According to investigators from the CheckMate 436 trial, Nivolumab plus brentuximab vedotin may be a new treatment option for patients with relapsed/refractory primary mediastinal large B-cell lymphoma (PMBCL). Interim results from this phase 1/2 trial revealed an overall response rate of 70%, including a complete response rate of 27%.

“It’s very promising … to see this level of activity in this advanced, relapsed/refractory population,” said Joseph E. Eid, MD, senior vice president of Bristol-Myers Squibb, which is sponsoring CheckMate 436 in collaboration with Seattle Genetics.

These results were presented as a poster at the annual meeting of the American Society of Hematology.

Dr. Eid noted that patients with relapsed or refractory PMBCL have limited treatment options. “The initial therapy works well in 70% to 80% of patients but the patients who fail don’t have good options,” he said.

Prior research has shown that PMBCL is often characterized by overexpression of the PD-1 ligands PD-L1 and PD-L2, and most PMBCL expresses CD30. Dr. Eid said CheckMate 436 (NCT02581631) was designed to “take advantage” of these characteristics by employing the anti-PD-1 checkpoint inhibitor nivolumab and the anti-CD30 antibody-drug conjugate brentuximab vedotin.

The median number of prior therapies was two and 13% of patients had prior autologous stem cell transplant.

The patients received nivolumab at 240 mg and brentuximab vedotin at 1.8 mg/kg every 3 weeks until progression or unacceptable toxicity.

At a median follow-up of 6.1 months, 10 patients were still on treatment. Reasons for discontinuation included maximum clinical benefit, disease progression, AEs unrelated to treatment, patient request, and other concerns.

The rate of treatment-related AEs was 83%. The most common of these were neutropenia (27%), peripheral neuropathy (20%), hyperthyroidism (13%), rash (10%), and thrombocytopenia (10%).

Grade 3-4 treatment-related AEs included neutropenia (27%), thrombocytopenia (7%), decreased neutrophil count (7%), hypersensitivity (3%), diarrhea (3%), and maculopapular rash (3%).

The rate of serious treatment-related AEs was 10%. This included grade 3-4 diarrhea and maculopapular rash and grade 5 acute kidney injury.

The acute kidney injury was the only fatal AE considered treatment related. There were three other deaths in the trial, but they were considered unrelated to treatment.

The complete response rate was 27% (n = 8), and the partial response rate was 43% (n = 13), for an overall response rate of 70% (n = 21).

“The early indication is that 70% response is a pretty good outcome in a relapsed/refractory population that, otherwise, their outcome is pretty dismal,” Dr. Eid said.

Ten percent of patients (n = 3) had stable disease, 13% (n = 4) progressed, and investigators were unable to determine the status for 7% of patients (n = 2).

The median time to response was 1.3 months, and the median time to complete response was 3.0 months. The median duration of response and complete response were not reached.