Page 1

Scholar Rock Scholar Rock Presents TOPAZ Phase 2 Data Showing the Transformative Potential of Apitegromab in Patients with Type 2 and 3 Spinal Muscular Atrophy ( SMA ) at the 2021 Virtual SMA Research & Clinical Care Meeting June 11 , 2021 - Majority ( 74 % ) of patients with non - ambulatory Type 2 and Type 3 SMA achieved a clinical improvement in Hammersmith Functional Motor Scale Expanded ( HFMSE ) after 12 months - New exploratory analysis of TOPAZ data found no correlation between duration of prior nusinersen treatment and increases in HFMSE , adding support that observed motor function improvements may be attributable to apitegromab - Company to host KOL event and panel discussion on apitegromab's therapeutic potential in patients with SMA on June 15 , 2021 at 10:00 am ET CAMBRIDGE , Mass .-- ( BUSINESS WIRE ) -- Jun . 11 , 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 an oral presentation of TOPAZ Phase 2 trial results by the lead principal investigator , Thomas Crawford , M.D. of Johns Hopkins Medicine , at the Cure SMA Annual SMA Conference . In the TOPAZ trial , treatment with apitegromab in conjunction with nusinersen in patients with Type 2 and 3 SMA led to meaningful motor function improvements of up to 20 points as measured by HFMSE . New exploratory analyses being presented further support apitegromab's potential to improve motor function in patients with SMA . " The TOPAZ results show that apitegromab has promising potential to benefit the large portion of individuals with SMA who still manifest muscle weakness , " said Thomas Crawford , M.D. , Professor of Neurology at the Johns Hopkins School of Medicine and Lead Investigator of the TOPAZ trial . " In recent years , there have been some really remarkable advances in therapy for SMA that increase the low levels of SMN protein in motor neurons . But these findings suggest the fortunate streak for SMA therapeutics can potentially continue , this time targeting the persistent weakness in a complementary fashion at the level of muscle . " SMA remains a devastating and debilitating disease despite the utilization of SMN upregulators that prevent further motor neuron deterioration . A muscle - directed approach such as apitegromab , a selective inhibitor of myostatin activation , has the potential to complement SMN upregulators and address motor function impairments in patients with SMA . Scholar Rock's TOPAZ Phase 2 trial ( NCT03921528 ) evaluated apitegromab across a broad age range ( 2-21 years ) of patients with Type 2 and 3 SMA . With the exception of some ambulatory patients who received apitegromab as a monotherapy , patients enrolled in TOPAZ were receiving chronic maintenance doses of nusinersen . Both non - ambulatory cohorts had received more than 5.0 mean maintenance doses or approximately 2 years of treatment at baseline . Clinical data from the CHERISH and SHINE studies of nusinersen offer background insights into this patient population . 1 These studies observed that nusinersen - treated patients primarily experienced stabilization or only slight increases in HFMSE scores beyond the initial 15 - month treatment period . 2 In addition , even in the initial 15 - month treatment period , patients who initiated nusinersen treatment age ≥5 on average experienced declines in HFMSE and rarely attained a ≥3 - point increase in HFMSE in a 12 - month timeframe.3 Results following 12 - months of treatment with apitegromab added to background nusinersen therapy , in the TOPAZ trial , included : • Majority ( 74 % , 23/31 ) of non - ambulatory patients showed a clinical improvement ( ≥1 - point increase ) in Hammersmith Functional Motor Scale Expanded ( HFMSE ) . • In the non - ambulatory cohort of patients ( mean age 3.8 ) on background nusinersen started earlier in life ( < 5 years of age ) , treatment with apitegromab 20 mg / kg led to sizeable increases in HFMSE . o Mean increase from baseline was +7.1 points . o 88 % ( 7/8 ) of patients improved ( attained a ≥1 - point increase ) . 。 63 % ( 5/8 ) of patients attained a ≥5 - point increase . o 38 % ( 3/8 ) of patients attained a > 10 - point increase . • Patients had received approximately two years of prior nusinersen treatment at the time of enrollment ( 5.4 mean maintenance doses ) and were in the chronic maintenance phase of nusinersen therapy during the TOPAZ trial . • In the non - ambulatory cohort of patients ( mean age 11.7 ) on background nusinersen started later in life ( ≥5 years of age ) , treatment with apitegromab 20 mg / kg led to an increase in HFMSE , contrasting with declines experienced on average by this patient population without treatment . • Mean increase from baseline was +0.6 points by intent - to - treat analysis and +1.2 points by per - protocol analysis . • 64 % ( 9/14 ) of patients improved ( attained a ≥1 - point increase ) . o 29 % ( 4/14 ) of patients attained a ≥3 - point increase . • Patients had received approximately two years of prior nusinersen treatment at the time of enrollment ( 5.1 mean maintenance doses ) and were in the chronic maintenance phase of nusinersen therapy during the TOPAZ trial . • A post - hoc analysis across all non - ambulatory patients showed no correlation between change in HFMSE score at 12 months and duration of prior nusinersen therapy , providing further evidence that improvements in motor function may be