LUGANO, SWITZERLAND (FRONTLINE MEDICAL NEWS) – The immune checkpoint inhibitor avelumab showed efficacy against classical Hodgkin lymphoma among patients with disease progression following allogeneic stem cell transplants (allo-SCT), based on results of a phase 1 trial.

Two of eight patients with disease progression following an allogeneic transplant (allo-SCT) had complete responses (CR) to the programmed death ligand-1 (PD-L1) inhibitor avelumab (Bavencio), three had partial responses (PRs), and two had stable disease, reported Robert Chen, MD , of City of Hope Medical Center in Duarte, California.

“The overall response rate observed in the postallo population of 62.5% suggests that the PD-L1 blockade inhibitor may potentiate a graft-vs.-lymphoma response,” he said at the 14th International Conference on Malignant Lymphoma.

Amplification of the chromosome 9p24.1 locus is frequent in classical Hodgkin lymphoma, and the amplicon contains the genes encoding for PD-L1 and PD-L2, resulting in the over expression of both ligands, Dr. Chen said.

Both nivolumab (Opdivo) and pembrolizumab (Keytruda) are indicated for the treatment of relapsed/refractory classical Hodgkin lymphoma. Both agents block the interactions between PD-1 and both PD-L1 and PD-L2.

“However, it has not been established whether blockade of the PD-1/PD-L1 interaction is necessary and/or sufficient for the therapeutic effect observed in classical Hodgkin lymphoma,” he said.

Avelumab is an anti–PD-L1, immunoglobulin G1 monoclonal antibody that inhibits PD-1/PD-L1 interactions but leaves PD-1/PD-L2 interactions intact. This agent, which recently received FDA approval for the treatment of Merkel cell carcinoma and locally advanced or metastatic urothelial carcinoma, targets tumor cells rather than the T cells targeted by nivolumab and pembrolizumab.

In the phase 1b JAVELIN Hodgkin study , patients with histologically confirmed relapsed/refractory classical Hodgkin lymphoma who were ineligible for transplant or for whom allogeneic or autologous stem cell transplants had failed were enrolled and were assigned to one of five cohorts to receive avelumab in doses ranging from 70 mg intravenously to 10 mg/kg IV every 2 weeks (or every 3 weeks for the 500 mg dose cohort).

A total of 31 patients were randomized in the dose-finding phase of the study. The median patient age was 38 years, 24 patients were younger than 65, and 7 were 65 or older. Only 1 of the 31 patients had received a single prior line of therapy. Of those, 3 had received two prior therapies, 7 had been treated with three prior lines, and 20 had four or more prior lines of therapy. All patients had received brentuximab vedotin (Adcetris).

The median follow-up was 43.3 weeks. In all, nine patients were continuing on avelumab at the time of the data analysis. Because of disease progression, 10 patients discontinued therapy. Additionally, four discontinued because of adverse events, two chose to withdraw, one was removed from the study by the treating physicians, one did not receive treatment, and four others discontinued because of unspecified reasons.

The median treatment duration was 16.9 weeks. The mean number of cycles was 8.6.

The objective response rate was 42%, including five CRs and eight PRs. Three of the CRs were in patients treated at the 70 mg every 2 week dose, and two were in patients treated at the 500 mg every 3 week level.

In all, 23 patients experienced some degree of tumor shrinkage, and 13 had shrinkage greater than 50%.

In an analysis of best overall response among patients whose disease progressed following SCT, the investigators found that two of eight patients (25%) who had disease progression following allo-SCT had a complete response. Three of these patients had a PR, two had stable disease, and one was not eligible for response evaluation.

In contrast, there was only one objective response, a PR, among five patients who had relapses following autologous SCT.

Grade 3 or 4 treatment-related adverse events occurred in 37% of patients. There were no treatment-related deaths. The incidence of treatment-related adverse events was similar across the five dosing cohorts.

“Based on the observed efficacy and safety profiles and unmet need, this study has recently been amended to focus the expansion of patients who progressed post allo-SCT,” Dr. Chen said.

The study was sponsored by Pfizer in collaboration with Merck KGaA, Germany. Dr. Chen has consulted and served in a speakers’ bureau for Seattle Genetics, Millennium, and Genentech. He has also received research funding from Pharmacyclics, Seattle Genetics, Millennium, and Merck.