Clinical-stage biopharmaceutical company Scholar Rock has started patient dosing in Topaz, a Phase II proof-of-concept trial of SRK-015 in Type 2 and Type 3 spinal muscular atrophy (SMA).
SRK-015, which is a selective inhibitor of the activation of myostatin, is an investigational product candidate for the treatment of patients with SMA.
Scholar Rock said interim results from the Phase I trial in healthy volunteers demonstrated favorable safety and tolerability, pharmacodynamic (PD), and pharmacokinetic (PK) results, as well as preclinical data that confirm the potential of myostatin as a drug target in SMA.
The Phase II trial will assess the safety and efficacy of SRK-015 dosed intravenously every four weeks over a 12-month treatment period either as a monotherapy or in conjunction with an approved SMN upregulator therapy.
About 55 patients with Type 2 or Type 3 SMA are expected to be enrolled in the US, Canada, and Europe across three distinct and parallel cohorts.
The company will make an interim analysis for each cohort, featuring a subset of patients with at least six months of treatment exposure.
The interim results by cohort are anticipated in the first half of 2020, while top-line results for the full 12-month treatment period are expected in the fourth quarter of 2020 and the first quarter of 2021.
Analyses of preliminary PK and PD data from a subset of patients are expected by the end of 2019.
Scholar Rock chief medical officer Yung Chyung said: “The initiation of patient dosing in our Phase II TOPAZ study marks an important milestone towards our goal of establishing SRK-015 as the first muscle-directed therapy to help address the functional deficits that continue to affect patients with SMA despite available therapies.
“Results from this Phase II trial will further our understanding on the potential clinical benefits of targeting the latent form of myostatin and open up the possibility of investigating other neuromuscular disorders.”
SRK-015 has secured orphan drug status in the US and orphan medicinal product designation in Europe. It has not been approved for any use across the world.