The US Food and Drug Administration (FDA) has placed a partial clinical hold on Alpine Immune Sciences’ NEON-2 clinical trial of davoceticept (ALPN-202) plus pembrolizumab to treat advanced malignancies in adult patients.

The latest development comes after the company reported the death of a trial subject, a Grade 5 serious adverse event in this trial, which began in June last year. 

Alpine noted that the patient had choroidal melanoma, which was earlier treated with nivolumab plus ipilimumab, and also received one dose each of davoceticept and pembrolizumab. 

The death of the trial subject was attributed to cardiogenic shock, which the physicians suspected to be linked to immune-mediated myocarditis, or infection.

Subjects who are presently enrolled in the trial will be given davoceticept plus pembrolizumab but no additional patients will be enrolled until the FDA lifts partial clinical hold. 

Alpine Immune Sciences executive chairman and CEO Mitchell Gold said: “We appreciate the dialogue with FDA and look forward to working diligently with FDA, Merck, the study Safety Monitoring Committee, and the study investigators to further understand this unfortunate event. 

“Given the strong scientific rationale for the combination of davoceticept and pembrolizumab to benefit treatment-refractory patients, we are hopeful that the study will soon be resumed after appropriate safety review, and with appropriate safety precautions in place.”

The clinical hold will not affect another trial, NEON-1, which is underway to analyse davoceticept as a single agent in advanced malignancy patients, the company noted.

The dose-escalation completion and commencement of expansion cohorts in this trial are planned to begin in the first half of this year. 

A conditional CD28 costimulator and dual checkpoint inhibitor, davoceticept could potentially treat cancer.