Glofitamab Offers High Complete Response Rates for Relapsed or Refractory MCL

Patients with relapsed or refractory mantle cell lymphoma (MCL) may benefit from glofitamab monotherapy, according to research presented at the Eleventh Society of Hematologic Oncology Annual Meeting in Houston, Texas.

A multinational research team led by presenter Tycel Philips, MD, of the City of Hope in Duarte, California, shared phase I/II trial results that showed a 73% complete response (CR) rate, with manageable safety issues, from the use of glofitamab.

After obinutuzumab pretreatment was administered seven days before in doses of 1000 mg or 2000 mg, intravenous glofitamab was then administered with step-up dosing on day eight (2.5 mg) and 15 (10 mg) of cycle 1. Next, the target dose was given over 21-day cycles (16 mg or 30 mg after 1000 mg of obinutuzumab or 30 mg after 2000 mg of obinutuzumab).

Of the 37 patients who had received glofitamab as of March 14, 2022, 16 had 1,000 mg of obinutuzumab pretreatment and 21 had 2,000 mg of obinutuzumab treatment. In addition 91.9% had Ann Arbor stage III/IV disease.

The patients had a median of three prior lines of therapy, with a range of one to five. Furthermore, 24 (64.9%) had received prior Bruton tyrosine kinase inhibitor (BTKi) therapy and 33 (89.2%) were refractory to any prior therapy.

The overall response rate was 83.8% and the CR rate was 73% after the median follow-up of eight months. Also, the median time of CR was 51 days, and the duration was 10 months. What’s more, 74.1% of complete responders were ongoing at the data cutoff, according to the researchers.

As for adverse events (AEs), the most common was cytokine release syndrome (CRS), which occurred in 75.7% of the patients but with a lower incidence (66.7%) in the group of patients who received 2,000 mg of obinutuzumab.

However, all CRS events were deemed to be manageable and mainly low-grade; 17 patients were given tocilizumab and 29.7% of the events were grade 1 and 29.7% were grade 2. No patients discontinued treatment because of AEs.

“Fixed-duration glofitamab monotherapy induced high, durable CR rates in patients with [relapsed/refractory] MCL, including those with prior BTKi therapy. CRS events were manageable and mostly low-grade,” the authors wrote.

There were 10 deaths, but none were related to the study treatment, according to the researchers.

Reference

Philips T, Dickinson M, Morschhauser F, et al. Glofitamab monotherapy induces high complete response rates in patients with heavily pretreated relapsed or refractory mantle cell lymphoma. Abstract MCL-467. Presented at the Eleventh Annual Meeting of the Society of Hematologic Oncology; September 6-9, 2023; Houston, Texas.