Overviewing Phase 2 SYNAPSE-SMA Trial of NMD670 for Spinal Muscular Atrophy: Jorge Quiroz, MD, MBA

WATCH TIME: 5 minutes

"Because we’re at a proof-of-concept stage, we’ve decided to focus on this very homogenous population. This was based on our opinion and the opinion of other experts in the field. It’s possible that non-ambulatory patients will also receive the benefit, but for this first study, we’ve decided that focusing on SMA Type 3 ambulatory patients may be a good starting point."

Despite recent breakthroughs in the treatment of spinal muscular atrophy (SMA), preclinical and clinical studies have indicated that in addition to motor neuron degeneration, the transmission of signals from nerve to muscle is dysfunctional in SMA and that this transmission deficit may persist. Several industry leaders, including NMD Pharma, have begun to look into drugs that facilitate neuromuscular transmission. The company’s investigational agent, NMD670, is a first-in-class neuromuscular transmission enhancer working through selective inhibition of the skeletal muscle CIC-1 chloride ion channel.

In September 2023, the company announced the first patient dosing in its phase 2 SYNAPSE-SMA trial (NCT05794139) assessing NMD670 in ambulatory adults with SMA Type 3, also considered juvenile-onset SMA. SYNAPSE-SMA, a randomized, double-blind, placebo-controlled, 2-way crossover study, will test the efficacy, safety, and tolerability of twice-a-day oral dosing of NMD670 for 21 days. Prior to the study, the therapy demonstrated positive clinical study results in a phase 1/2 study in patients with myasthenia gravis (MG). The trial, published in Neuromuscular Disorders in 2023, represented the first proof-of-mechanism for CIC-1 inhibition in MG, a chronic autoimmune disorder.

Months later, at the 2024 Muscular Dystrophy Association (MDA) Clinical and Scientific Conference, held March 3-6, in Orlando, Florida, NeurologyLive® caught up with Jorge Quiroz, MD, MBA, chief medical officer of NMD Pharma, to discuss SYNAPSE-SMA. In the interview, he gave the clinical audience an overview of the trial design, the doses tested, and how patients will be randomized. Furthermore, he spoke on the reasons for using SMA Type 3, and why NMD670 could still have an effect in other SMA subtypes.

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REFERENCES
1. Quiroz J, Ruijs T, Gronnebaek TS, et al. NMD670, a novel first-in-class muscle CIC-1 inhibitor, improves symptoms of myasthenia gravis: a randomized, single-dose, double-blind, placebo-controlled study. Neuromusc Disord. 2023;33(S178). doi:10.1016/j.nmd.2023.07.439.
2. Kiyasova V Gronnebaek TT, Cornwall C, et al. Design and status update on the SYNAPSE-SMA phase 2 trial of NMD670 in ambulatory adults with spinal muscular atrophy type 3. Presented at: MDA Clinical and Scientific Conference; March 3-6, 2024; Orlando, FL. POSTER S114