. If you are pregnant or are planning\nto become pregnant, ask your healthcare provider for advice before taking this\nmedicine. It is not known if ISEMBYLD will harm your unborn baby. Tell your\nhealthcare provider right away if you become pregnant during treatment with\nISEMBYLD\n\n * are breastfeeding or plan to breastfeed. It is not known if ISEMBYLD passes\ninto breast milk. Talk to your healthcare provider about the best way to feed\nyour baby while on treatment with ISEMBYLD\n\nTell your healthcare provider about all the medicines you take, including\nprescription and over-the-counter medicines, vitamins, and herbal supplements.\nKeep a list of them to show your healthcare provider, including your\npharmacist, when you get a new medicine.\n\nWhat are the possible side effects of ISEMBYLD?\n\n\n * Fractures. Treatment with ISEMBYLD may increase the risk of bone fractures,\nincluding serious fractures. Bone fractures may happen with or without a fall\nor other injury. Your healthcare provider may consider stopping treatment with\nISEMBYLD if you experience a bone fracture during treatment.\n\nThe most common side effects of ISEMBYLD include:\n\n\n * upper respiratory tract infections\n\n * vomiting\n\n * cough\n\n * viral infections\n\n * headache\n\n * stomach flu (gastroenteritis)\n\n * sore throat (pharyngitis)\n\n * hypersensitivity\n\nThese are not all of the possible side effects of ISEMBYLD. Call your\nhealthcare provider for medical advice about side effects.\n\nYou are encouraged to report negative side effects of prescription drugs to\nthe FDA. Visit http://www.fda.gov/medwatch\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fwww.fda.gov%2Fmedwatch&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=http%3A%2F%2Fwww.fda.gov%2Fmedwatch&index=6&md5=5521d2b4c5a5d52392f0f35a6bcdbb29)\nor call 1-800-FDA-1088.\n\nPlease see full Prescribing Information\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fwww.scholarrock.com%2Fdocuments%2Flabel%2Fus%2FISEMBYLD_PI.pdf&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=Prescribing+Information&index=7&md5=9fd668a1517a72f11df27a8e3133bf93)\nand Patient Information\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fwww.scholarrock.com%2Fdocuments%2Flabel%2Fus%2FISEMBYLD_PatientInfo.pdf&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=Patient+Information&index=8&md5=4606b1cab5c75a34118fc1619a6cdc05)\n.\n\nAbout the SAPPHIRE Clinical Trial\n\nSAPPHIRE (NCT05156320\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fclinicaltrials.gov%2Fstudy%2FNCT05156320&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=NCT05156320&index=9&md5=9d5cecb85f5f767add89a12656eeeaae)\n) was a global, multi-national, randomized, double-blind, placebo-controlled\nPhase 3 clinical trial that evaluated the safety and efficacy of ISEMBYLD\n(apitegromab-mstn) in a total of 188 patients in 9 countries with a diagnosis\nof 5q SMA who were 2 to 21 years of age. Patients were randomized in a 1:1:1\nratio to receive ISEMBYLD 20 mg/kg (2 times the recommended dosage), ISEMBYLD\n10 mg/kg (the recommended dosage), or placebo, respectively, via intravenous\ninfusion once every 4 weeks for approximately 1 year. All patients enrolled in\nthis trial were receiving an approved SMN2-targeted treatment (either\nnusinersen or risdiplam).\n\nAbout SMA\n\nSpinal muscular atrophy (SMA) is a rare, severe, genetic neuromuscular\ndisease. The disease is characterized by the irreversible loss of motor\nneurons, atrophy of the voluntary muscles of the limbs and trunk, and\nprogressive muscle wasting that causes continuous motor function decline\nthroughout life and can diminish the independence of both children and adults.\nMotor function decline in SMA patients is affected by motor neuron health and\nmuscle responsiveness. SMN-targeted treatments are designed to prevent motor\nneuron loss but do not directly address muscle. It is estimated that\napproximately 35,000 SMA patients globally have been treated with an\nSMN-targeted treatment.\n\nAbout Scholar Rock\n\nScholar Rock is delivering muscle-targeted breakthroughs to transform the\ntreatment of spinal muscular atrophy (SMA) and other rare neuromuscular\ndiseases where muscle atrophy remains a critical unmet need. Scholar Rock\nintends to commercialize ISEMBYLD (apitegromab-mstn) globally, beginning in\nthe U.S. for individuals living with SMA who are 2 years of age and older and\ncurrently receiving a survival motor neuron 2 (SMN2)-targeted treatment.\n\nAs a global leader in myostatin biology, a field focused on proteins that\nregulate muscle mass, the biopharmaceutical company is named for the visual\nresemblance of a scholar rock to protein structures. Our commitment to unlock\nfundamentally different treatment approaches is powered by broad application\nof a proprietary platform, which has developed novel monoclonal antibodies to\nmodulate protein growth factors with extraordinary selectivity. Scholar Rock\nworks every day to create new possibilities for patients through its highly\ninnovative anti-myostatin program, including opportunities in additional rare\nneuromuscular diseases. Learn more about our neuromuscular franchise at\nScholarRock.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2F&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=ScholarRock.com&index=10&md5=af235377a7f0c8fbf451d85159f006ff)\nand follow @ScholarRock on X and on LinkedIn.\n\nScholar Rock(®) is a registered trademark and ISEMBYLD™ is a trademark of\nScholar Rock, Inc.\n\nAvailability of Other Information About Scholar Rock\n\nInvestors and others should note that we communicate with our investors and\nthe public using our company website www.scholarrock.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fwww.scholarrock.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=www.scholarrock.com&index=11&md5=b36729d8eb208dd218d08b0c647b6103)\n, including, but not limited to, company disclosures, investor presentations\nand FAQs, Securities and Exchange Commission filings, press releases, public\nconference call transcripts and webcast transcripts, as well as on X (formerly\nknown as Twitter) and LinkedIn. The information that we post on our website or\non X (formerly known as Twitter) or LinkedIn could be deemed to be material\ninformation. As a result, we encourage investors, the media and others\ninterested to review the information that we post there on a regular basis.\nThe contents of our website or social media shall not be deemed incorporated\nby reference in any filing under the Securities Act of 1933, as amended.\n\nForward-Looking Statements\n\nThis press release contains forward-looking statements within the meaning of\nthe Private Securities Litigation Reform Act of 1995, including, but not\nlimited to: Scholar Rock’s expectations regarding the U.S. commercial launch\nof ISEMBYLD, ISEMBYLD’s ability to support a broad patient population, the\npotential approval and launch of apitegromab in other geographies,\nISEMBYLD’s ability to change patient lives, the anticipated benefits of\nISEMBYLD for patients with SMA, and the Company’s business strategy, plans\nand prospects. The words “may,” “might,” “will,” “could,”\n“would,” “should,” “expect,” “anticipate,” “plan,”\n“believe,” “intend,” “estimate,” “potential,” “continue,”\n“target,” “goal,” and similar expressions are intended to identify\nforward-looking statements, although not all forward-looking statements\ncontain these identifying words. Any forward-looking statements in this press\nrelease are based on the Company’s current expectations, intentions, and\nbeliefs regarding future events, and are subject to risks and uncertainties\nthat could cause actual results to differ materially from those expressed or\nimplied by such statements. These risks and uncertainties include, without\nlimitation: the Company’s ability to successfully commercialize ISEMBYLD in\nthe U.S.; the Company’s ability to obtain and maintain regulatory approval\nof apitegromab in other jurisdictions; risks related to market acceptance,\ncompetition, pricing, reimbursement and access; manufacturing and supply chain\nrisks; Scholar Rock’s ability to obtain, maintain and protect its\nintellectual property; and Scholar Rock’s dependence on third parties for\ndevelopment and manufacture of ISEMBYLD, as well as those risks more fully\ndiscussed in the section entitled \"Risk Factors\" in Scholar Rock’s Quarterly\nReport on Form 10-Q for the quarter ended June 30, 2026, as well as\ndiscussions of potential risks, uncertainties, and other important factors in\nScholar Rock’s subsequent filings with the Securities and Exchange\nCommission. Any forward-looking statements represent Scholar Rock’s views\nonly as of today and should not be relied upon as representing its views as of\nany subsequent date. All information in this press release is as of the date\nof the release, and Scholar Rock undertakes no duty to update this information\nunless required by law.\n\nMultimedia Assets:\n\nhttps://scholarrock.com/media-kit/ISEMBYLD.jpg\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FISEMBYLD.jpg&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FISEMBYLD.jpg&index=12&md5=464986c853597fece2e5be8c2beaa92d)\n\nhttps://scholarrock.com/media-kit/ISEMBYLD_logo.jpg\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FISEMBYLD_logo.jpg&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FISEMBYLD_logo.jpg&index=13&md5=2abb97cd25af8e3c59e4f5100363fc7c)\n\nhttps://scholarrock.com/media-kit/Scholar_Rock_logo.png\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FScholar_Rock_logo.png&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FScholar_Rock_logo.png&index=14&md5=4de6ffb27a30a9365e971dfd9f340563)\n\nhttps://scholarrock.com/media-kit/Scholar_Rock_Supports.jpg\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FScholar_Rock_Supports.jpg&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FScholar_Rock_Supports.jpg&index=15&md5=e4784609685cfcdde4b2d097f54b6ad9)\n\n\n\nView source version on businesswire.com:\nhttps://www.businesswire.com/news/home/20260911564629/en/\n(https://www.businesswire.com/news/home/20260911564629/en/)\n\nScholar Rock: \n\nInvestors \n\nLaura Ekas, Ph.D.\n\nir@scholarrock.com \n(mailto:ir@scholarrock.com) \n917-439-0374\n\n\n\nMedia \n\nJeff Smith\n\n682-401-8428\n\nMolly MacLeod, Ph.D.\n\n802-579-5995\n\nmedia@scholarrock.com (mailto:media@scholarrock.com)\n\n\nCopyright Business Wire 2026","article_body_html":"","raw_payload":{"data":{"id":"nBw7vC3W0a-20260911","title":"Scholar Rock Announces FDA Approval of ISEMBYLD™ (apitegromab-mstn), the First and Only Muscle-Targeted Treatment for Children and Adults with Spinal Muscular Atrophy (SMA)","author":"Business Wire","ticker":"SRRK","created":"2026-09-11T22:25:00.110Z","tickers":["SRRK"],"exchange":"NASDAQ","article_body":"Scholar Rock Announces FDA Approval of ISEMBYLD™ (apitegromab-mstn), the\nFirst and Only Muscle-Targeted Treatment for Children and Adults with Spinal\nMuscular Atrophy (SMA)\n\n\n * ISEMBYLD is approved for use in all adults and children ≥2 years of age with\nSMA who are currently receiving a survival motor neuron 2 (SMN2)-targeted\ntreatment\n\n\n * ISEMBYLD recommended dose of 10 mg/kg showed a robust, clinically meaningful\n2.2-point improvement in motor function as measured by the gold-standard\nHammersmith Functional Motor Scale-Expanded (HFMSE) compared to placebo, with\nall patients receiving SMN2-targeted background therapy (p = 0.0121*)\n\n\n * ISEMBYLD showed a ≥ 3-point increase in HFMSE in 34.2% of patients compared\nto 13.5% of patients on placebo (odds ratio 3.8; p = 0.0125*)\n\n\n * ISEMBYLD U.S. commercial launch underway with product available to ship in the\ncoming days; Scholar Rock Supports™ dedicated support team now available to\nassist patients and caregivers\n\n\n * Management to host investor call Monday, September 14, 2026, at 8:00 a.m. ET\n\n* nominal p-value\n\nScholar Rock (NASDAQ: SRRK), a global biopharmaceutical company dedicated to\nimproving the lives of patients with rare, severe, and debilitating\nneuromuscular diseases by applying its leading platform in myostatin biology,\ntoday announced that the FDA has approved ISEMBYLD (apitegromab-mstn) for the\ntreatment of spinal muscular atrophy (SMA) in adults and children two years of\nage and older who are currently receiving a survival motor neuron 2\n(SMN2)-targeted treatment.\n\nSMA is a rare, severe neuromuscular disease that results in irreversible loss\nof motor neurons and progressive muscle wasting, causing continuous motor\nfunction decline throughout life and diminishing the independence of both\nadults and children.\n\nISEMBYLD is the first and only muscle-targeted treatment to demonstrate motor\nfunction improvement in individuals with SMA currently receiving an\nSMN2-targeted treatment. In the Phase 3 randomized, placebo-controlled\nSAPPHIRE study, individuals receiving ISEMBYLD demonstrated a robust,\nclinically meaningful improvement in motor function after one year of\ntreatment while those on an SMN2-targeted treatment alone experienced a loss\nof motor function.\n\n“Today’s FDA approval of ISEMBYLD marks a defining moment for the SMA\ncommunity as we now launch the world’s first-ever muscle targeted treatment\nfor children and adults living with SMA in the U.S.,” said David L. Hallal,\nChairman and Chief Executive Officer of Scholar Rock. “After decades of\nfailed industry-wide efforts to unlock the potential of myostatin inhibition,\nScholar Rock has delivered a therapeutic breakthrough with ISEMBYLD. Our U.S.\ncommercial team is now engaging physicians, SMA care teams, and payers on\nbehalf of the SMA community and our Scholar Rock Supports™ team stands ready\nto provide dedicated, comprehensive assistance to patients and caregivers. I\nwould like to extend my deepest thanks to our clinical study investigators,\nCure SMA, and other patient advocacy groups for their dedication and support\non this journey. Above all, I want to express my heartfelt gratitude to the\npatients and families affected by SMA who participated in our clinical trials\nfor their trust in Scholar Rock and unwavering resilience every step of the\nway.”\n\n“The approval of ISEMBYLD as the first-ever treatment to directly target the\nmuscular component of SMA is a significant turning point for adults and\nchildren who have been waiting for innovative therapeutic options to improve\nmotor function,” said Kenneth Hobby, President of Cure SMA. “We appreciate\nthe FDA’s recognition, as reflected in this approval that supports access\nfor a broad population within the SMA community, that improving motor function\nis a significant unmet need that must be addressed with urgency. Such\nimprovements are fundamental to maintaining independence and to enabling\nparticipation in important activities of daily living from self-care to work\nand social interactions.”\n\nWith the approval of ISEMBYLD, Scholar Rock was awarded a Rare Pediatric\nDisease Priority Review Voucher, which may be used to obtain priority review\nfor a future marketing application.\n\nISEMBYLD Robust Clinical Efficacy and Safety Profile from Phase 3 SAPPHIRE\nStudy\n\nThe approval of ISEMBYLD was based on positive results from the Phase 3\npivotal, randomized, double-blind, placebo-controlled SAPPHIRE study. The\nSAPPHIRE study met its primary endpoint, and demonstrated a robust, clinically\nmeaningful 2.2-point improvement in the gold-standard Hammersmith Functional\nMotor Scale-Expanded (HFMSE) in patients receiving ISEMBYLD 10 mg/kg and an\nSMN2-targeted treatment compared to patients receiving an SMN2-targeted\ntreatment alone at one year (nominal p = 0.0121; main efficacy population 2 -\n12 years of age, n = 103). Additionally, 34.2% of ISEMBYLD-treated patients\nshowed a ≥ 3-point increase in HFMSE compared to 13.5% of placebo-treated\npatients (odds ratio of 3.8; nominal p = 0.0125).\n\nISEMBYLD has a well-characterized safety profile. The safety database includes\nmore than 500 individuals across all apitegromab clinical studies globally,\nsome of whom have been on treatment for more than 7 years. Ninety-eight\npercent of participants treated in SAPPHIRE elected to continue in the ONYX\nlong-term extension study. In the SAPPHIRE study, the most common adverse\nreactions were upper respiratory tract infections, vomiting, cough, other\nviral infections, headache, gastroenteritis, pharyngitis, and\nhypersensitivity. Fractures occurred in 9% of patients treated with ISEMBYLD\n10 mg/kg vs. 2% in placebo.\n\nFor further information, see Important Safety Information below.\n\n“Today’s approval of ISEMBYLD marks a new era for the treatment of SMA,”\nsaid Dr. Basil Darras, M.D., Associate Neurologist-in-Chief, Director of the\nNeuromuscular Center and Spinal Muscular Atrophy Program at Boston\nChildren’s Hospital, and a principal investigator in the SAPPHIRE study.\n“As neurologists, families consistently tell us that their top priority is\ngaining motor function, and we are now able to directly target the muscle, not\njust the motor neuron, for people living with SMA.”\n\nISEMBYLD Commercial Availability and Patient Access\n\nScholar Rock Supports is now available to assist patients who have been\nprescribed ISEMBYLD. This program is designed to provide personalized support\nfor patients and families, and includes help to understand insurance coverage,\nfinancial assistance programs for eligible patients, and disease and treatment\neducation. Scholar Rock Supports will also help patients and families navigate\ntheir site of care options, as well as ongoing infusion logistics. Based on\neligibility, infusions can be given at convenient locations including\nhospital, home, or infusion center. ISEMBYLD will be available to ship in the\ncoming days.\n\nScholar Rock is working closely with top commercial and government payers to\nestablish reliable, broad access to ISEMBYLD for appropriate patients.\n\nHealthcare providers and patients can learn more about Scholar Rock’s\npatient support services by visiting www.ScholarRockSupports.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fwww.ScholarRockSupports.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=www.ScholarRockSupports.com&index=1&md5=01e6a5a06a9c9f79d09c7bfa61e6f0ec)\nor calling 833-777-5444 (833-SRRK-444). For more information about ISEMBYLD\nand U.S. Prescribing Information, visit www.ISEMBYLD.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fwww.ISEMBYLD.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=www.ISEMBYLD.com&index=2&md5=b24ee876f01e75b074e4f1f6ead0aef5)\n.\n\nConference Call Information\n\nScholar Rock will host a conference call and webcast on Monday, September 14,\n2026, at 8:00 a.m. ET. To access the live audio webcast, please go to\n“Events and Presentations” in the Investors section of the Scholar Rock\nwebsite at https://investors.scholarrock.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Finvestors.scholarrock.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Finvestors.scholarrock.com&index=3&md5=2032a44e624eb9ac3ab75b7d15792c89)\n.\n\nTo participate via telephone, please register in advance here\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Furldefense.com%2Fv3%2F__https%3A%2Fregister-conf.media-server.com%2Fregister%2FBI610bc7a268a3492480018e14665d4836__%3B%21%21BIxG9zGngU4O%21hEyecV94dDeV7DFkSZKOGx8zXL1-w9weL63jEeZdMhNpI7hcRE8YxiinMppINsVnQE4FHCTNDhDUKciQhVk2fX_e8sk8zg%24&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=here&index=4&md5=3a1e1f97335c98a5960558142d99fbd1)\n. Upon registration, all telephone participants will receive a confirmation\nemail detailing how to join the conference call.\n\nA replay of the webcast will be available on the Company’s website for\napproximately 90 days.\n\nAbout ISEMBYLD\n\nISEMBYLD is a fully human monoclonal IgG4 antibody that binds to promyostatin\nand latent myostatin and inhibits the activation of myostatin, blocking\nmyostatin signaling. ISEMBYLD is approved in the United States for the\ntreatment of spinal muscular atrophy (SMA) in adults and pediatric patients 2\nyears of age and older who are currently receiving a survival motor neuron 2\n(SMN2)-targeted treatment.\n\nFor more information, visit www.ISEMBYLD.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fwww.ISEMBYLD.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=www.ISEMBYLD.com&index=5&md5=0a4f60a4f261b2d4a1a7b1bed028b736)\n.\n\nIndication and Important Safety Information\n\nWhat is ISEMBYLD (apitegromab-mstn)?\n\nISEMBYLD is a prescription medicine used to treat spinal muscular atrophy\n(SMA) in adults and children 2 years of age and older who are currently\nreceiving a survival motor neuron 2 (SMN2)-targeted treatment.\n\nIMPORTANT SAFETY INFORMATION\n\nBefore taking ISEMBYLD, tell your healthcare provider about all of your\nmedical conditions, including if you:\n\n\n * have a history of low bone density or bone fractures\n\n * are pregnant or plan to become pregnant. If you are pregnant or are planning\nto become pregnant, ask your healthcare provider for advice before taking this\nmedicine. It is not known if ISEMBYLD will harm your unborn baby. Tell your\nhealthcare provider right away if you become pregnant during treatment with\nISEMBYLD\n\n * are breastfeeding or plan to breastfeed. It is not known if ISEMBYLD passes\ninto breast milk. Talk to your healthcare provider about the best way to feed\nyour baby while on treatment with ISEMBYLD\n\nTell your healthcare provider about all the medicines you take, including\nprescription and over-the-counter medicines, vitamins, and herbal supplements.\nKeep a list of them to show your healthcare provider, including your\npharmacist, when you get a new medicine.\n\nWhat are the possible side effects of ISEMBYLD?\n\n\n * Fractures. Treatment with ISEMBYLD may increase the risk of bone fractures,\nincluding serious fractures. Bone fractures may happen with or without a fall\nor other injury. Your healthcare provider may consider stopping treatment with\nISEMBYLD if you experience a bone fracture during treatment.\n\nThe most common side effects of ISEMBYLD include:\n\n\n * upper respiratory tract infections\n\n * vomiting\n\n * cough\n\n * viral infections\n\n * headache\n\n * stomach flu (gastroenteritis)\n\n * sore throat (pharyngitis)\n\n * hypersensitivity\n\nThese are not all of the possible side effects of ISEMBYLD. Call your\nhealthcare provider for medical advice about side effects.\n\nYou are encouraged to report negative side effects of prescription drugs to\nthe FDA. Visit http://www.fda.gov/medwatch\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fwww.fda.gov%2Fmedwatch&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=http%3A%2F%2Fwww.fda.gov%2Fmedwatch&index=6&md5=5521d2b4c5a5d52392f0f35a6bcdbb29)\nor call 1-800-FDA-1088.\n\nPlease see full Prescribing Information\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fwww.scholarrock.com%2Fdocuments%2Flabel%2Fus%2FISEMBYLD_PI.pdf&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=Prescribing+Information&index=7&md5=9fd668a1517a72f11df27a8e3133bf93)\nand Patient Information\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fwww.scholarrock.com%2Fdocuments%2Flabel%2Fus%2FISEMBYLD_PatientInfo.pdf&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=Patient+Information&index=8&md5=4606b1cab5c75a34118fc1619a6cdc05)\n.\n\nAbout the SAPPHIRE Clinical Trial\n\nSAPPHIRE (NCT05156320\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fclinicaltrials.gov%2Fstudy%2FNCT05156320&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=NCT05156320&index=9&md5=9d5cecb85f5f767add89a12656eeeaae)\n) was a global, multi-national, randomized, double-blind, placebo-controlled\nPhase 3 clinical trial that evaluated the safety and efficacy of ISEMBYLD\n(apitegromab-mstn) in a total of 188 patients in 9 countries with a diagnosis\nof 5q SMA who were 2 to 21 years of age. Patients were randomized in a 1:1:1\nratio to receive ISEMBYLD 20 mg/kg (2 times the recommended dosage), ISEMBYLD\n10 mg/kg (the recommended dosage), or placebo, respectively, via intravenous\ninfusion once every 4 weeks for approximately 1 year. All patients enrolled in\nthis trial were receiving an approved SMN2-targeted treatment (either\nnusinersen or risdiplam).\n\nAbout SMA\n\nSpinal muscular atrophy (SMA) is a rare, severe, genetic neuromuscular\ndisease. The disease is characterized by the irreversible loss of motor\nneurons, atrophy of the voluntary muscles of the limbs and trunk, and\nprogressive muscle wasting that causes continuous motor function decline\nthroughout life and can diminish the independence of both children and adults.\nMotor function decline in SMA patients is affected by motor neuron health and\nmuscle responsiveness. SMN-targeted treatments are designed to prevent motor\nneuron loss but do not directly address muscle. It is estimated that\napproximately 35,000 SMA patients globally have been treated with an\nSMN-targeted treatment.\n\nAbout Scholar Rock\n\nScholar Rock is delivering muscle-targeted breakthroughs to transform the\ntreatment of spinal muscular atrophy (SMA) and other rare neuromuscular\ndiseases where muscle atrophy remains a critical unmet need. Scholar Rock\nintends to commercialize ISEMBYLD (apitegromab-mstn) globally, beginning in\nthe U.S. for individuals living with SMA who are 2 years of age and older and\ncurrently receiving a survival motor neuron 2 (SMN2)-targeted treatment.\n\nAs a global leader in myostatin biology, a field focused on proteins that\nregulate muscle mass, the biopharmaceutical company is named for the visual\nresemblance of a scholar rock to protein structures. Our commitment to unlock\nfundamentally different treatment approaches is powered by broad application\nof a proprietary platform, which has developed novel monoclonal antibodies to\nmodulate protein growth factors with extraordinary selectivity. Scholar Rock\nworks every day to create new possibilities for patients through its highly\ninnovative anti-myostatin program, including opportunities in additional rare\nneuromuscular diseases. Learn more about our neuromuscular franchise at\nScholarRock.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2F&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=ScholarRock.com&index=10&md5=af235377a7f0c8fbf451d85159f006ff)\nand follow @ScholarRock on X and on LinkedIn.\n\nScholar Rock(®) is a registered trademark and ISEMBYLD™ is a trademark of\nScholar Rock, Inc.\n\nAvailability of Other Information About Scholar Rock\n\nInvestors and others should note that we communicate with our investors and\nthe public using our company website www.scholarrock.com\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fwww.scholarrock.com&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=www.scholarrock.com&index=11&md5=b36729d8eb208dd218d08b0c647b6103)\n, including, but not limited to, company disclosures, investor presentations\nand FAQs, Securities and Exchange Commission filings, press releases, public\nconference call transcripts and webcast transcripts, as well as on X (formerly\nknown as Twitter) and LinkedIn. The information that we post on our website or\non X (formerly known as Twitter) or LinkedIn could be deemed to be material\ninformation. As a result, we encourage investors, the media and others\ninterested to review the information that we post there on a regular basis.\nThe contents of our website or social media shall not be deemed incorporated\nby reference in any filing under the Securities Act of 1933, as amended.\n\nForward-Looking Statements\n\nThis press release contains forward-looking statements within the meaning of\nthe Private Securities Litigation Reform Act of 1995, including, but not\nlimited to: Scholar Rock’s expectations regarding the U.S. commercial launch\nof ISEMBYLD, ISEMBYLD’s ability to support a broad patient population, the\npotential approval and launch of apitegromab in other geographies,\nISEMBYLD’s ability to change patient lives, the anticipated benefits of\nISEMBYLD for patients with SMA, and the Company’s business strategy, plans\nand prospects. The words “may,” “might,” “will,” “could,”\n“would,” “should,” “expect,” “anticipate,” “plan,”\n“believe,” “intend,” “estimate,” “potential,” “continue,”\n“target,” “goal,” and similar expressions are intended to identify\nforward-looking statements, although not all forward-looking statements\ncontain these identifying words. Any forward-looking statements in this press\nrelease are based on the Company’s current expectations, intentions, and\nbeliefs regarding future events, and are subject to risks and uncertainties\nthat could cause actual results to differ materially from those expressed or\nimplied by such statements. These risks and uncertainties include, without\nlimitation: the Company’s ability to successfully commercialize ISEMBYLD in\nthe U.S.; the Company’s ability to obtain and maintain regulatory approval\nof apitegromab in other jurisdictions; risks related to market acceptance,\ncompetition, pricing, reimbursement and access; manufacturing and supply chain\nrisks; Scholar Rock’s ability to obtain, maintain and protect its\nintellectual property; and Scholar Rock’s dependence on third parties for\ndevelopment and manufacture of ISEMBYLD, as well as those risks more fully\ndiscussed in the section entitled \"Risk Factors\" in Scholar Rock’s Quarterly\nReport on Form 10-Q for the quarter ended June 30, 2026, as well as\ndiscussions of potential risks, uncertainties, and other important factors in\nScholar Rock’s subsequent filings with the Securities and Exchange\nCommission. Any forward-looking statements represent Scholar Rock’s views\nonly as of today and should not be relied upon as representing its views as of\nany subsequent date. All information in this press release is as of the date\nof the release, and Scholar Rock undertakes no duty to update this information\nunless required by law.\n\nMultimedia Assets:\n\nhttps://scholarrock.com/media-kit/ISEMBYLD.jpg\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FISEMBYLD.jpg&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FISEMBYLD.jpg&index=12&md5=464986c853597fece2e5be8c2beaa92d)\n\nhttps://scholarrock.com/media-kit/ISEMBYLD_logo.jpg\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FISEMBYLD_logo.jpg&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FISEMBYLD_logo.jpg&index=13&md5=2abb97cd25af8e3c59e4f5100363fc7c)\n\nhttps://scholarrock.com/media-kit/Scholar_Rock_logo.png\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FScholar_Rock_logo.png&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FScholar_Rock_logo.png&index=14&md5=4de6ffb27a30a9365e971dfd9f340563)\n\nhttps://scholarrock.com/media-kit/Scholar_Rock_Supports.jpg\n(https://cts.businesswire.com/ct/CT?id=smartlink&url=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FScholar_Rock_Supports.jpg&esheet=54602249&newsitemid=20260911564629&lan=en-US&anchor=https%3A%2F%2Fscholarrock.com%2Fmedia-kit%2FScholar_Rock_Supports.jpg&index=15&md5=e4784609685cfcdde4b2d097f54b6ad9)\n\n\n\nView source version on businesswire.com:\nhttps://www.businesswire.com/news/home/20260911564629/en/\n(https://www.businesswire.com/news/home/20260911564629/en/)\n\nScholar Rock: \n\nInvestors \n\nLaura Ekas, Ph.D.\n\nir@scholarrock.com \n(mailto:ir@scholarrock.com) \n917-439-0374\n\n\n\nMedia \n\nJeff Smith\n\n682-401-8428\n\nMolly MacLeod, Ph.D.\n\n802-579-5995\n\nmedia@scholarrock.com (mailto:media@scholarrock.com)\n\n\nCopyright Business Wire 2026"},"type":"article","timestamp":"2026-09-11T22:25:00.170171936Z","server_sent_at_ms":1789165500170},"received_at":"2026-09-11T22:25:00.334Z","source_url":"https://www.businesswire.com/news/home/20260911564629/en/"},"analysis":{"id":"130717","press_release_id":"141881","analysis_json":{"industry":{"label":"Biotechnology","sector":"Health Care"},"redFlags":["Label includes fracture risk: 9% of patients on 10 mg/kg dose vs 2% on placebo","Primary endpoint p-values are nominal, not multiplicity-adjusted","Launch pricing and reimbursement terms not disclosed in the release"],"eventType":"fda_approval","narrative":"Scholar Rock won FDA approval for ISEMBYLD (apitegromab-mstn), the first and only muscle-targeted treatment for spinal muscular atrophy, covering adults and children 2 years and older already receiving an SMN2-targeted therapy.\n\nApproval was based on the Phase 3 SAPPHIRE study, which showed a 2.2-point HFMSE improvement versus placebo at one year (nominal p=0.0121), with 34.2% of treated patients gaining 3 or more points versus 13.5% on placebo (odds ratio 3.8).\n\nThe U.S. commercial launch is already underway with product shipping in the coming days, and the company was awarded a Rare Pediatric Disease Priority Review Voucher alongside the approval.\n\nThe label carries a fracture risk -- 9% of patients on the recommended 10 mg/kg dose versus 2% on placebo -- and management hosts an investor call on Monday, September 14, 2026 at 8:00 a.m. ET.","sentiment":"bullish","agentHooks":{"shouldPost":true,"suggestedAngle":"First-ever muscle-targeted SMA approval transitions SRRK to commercial-stage with a PRV in hand -- launch uptake and pricing color due on the Sept 14 investor call."},"keyFigures":{"drugName":"ISEMBYLD (apitegromab-mstn)","phaseOfTrial":"Phase 3","customDimensions":{"hfmse_p_value":"nominal p = 0.0121","safety_database":"more than 500 individuals across apitegromab studies","recommended_dose":"10 mg/kg IV infusion once every 4 weeks","hfmse_improvement":"2.2-point improvement vs placebo at one year","responder_p_value":"nominal p = 0.0125","sapphire_countries":9,"sapphire_enrollment":188,"hfmse_responder_rate":"34.2%","responder_odds_ratio":3.8,"fracture_rate_placebo":"2%","fracture_rate_treated":"9%","placebo_responder_rate":"13.5%","priority_review_voucher":"Rare Pediatric Disease Priority Review Voucher awarded","onyx_extension_continuation":"98%","smn2_treated_sma_patients_global":35000}},"quotedText":"Today’s FDA approval of ISEMBYLD marks a defining moment for the SMA community as we now launch the world’s first-ever muscle targeted treatment for children and adults living with SMA in the U.S.","namedEntities":{"people":[{"name":"David L. Hallal","role":"Chairman and CEO of Scholar Rock"},{"name":"Kenneth Hobby","role":"President of Cure SMA"},{"name":"Dr. Basil Darras","role":"Associate Neurologist-in-Chief, Boston Children's Hospital; SAPPHIRE principal investigator"}],"products":["ISEMBYLD (apitegromab-mstn)","apitegromab","Scholar Rock Supports","nusinersen","risdiplam"],"companies":[{"name":"Scholar Rock","ticker":"SRRK","relationship":"filer"},{"name":"Cure SMA","relationship":"patient advocacy group"},{"name":"Boston Children's Hospital","relationship":"clinical study site"}],"dollarAmounts":[]},"materialImpact":{"score":5,"reasoning":"FDA approval of Scholar Rock's lead and first-ever commercial product -- a binary regulatory event that converts the company to commercial-stage, with U.S. launch and shipping beginning within days and a Priority Review Voucher awarded."},"tickerRelevance":{"others":[],"primary":"SRRK"},"globalImportance":52,"audienceRelevance":45,"eventTypeSecondary":["product_launch"],"importanceComponents":{"prvAwarded":true,"tickerTier":"mid-cap biotech","eventGravity":"first-ever product approval and commercial-stage transition; first-in-class muscle-targeted SMA therapy","sectorWeight":"biotech FDA binary events carry outsized stock sensitivity","householdBrandBoost":null,"retailFavoriteBoost":"SRRK is a widely followed catalyst-driven biotech name"}},"event_type":"fda_approval","event_type_secondary":["product_launch"],"sentiment":"bullish","material_impact_score":5,"narrative":"Scholar Rock won FDA approval for ISEMBYLD (apitegromab-mstn), the first and only muscle-targeted treatment for spinal muscular atrophy, covering adults and children 2 years and older already receiving an SMN2-targeted therapy.\n\nApproval was based on the Phase 3 SAPPHIRE study, which showed a 2.2-point HFMSE improvement versus placebo at one year (nominal p=0.0121), with 34.2% of treated patients gaining 3 or more points versus 13.5% on placebo (odds ratio 3.8).\n\nThe U.S. commercial launch is already underway with product shipping in the coming days, and the company was awarded a Rare Pediatric Disease Priority Review Voucher alongside the approval.\n\nThe label carries a fracture risk -- 9% of patients on the recommended 10 mg/kg dose versus 2% on placebo -- and management hosts an investor call on Monday, September 14, 2026 at 8:00 a.m. ET.","key_figures":{"drugName":"ISEMBYLD (apitegromab-mstn)","phaseOfTrial":"Phase 3","customDimensions":{"hfmse_p_value":"nominal p = 0.0121","safety_database":"more than 500 individuals across apitegromab studies","recommended_dose":"10 mg/kg IV infusion once every 4 weeks","hfmse_improvement":"2.2-point improvement vs placebo at one year","responder_p_value":"nominal p = 0.0125","sapphire_countries":9,"sapphire_enrollment":188,"hfmse_responder_rate":"34.2%","responder_odds_ratio":3.8,"fracture_rate_placebo":"2%","fracture_rate_treated":"9%","placebo_responder_rate":"13.5%","priority_review_voucher":"Rare Pediatric Disease Priority Review Voucher awarded","onyx_extension_continuation":"98%","smn2_treated_sma_patients_global":35000}},"named_entities":{"people":[{"name":"David L. Hallal","role":"Chairman and CEO of Scholar Rock"},{"name":"Kenneth Hobby","role":"President of Cure SMA"},{"name":"Dr. Basil Darras","role":"Associate Neurologist-in-Chief, Boston Children's Hospital; SAPPHIRE principal investigator"}],"products":["ISEMBYLD (apitegromab-mstn)","apitegromab","Scholar Rock Supports","nusinersen","risdiplam"],"companies":[{"name":"Scholar Rock","ticker":"SRRK","relationship":"filer"},{"name":"Cure SMA","relationship":"patient advocacy group"},{"name":"Boston Children's Hospital","relationship":"clinical study site"}],"dollarAmounts":[]},"model_name":"glm-5.3-flash","prompt_hash":"sha256:727b4b9429a443af","schema_hash":"sha256:05005c02d9cffac9","created_at":"2026-09-11T22:25:27.375Z","global_importance":52,"audience_relevance":45,"importance_components":{"prvAwarded":true,"tickerTier":"mid-cap biotech","eventGravity":"first-ever product approval and commercial-stage transition; first-in-class muscle-targeted SMA therapy","sectorWeight":"biotech FDA binary events carry outsized stock sensitivity","householdBrandBoost":null,"retailFavoriteBoost":"SRRK is a widely followed catalyst-driven biotech name"}},"durationMs":27026,"modelName":"glm-5.3-flash"}}