Scholar Rock has raised $47 million to take its treatment for spinal muscular atrophy (SMA) into the clinic. The series C tees up Scholar Rock to find out whether its myostatin blocker can best the underwhelming performance of one-time rivals from companies including Novartis.

Cambridge, Massachusetts-based Scholar Rock specializes in conditions in which growth factors are key, a focus that positions it to target a wide range of diseases including cancers and fibrosis. The near-term focus is on neuromuscular conditions, specifically SMA. 

Scholar Rock is looking to SRK-015, an inhibitor of the supracellular activation of latent myostatin, to improve outcomes in this population by boosting muscle strength and motor function.

Companies including Novartis, Amgen spinout Atara and Shire have swung and missed at myostatin in recent years. Scholar Rock, which ceded a significant head start to these and other companies, has always maintained SRK-015’s targeting of upstream processes gives it an edge over the competition. And it and its investors’ belief in that idea has survived the clinical failures of other myostatin drugs.

New investor Invus led the series C. Redmile Group also came on board for the first time. The new investors were joined in the round by all the companies that drove Scholar Rock to a $36 million B round two years ago. That list includes Polaris Partners, Timothy Springer, ARCH Venture Partners, EcoR1 Capital and The Kraft Group.

The syndicate’s support gives Scholar Rock the means to start a phase 1 trial of SRK-015. Scholar Rock has taken longer than expected to reach this point. In 2015, the startup had its sights on a 2016 start date for the first clinical trial. Now, the goal is to get SRK-015 into humans some time in the next six months. 

Scholar Rock plans to test the drug as a monotherapy in subpopulations of SMA patients and more broadly in combination with drugs that upregulate production of SMN, a protein that is deficient in patients with SMA. Biogen’s Spinraza is such a drug.

The later-than-expected move into the clinic has given Scholar Rock time to branch out beyond its initial focus on neuromuscular diseases. Johnson & Johnson-partnered cancer candidates are making their way through target validation and discovery, as are in-house programs targeting fibrosis, autoimmune diseases and hematology. 

Scholar Rock plans to advance these programs using the series C proceeds. 

SRK-015 remains the drug that will define the near-term future of the company, though. And with another $47 million in the bank, Scholar Rock can now start generating clinical data to back up its belief a more specific, localized approach can unlock the potential of myostatin.