CHICAGO — Patients with metastatic non-small cell lung cancer (NSCLC) treated with anti-programmed cell death-1 (anti-PD-1) therapy generally do not benefit from treatment beyond RECIST-defined disease progression, according to study results presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting.1
“Anecdotal cases of decreases in tumor size after initial RECIST-defined disease progression have led to trials allowing treatment past RECIST-defined first progression,” lead investigator Dickran Kazandjian, MD, of the U.S. Food and Drug Administration (FDA), said.
Therefore, researchers sought to describe the findings of patients treated with anti-PD-1 monoclonal antibody therapy beyond disease progression in a trial of patients with metastatic NSCLC. The investigators hoped to gain insight into the FDA implications regarding regulatory end points and trial results, as well as implications for individual patients receiving treatment past progression.
For the study, investigators analyzed data from the trial, which involved 535 patients with metastatic NSCLC who progressed after platinum-doublet chemotherapy and demonstrated a clinical benefit from a PD-1 inhibitor. Patients were eligible to receive treatment beyond RECIST-defined disease progression if they were not experiencing rapid disease progression and had stable performance status. Of those, 121 received treatment beyond first progression and 414 did not.
Results showed that their best overall responses were progressive disease in 52%, stable disease in 33%, and partial response in 15%, which was similar among patients with and without treatment past progression.
“Patients who received treatment past progression initially progressed per RECIST due to unequivocal progression of non-target lesions (38%), the appearance of new lesions (32%), and an increase of ≥20% from the nadir in the sum of longest diameter of target lesions (30%),” Dr Kazandijan explained.
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Researchers found that only 8.3% of patients treated beyond disease progression experienced additional tumor shrinkage.
“Our retrospective exploratory analysis suggests that only a few patients (8%) receiving treatment past progression obtain a subsequent partial response, which represents only 1.9% of all patients receiving a PD-1 inhibitor,” Dr Kazandijan concluded. “Further randomized controlled trials are needed to prospectively establish benefit of treating patients past first progression for individual patients but these results would be unlikely to significantly change major FDA regulatory end point results or benefit/risk determination.”
- Kazandjian DG, Blumenthal GM, Khozin S, et al. Characterization of patients treated with a programmed cell death protein 1 inhibitor (anti-PD-1) past RECIST progression from a metastatic non-small cell lung cancer (mNSCLC) trial. J Clin Oncol. 2016; 34 (suppl; abstr 3000).