The following article features coverage from the Society of Immunotherapy of Cancer (SITC) 2020 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Nivolumab plus ipilimumab showed antitumor activity against angiosarcoma, according to the results of a phase 2 study presented at the virtual Society for Immunotherapy of Cancer 35th Anniversary Annual Meeting & Preconference Programs (SITC 2020).

Angiosarcoma is a rare disease with poor long-term survival among patients who develop metastases. Mutation patterns of angiosarcoma and case reports suggest that the disease may respond to immune checkpoint inhibitors.

“We sought to answer that question prospectively: Can immune checkpoint inhibitors benefit patients with angiosarcoma?” Michael J. Wagner, MD, of the Seattle Cancer Care Alliance in Seattle, Washington, and presenter of the study, said.

The phase 2 trial included 50 cohorts of patients with rare cancer types. The present analysis is of cohort 51, which included 16 patients with angiosarcoma. Patients were treated with nivolumab 240 mg every 2 weeks plus ipilimumab 1 mg/kg every 6 weeks. The primary endpoint was response and secondary endpoints included progression-free survival (PFS), overall survival (OS), and toxicity.


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At baseline, the median age of patients was 68 years, and 38% of patients were female. The primary site of disease included the breast, extremity, face/scalp, liver, heart, spleen, and stomach. The median number of prior therapies was 2 (range, 0-5).

The objective response rate was 25%, and occurred among patients with cutaneous disease of the face/scalp and patients with radiation-associated breast angiosarcoma.

The 6-month PFS was 38%. “There was a pretty steep drop off in that first 2-month period for patients who did not respond or have stable disease,” Dr Wagner said. Median OS has not yet been reached.

Molecular testing results was evaluable for 8 patients. Patients who responded to treatment had intermediate or high tumor mutation burden, and two-thirds of patients had tumors with high programmed cell death ligand 1 (PD-L1) expression.

Grade 3 to 4 toxicities occurred among 25% of patients and led to treatment discontinuation among 12.5%. There were no grade 5 events. Grade 3 to 4 immune-mediated toxicities occurred among 12.5% of patients, with the most common being elevated alanine or aspartate aminotransferase, and diarrhea.

The authors concluded that “ipilimumab and nivolumab is well tolerated and safe in patients with angiosarcoma.” They said that these results warrant a larger study in this population.

Disclosures: The presenter reported that research support from Deciphera, Adaptimmune, GlaxoSmithKline, Athenex, and Incyte was given to his institution, and he is on the advisory board for Deciphera and Adaptimmune.

Read more of Cancer Therapy Advisor‘s coverage of the SITC 2020 meeting by visiting the conference page.

Reference

Wagner MJ, Othus M, Patel SP, et al. A multicenter phase II trial (SWOG S1609, Cohort 51) of ipilimumab and nivolumab in metastatic or unresectable angiosarcoma: a sub-study of dual anti-CTLA-4 and anti-PD-1 blockade in rare tumors (DART). Presented at: Society for Immunotherapy of Cancer 35th Anniversary Annual Meeting & Preconference Programs (SITC 2020); November 11-14, 2020. Abstract 795. J Immunother Cancer. 2020;8(Suppl 3):A656–A959.