08 July 2019

New data regarding the novel drug, Hu5F9, has been presented at the 24th Congress of the European Hematology Association.

Hu5F9 is a humanised IgG4 isotype monoclonal antibody that is considered to be a macrophage immune checkpoint inhibitor which targets the so called ‘do not eat me’ signal. This in turn protects malignant tumour cells in lymphoma and has shown potentially long-lasting effects in relapsed and/or refractory lymphoma patients. The drug being developed by Forty Seven Inc. showed encouraging Phase 1b data when combined with rituximab (an anti-CD20 monoclonal antibody) in patients with r/r diffuse large B-cell lymphoma (DLBCL) and patients with follicular lymphoma when combined with rituximab.

These two agents work in combination to overcome the overexpressed protein CD47 whilst 5F9 targets the CD47 signal and rituximab steers it to sensitise lymphoma cells only. Findings presented from both phase 1b and phase 2 studies at the meeting reported data on a total of 70 patients with DLBCL and 45 patients with indolent lymphoma, including 41 patients with follicular lymphoma and 4 patients with marginal zone lymphoma. Patients were administered doses of the new drug in doses up to 45 mg/kg, in combination with rituximab, which was found to be well tolerated, with most adverse events classified as Grade 1 or 2. The overall response rate for the combination was 45%, with a rate of 36% for the 59 patients with DLBCL and 61% for the 38 patients with indolent lymphoma. The corresponding complete response rates were 19% for the overall patient population, 15% in DLBCL, and 24% in indolent lymphoma. Similar responses were observed across multiple DLBCL subtypes and patients with primary refractory lymphoma. The median time to response in the phase 1b and phase 2 cohorts was rapid, occurring in just 1.8 months (range 1.6–7.3 months).

It is still early days for this novel drug but the response in patients is encouraging and moving forward, combinations in future studies with other drugs in addition to rituximab are likely. https://www.medscape.com/viewarticle/914593