Multicenter phase II trial (SWOG S1609, cohort 51) of ipilimumab and nivolumab in metastatic or unresectable angiosarcoma: a substudy of dual anti-CTLA-4 and anti-PD-1 blockade in rare tumors (DART)

J Immunother Cancer. 2021 Aug;9(8):e002990. doi: 10.1136/jitc-2021-002990.


Purpose: Angiosarcoma is a rare aggressive endothelial cell cancer with high mortality. Isolated reports suggest immune checkpoint inhibition efficacy in angiosarcoma, but no prospective studies have been published. We report results for angiosarcoma treated with ipilimumab and nivolumab as a cohort of an ongoing rare cancer study.

Methods: This is a prospective, open-label, multicenter phase II clinical trial of ipilimumab (1 mg/kg intravenously every 6 weeks) plus nivolumab (240 mg intravenously every 2 weeks) for metastatic or unresectable angiosarcoma. Primary endpoint was objective response rate (ORR) per RECIST 1.1. Secondary endpoints include progression-free (PFS) and overall survival, and toxicity. A two-stage design was used.

Results: Overall, there were 16 evaluable patients. Median age was 68 years (range, 25-81); median number of prior lines of therapy, 2. Nine patients had cutaneous and seven non-cutaneous primary tumors. ORR was 25% (4/16). Sixty per cent of patients (3/5) with primary cutaneous scalp or face tumors attained a confirmed response. Six-month PFS was 38%. Altogether, 75% of patients experienced an adverse event (AE) (at least possibly related to drug) (25% grade 3-4 AE); 68.8%, an immune-related AE (irAE) (2 (12.5%), grade 3 or 4 irAEs (alanine aminotransferase/aspartate aminotransferase increase and diarrhea)). There were no grade 5 toxicities. One of seven patients in whom tumor mutation burden (TMB) was assessed showed a high TMB (24 mutations/mb); that patient achieved a partial response (PR). Two of three patients with PDL1 immunohistochemistry assessed had high PDL1 expression; one achieved a PR.

Conclusion: The combination of ipilimumab and nivolumab demonstrated an ORR of 25% in angiosarcoma, with three of five patients with cutaneous tumors of the scalp or face responding. Ipilimumab and nivolumab warrant further investigation in angiosarcoma.

Trial registration number: NCT02834013.

Keywords: Clinical Trials; Combination; Drug Therapy; Immunotherapy; Phase II as Topic; Sarcoma.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • CTLA-4 Antigen / antagonists & inhibitors*
  • Female
  • Hemangiosarcoma / drug therapy*
  • Hemangiosarcoma / pathology
  • Humans
  • Immune Checkpoint Inhibitors / administration & dosage
  • Ipilimumab / administration & dosage
  • Male
  • Middle Aged
  • Neoplasm Metastasis
  • Nivolumab / administration & dosage
  • Prospective Studies
  • Rare Diseases / drug therapy*
  • Rare Diseases / pathology


  • CTLA-4 Antigen
  • CTLA4 protein, human
  • Immune Checkpoint Inhibitors
  • Ipilimumab
  • Nivolumab

Associated data