Analyzing depth of response could help predict clinical outcomes in patients with unresectable or metastatic melanoma treated with targeted kinase inhibitors or immunotherapies, suggested findings presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.1

In the study, researchers from the US Food and Drug Administration looked at 10 randomized controlled trials conducted in patients with unresectable or metastatic melanoma treated with targeted kinase inhibitors, immunotherapy, or chemotherapy. (The patients in the study had not previously undergone any other treatment for their condition.)

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The investigators evaluated the patients’ data for depth of response, which they categorized into 4 groups based on maximal tumor shrinkage: G0 for “no shrinkage or increase,” G1 for shrinkage of at least 25% but less than 26%, G2 for shrinkage of 26% to 50%, G3 for shrinkage of 51% to 75%, G4 for shrinkage of 76% to less than 100%, and G5 for total (100%) shrinkage. The researchers then evaluated the link between depth of response and overall survival.

Based on data from 3778 patients who were evaluable for response, the researchers concluded that a larger depth of response was related to a longer overall survival — irrespective of the therapy that was used.

Among patients with a response of above 75% — spanning categories G4 and G5 — estimated overall survival at 2 years was high, at 69% in the targeted kinase inhibitor group and 92% in the immunotherapy group; however, a number of patients were censored, the presenters noted. And, for patients with at least a 50% depth of response to immunotherapies, PFS appeared to eventually plateau (in contrast to the trend seen in individuals who got TKIs).

Similarly, a greater depth of response was linked to a longer progression-free survival, the researchers found.

“Based on these results, we concluded that that depth of response correlates with both a longer progression-free and overall survival regardless of therapy type,” said study author Christy Osgood, MD, a medical officer at the FDA in Baltimore, Maryland. “Analysis of depth of response may provide a more nuanced prediction of clinical outcome for new therapeutics and combinations for the treatment of metastatic melanoma.”

Reference

  1. Osgood C, Mulkey F, Mishra-Kalyani PS, et al. FDA analysis of depth of response (DpR) and survival across 10 randomized controlled trials in patients with previously untreated unresectable or metastatic melanoma (UMM) by therapy type. Presented at 2019 American Society of Clinical Oncology (ASCO) Annual Meeting; May 31-June 4, 2019; Chicago, IL. Abstract 9508.

This article originally appeared on Cancer Therapy Advisor