Repligen has announced positive results from the Phase 1 study of RG3039, a small molecule drug candidate for the treatment of spinal muscular atrophy (SMA).

The Phase 1 trial is a blinded ascending single dose study that involved 32 healthy volunteers to investigate the pharmacokinetic (PK) and safety profile of RG3039.

The study data demonstrates that RG3039 was well-tolerated at all doses administered and also reported evidence of a dose-related drug response resulting in 90% inhibition of the target enzyme.

Repligen president and chief executive officer Walter Herlihy said that the safety and PK outcomes from the Phase 1 study of RG3039 are encouraging, and the company looks forward to initiating the next steps for the drug candidate in alignment with guidance from the US Food and Drug Administration.

"The agency has previously granted Orphan Drug and Fast Track designations to RG3039, in recognition of the unmet medical need that exists for patients with SMA and the urgency to advance a treatment for this devastating disease," Herlihy added.

RG3039 is an orally bioavailable small molecule inhibitor of an RNA processing enzyme called DcpS, and has been shown to increase production of survival motor neuron (SMN) protein in cells derived from SMA patients.

Previous preclinical studies also showed that administration of RG3039 resulted in considerable improvements in survival and motor behaviour, as well as increased maximum body weight in severe SMA mice.

The Phase I study of RG3039 has been partially supported by a grant from the Muscular Dystrophy Association (MDA).

RG3039 has been granted orphan drug and fast track designations in the US as well as orphan medicinal product designation in the EU for treating SMA.

Spinal muscular atrophy is an autosomal recessive neuromuscular disease in which a defect in the SMN1 gene results in low levels of SMN protein, thereby leading to progressive damage to motor neurons.