Atezolizumab can induce response in alveolar soft part sarcoma

The immunotherapy agent atezolizumab induces sustained responses in about one-third of patients with advanced alveolar soft part sarcoma (ASPS), according to a study published in the Sept. 7 issue of the New England Journal of Medicine.

Alice P. Chen, M.D., from the National Cancer Institute in Bethesda, Maryland, and colleagues assessed response and progression-free survival in a phase 2 study of the anti-programmed death ligand 1 (PD-L1) drug atezolizumab in 52 adult and pediatric patients with advanced ASPS. Atezolizumab was administered once every 21 days at a dose of 1,200 mg for adults and 15 mg/kg for children.

The researchers found that 37 percent of the patients had an objective response, with one complete and 18 partial responses. The median time to response was 3.6 months and median response duration was 24.7 months. The median progression-free survival was 20.8 months in the cohort. After two years of treatment, seven patients took a treatment break; their responses were maintained through data cutoff. There were no treatment-related grade 4 or 5 adverse events. Despite variable baseline expression of programmed death 1 and PD-L1, responses were noted.

"The results of this phase 2 clinical study, which formed the basis of the recent U.S. Food and Drug Administration approval, support the use of atezolizumab as a safe and effective treatment for advanced ASPS," the authors write.