Atezolizumab induces durable responses in advanced alveolar soft part sarcoma
Click Here to Manage Email Alerts
Key takeaways:
- Atezolizumab monotherapy induced objective responses in more than one-third of patients.
- No treatment-related grade 4 or 5 adverse events occurred.
Atezolizumab induced durable responses among more than one-third of patients with advanced alveolar soft part sarcoma, according to data published in The New England Journal of Medicine.
In December, the FDA approved atezolizumab (Tecentriq, Genentech) — an anti-PD-L1 monoclonal antibody — for use by adults and children aged 2 years or older with unresctable or metastatic alveolar soft part sarcoma.
“The results of this phase 2 clinical study, which formed the basis of the recent FDA approval, support the use of atezolizumab as a safe and effective treatment for advanced [alveolar soft part sarcoma],” Alice P. Chen, MD, primary investigator with NCI, and colleagues wrote. “Further investigation is needed to inform clinical decisions regarding the duration of atezolizumab treatment, the usefulness and appropriate timing of treatment breaks, and the potential benefit of atezolizumab rechallenge after disease progression.”
Background and methodology
Alveolar soft part sarcoma — a rare soft-tissue sarcoma with a typically poor prognosis — has no established treatment. However, immune checkpoint inhibitors have shown early promising responses, according to researchers.
Chen and colleagues conducted a single-arm multicenter phase 2 study of atezolizumab for 52 patients (50% male; 52% white) with advanced alveolar soft part sarcoma. The cohort included 49 adults (median age, 33 years; range, 18-70) and three children (age range, 12 to 17 years).
Adults received IV atezolizumab at a dose of 1,200 mg every 21 days. Pediatric patients received atezolizumab dosed at 15 mg/kg — for a maximum 1,200 mg — every 21 days.
Objective response, duration of response and PFS served as the study’s main endpoints.
Results
Median follow-up was 13.2 months (range, 1.8-58).
Nineteen patients (37%) responded to treatment. One patient achieved complete response and 18 achieved partial responses.
Investigators reported median time to response of 3.6 months (range, 2.1-19.1), median response duration of 24.7 months (range, 4.1-55.8) and median PFS of 20.8 months.
Seven patients (13%) took treatment breaks after 2 years of therapy (duration range, 0.4 months to 25.3 months) but they maintained responses through the data-cutoff date.
Most study participants (96%) experienced at least one grade 1 or grade 2 adverse event. Researchers observed no treatment-related grade 4 or grade 5 events, and no study participants discontinued treatment due to adverse events.
Next steps
This study demonstrates the effectiveness of atezolizumab monotherapy for patients with this rare cancer, according to researchers.
“On the basis of these encouraging results, we are currently evaluating the addition of VEGF inhibition to PD-L1 blockade in patients who had disease progression during atezolizumab monotherapy in the present study,” they wrote. “The incidence of response and immune landscapes that we observed with atezolizumab monotherapy suggest that the addition of a VEGF inhibitor may not be necessary in first-line treatment.”
Collapse
Read more about
Click Here to Manage Email Alerts