Page 1

Scholar Rock Scholar Rock Announces Positive 12 - Month Top - Line Results From the TOPAZ Phase 2 Clinical Trial Evaluating Apitegromab in Patients With Type 2 and Type 3 Spinal Muscular Atrophy ( SMA ) April 6 , 2021 - Data further demonstrate proof - of - concept for the therapeutic potential of apitegromab in patients with Type 2 and Type 3 SMA - Phase 3 registrational trial initiation expected by the end of 2021 - European Medicines Agency ( EMA ) granted Priority Medicines ( PRIME ) designation to apitegromab , recognizing unmet medical needs of patients with SMA - Scholar Rock to host webcast today at 8:00 am ET CAMBRIDGE , Mass .-- ( BUSINESS WIRE ) -- Apr . 6 , 2021-- Scholar Rock ( NASDAQ : SRRK ) , a clinical - stage biopharmaceutical company focused on the treatment of serious diseases in which protein growth factors play a fundamental role , today announced positive top - line data from the TOPAZ Phase 2 clinical trial evaluating apitegromab ( SRK - 015 ) in patients with Type 2 and Type 3 spinal muscular atrophy ( SMA ) . " These top - line 12 - month data provide further support towards establishing apitegromab as a potential first muscle - directed therapy for patients with SMA , " said Yung Chyung , M.D. , Chief Medical Officer of Scholar Rock . " The findings also offer important insights into myostatin biology and our scientific approach of targeting the latent forms of growth factors . We look forward to advancing the development and investigation of apitegromab as we plan to initiate a pivotal trial in SMA by the end of 2021 and explore its potential in additional disease areas . " Key findings from the 12 - month top - line analysis include : • Cohort 1 : 5-21 years of age , ambulatory Type 3 , 20 mg / kg dose monotherapy and in conjunction with nusinersen : • Observed a mean change from baseline in Revised Hammersmith Scale ( RHS ) of a 0.3 - point decline . • Majority of patients across the cohort ( 57 % , 13/23 of patients ) maintained or improved their motor function , as reflected by a > 0 - point change from baseline in RHS score , and 22 % of patients ( 5/23 ) attained a > 3 - point increase from baseline . o Results suggest potential clinical effect in certain patients in this population . • Cohort 2 : 5-21 years of age , Type 2 and non - ambulatory Type 3 who initiated nusinersen ≥5 years old , 20 mg / kg dose : • Observed a mean change from baseline in Hammersmith Functional Motor Scale Expanded ( HFMSE ) of a 0.6 - point improvement . • Majority of patients ( 64 % , 9/14 of patients ) attained a > 1 - point increase from baseline and 29 % of patients ( 4/14 ) attained a ≥3 - point increase from baseline . • Results support the potential durability of the improvements in motor function observed at the six - month interim analysis . • Cohort 3 : ≥2 years of age , Type 2 who initiated nusinersen < 5 years of age : o Observed a mean change from baseline in HFMSE of 7.1 - point and 5.3 - point improvements in the 20 mg / kg dose and the 2 mg / kg dose arms , respectively . • Across the full cohort , 59 % of patients ( 10/17 ) attained a > 5 - point increase and 35 % of patients ( 6/17 ) attained a > 10 - point increase from baseline . o Results demonstrate further improvements in motor function beyond what had been observed at the six - month interim analysis . • Dose response continued to be observed based upon clinical efficacy ( HFMSE improvements ) and pharmacodynamics ( target engagement ) . • No safety signals for apitegromab were identified as of the 12 - month top - line analysis . The five most frequently reported treatment - emergent adverse events ( TEAEs ) were headache , pyrexia , upper respiratory tract infection , cough , and nasopharyngitis . • All 57 patients who completed the 12 - month TOPAZ trial have opted into the extension period . " These 12 - month results from the Phase 2 apitegromab TOPAZ trial have built upon the previously announced exciting 6 - month interim results , " said Thomas Crawford , M.D. , Professor of Neurology at the Johns Hopkins School of Medicine and Lead Investigator of the TOPAZ trial . " There looks to be promising potential for a muscle - directed therapy that will complement the unmet need still evident , and likely emerging , in many individuals with SMA who receive SMN - enhancing therapies . Though much work remains to be done , I believe the results are wonderful news for the SMA community , and I am enthusiastic about the potential that apitegromab may offer for further meaningful functional improvements . " Detailed summary of the TOPAZ 12 - month top - line results by cohort Apitegromab is a selective inhibitor of the activation of latent myostatin . The TOPAZ Phase 2 proof - of - concept trial enrolled 58 patients with Type 2 and