The New England Journal of MedicineAtezolizumab for Advanced Alveolar Soft Part Sarcoma

The checkpoint inhibitor Tecentriq shows promise in treating the soft-tissue tumor.

In a landscape where treatment options for alveolar soft part sarcoma (ASPS) are limited and often ineffective, a recent phase 2 study on the use of atezolizumab offers a glimmer of hope. The study reveals that this immune checkpoint inhibitor can induce sustained responses in a significant proportion of patients with advanced ASPS.

HCN Medical Memo
For physicians treating patients with advanced ASPS, the study’s findings are encouraging. Atezolizumab has shown to induce sustained responses in approximately one-third of patients, with a favorable safety profile. This could potentially be a game-changer in the management of this rare and often fatal condition.

Study Design:

• Investigator-initiated, multicenter, single-group, phase 2 study
• Participants: 52 adult and pediatric patients with advanced ASPS
• Treatment: Atezolizumab administered intravenously every 21 days
• Dosing: 1200 mg for adults and 15 mg/kg with a 1200-mg cap for pediatric patients
• End Points: Objective response, duration of response, and progression-free survival, along with pharmacodynamic biomarkers

Alveolar soft part sarcoma (ASPS) accounts for less than 1% of all soft tissue sarcomas.

Key Findings:

• Objective response observed in 19 out of 52 patients (37%)
• One complete response and 18 partial responses recorded
• Median time to response: 3.6 months
• Median duration of response: 24.7 months
• Median progression-free survival: 20.8 months
• No grade 4 or 5 treatment-related adverse events
• Responses maintained even after a 2-year treatment break in 7 patients

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