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Scholar Rock Scholar Rock Reports First Quarter 2021 Financial Results and Highlights Business Progress May 13 , 2021 - Apitegromab shows transformative potential in spinal muscular atrophy ( SMA ) with 74 % of patients with non - ambulatory Type 2 and 3 SMA in the TOPAZ Phase 2 trial attaining a clinical improvement in HFMSE at 12 months - Mean increase from baseline in HFMSE of 6.2 points ( across both evaluated doses ) observed in younger non - ambulatory patients ; up to 20 - point increases in HFMSE observed with 35 % of patients demonstrating a > 10 - point increase - Anticipate initiating apitegromab Phase 3 trial by year - end 2021 in patients with non - ambulatory Type 2 and 3 SMA , representing approximately 2/3 of SMA patient population - Dose escalation continues to progress in DRAGON Phase 1 trial evaluating SRK - 181 in combination with anti - PD- ( L ) 1 therapy ; initial data anticipated by year - end 2021 CAMBRIDGE , Mass .-- ( BUSINESS WIRE ) -- May 13 , 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 reported financial results for the first quarter ended March 31 , 2021 and highlighted recent progress and upcoming milestones for its pipeline programs . Company Updates and Upcoming Milestones Apitegromab is a selective inhibitor of myostatin activation being developed as the potential first muscle - directed therapy for the treatment of spinal muscular atrophy ( SMA ) . • TOPAZ 12 - Month Data Show Transformative Potential in SMA of Apitegromab as Add - on to SMN Upregulator Therapy . In April 2021 , positive top - line data were announced from the TOPAZ Phase 2 trial ( NCT03921528 ) in patients with Type 2 and Type 3 SMA . Both younger and older non - ambulatory patients treated with apitegromab and background SMN upregulator therapy over the 12 - month period attained meaningful motor function improvements with 74 % ( 23/31 ) of patients demonstrating a clinical improvement of ≥1 - point increase in Hammersmith Functional Motor Scale Expanded ( HFMSE ) . o In the younger non - ambulatory TOPAZ cohort ( ages 2-6 years ) , treatment with apitegromab led to a mean increase from baseline in HFMSE of +6.2 points across both evaluated doses ; a mean increase of +7.1 points for the 20 mg / kg dose and +5.3 points with the 2 mg / kg dose . Increase in HFMSE from baseline across both apitegromab doses : - 82 % ( 14/17 ) of patients attained a ≥1 - point increase - 59 % ( 10/17 ) of patients attained a > 3 - point increase - 59 % ( 10/17 ) of patients attained a > 5 - point increase - 35 % ( 6/17 ) of patients attained a > 10 - point increase o In the older non - ambulatory TOPAZ cohort ( age 8-19 years ) , treatment with apitegromab 20 mg / kg led to a mean increase from baseline in HFMSE of +0.6 points by the primary intent - to - treat analysis and +1.2 points by the prespecified per protocol analysis . Increase in HFMSE from baseline for this patient population : - 64 % ( 9/14 ) of patients attained a ≥1 - point increase - 29 % ( 4/14 ) of patients attained a > 3 - point increase Patients enrolled in TOPAZ were receiving chronic maintenance doses of nusinersen ; both the younger and older non - ambulatory cohorts had received more than five mean maintenance doses of nusinersen ( approximately two 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 experience 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 , older patients ( age 5-12 ) on average experience declines in HFMSE and rarely attain a 23 - point increase in HFMSE in a 12 - month timeframe.3 The five most frequently reported treatment - emergent adverse events included headache , pyrexia , upper respiratory tract infection , cough , and