Mesoblast announces positive Phase 2 RA results

Company News

Mesoblast (ASX:MSB) has announced that a single intravenous infusion of its allogeneic Mesenchymal Precursor Cell (MPC) product candidate, MPC-300-IV, was well tolerated and demonstrated a dose-related improvement in clinical symptoms, physical function, and disease activity relative to placebo through the 12 week primary endpoint in its Phase 2 trial in biologic refractory rheumatoid arthritis.

Dr Allan Gibofsky, Professor of Medicine and Public Health at Weill Cornell Medical College and Attending Rheumatologist at Hospital for Special Surgery in New York, said: “The safety and efficacy results of this study are very encouraging and suggest that Mesoblast’s cell therapy has the potential to fill the major unmet medical need of the biologic refractory RA population, where agents that provide consistent durable effects without the risk of opportunistic infections or malignancies are sorely needed.”

Mesoblast’s Phase 2 trial recruited a total of 48 patients with active RA who were on a stable regimen of methotrexate and had an inadequate prior clinical response to at least one anti-Tumor Necrosis Factor (TNF) agent.

According to the company, of the 48 patients, 30 (63%) had previously received 1-2 biologic agents.

"Patients were randomized to a single intravenous infusion of 1 million MPCs/kg (1M/kg, n=16), 2 million MPCs/kg (2M/kg, n=16) or placebo (n=16)," it said. "The study was comprised of a 12 week primary study period with a 40 week follow-up for a study total duration of 52 weeks. The primary objective of the study was to evaluate safety and tolerability of a single intravenous MPC infusion in these biologic refractory RA patients through a 12 week primary endpoint."

Mesoblast said  patients who had previously received 1-2 biologics, a single infusion of 2 million MPC/kg resulted in 55 per cent and 36 per cent ACR50 and ACR70 responses, compared with 11 per cent and 0 per cent of placebo treated patients. In addition, 91 per cent of patients achieved the minimum clinically important improvement in physical function, defined as a reduction of at least -0.22 in the HAQ-DI, compared with 33 per cent  of patients treated with placebo.

Mesoblast Chief Executive, Silviu Itescu, said: “The Phase 2 trial results have indicated a strong efficacy signal and consistent effects of a single MPC infusion on clinical symptoms, functional abilities, and disease activity, without any serious adverse events. These results support the potential of our allogeneic cell therapy to be positioned as a first-line treatment option for biologic refractory patients, where there is a clear need for safe and effective treatments. Given the large market opportunity, our Tier 1 product candidate, MPC-300-IV, is well-positioned to advance through a strategic partnership into Phase 3 development for biologic refractory rheumatoid arthritis.”