ASCO 2017: Avelumab in metastatic castration-resistant prostate cancer (mCRPC)

Chicago, IL ( Avelumab, an anti-PD-L1 antibody, is one of the novel immune checkpoint inhibitors generating so much interest in the field of cancer therapy. With growing evidence for its efficacy in multiple solid malignancies, including its recent approval for the treatment of metastatic bladder cancer, there is an effort to assess these agents in the setting of castration-resistant prostate cancer.

As an extension of the JAVELIN Solid Tumor trial, which has been assessing avelumab in multiple solid tumor settings, this is primarily a phase 1, open-label, dose-escalation trial in patients with metastatic castration-resistant prostate cancer (mCRPC). Patients who had progression of disease (PD) on an androgen receptor antagonist (ARA) were enrolled and treated with 10 mg/kg of avelumab. Restaging scans were completed every 6 weeks to determine PD, which was the primary clinical endpoint.

A total of 18 patients (median age 67, starting PSA 11 ng/mL, majority with Gleason >= 8 disease) were included in the study. Some of the patients (3) had received prior chemotherapy (docetaxel).

Ultimately, avelumab treatment appeared to be safe and tolerable. Only 2 patients had grade 3 asymptomatic treatment related adverse events (amylase & lipase elevations).

With regards to clinical efficacy, 7 patients had stable disease (SD) > 24 weeks post treatment, while 6 patients had PD after first restaging scans at 6 weeks which was reconfirmed in a 2nd restaging scan at 12 weeks. PSA doubling time (PSADT) prior to avelumab was compared with PSADT after 3 months of treatment. Among 17 patients with available data, 3 patients had a prolonged PSADT (defined at 3 months), 7 patients had stable PSADT and 7 had decreased PSADT.

As early results suggest some clinical efficacy without significant toxicity, future studies are warranted. This study continues to recruit patients.

Presented By: Farhad Fakhrejahani, MD, National Cancer Institute at the National Institutes of Health, Bethesda, MD

Co-Authors: Ravi Amrit Madan, William L. Dahut, Marijo Bilusic, Fatima Karzai, Lisa M Cordes, Julius Strauss, Jeffrey Schlom, James L. Gulley

Institution(s): National Cancer Institute at the National Institutes of Health, Bethesda, MD; National Cancer Institute, Bethesda, MD; National Institutes of Health, Bethesda, MD; Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD

Written By: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
Twitter: @tchandra_uromd

at the 2017 ASCO Annual Meeting - June 2 - 6, 2017 – Chicago, Illinois, USA
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