Phase II multicohort study of atezolizumab monotherapy in multiple advanced solid cancers

Area of Science:

• Oncology
• Immunotherapy
• Clinical Trials

Background:

• Atezolizumab, a programmed death-ligand 1 inhibitor, has demonstrated clinical activity in advanced cancers.
• This study evaluated atezolizumab monotherapy in various advanced solid tumors.

Purpose of the Study:

• To assess the efficacy and safety of atezolizumab in patients with advanced solid tumors.
• To determine the non-progression rate (NPR) at 18 weeks as a primary endpoint.

Main Methods:

• Phase II, open-label, basket study (NCT02458638) enrolling patients aged ≥18 years with stage III or IV solid tumors.
• Atezolizumab 1200 mg IV every 3 weeks until loss of benefit or toxicity.
• Primary efficacy endpoint: non-progression rate (NPR) at 18 weeks; NPR ≥40% defined as success.

Main Results:

• 474 patients enrolled; 433 in efficacy set. Enrollment stopped early due to slow recruitment and limited interim efficacy.
• NPR >20% observed in cervical cancer (44.4%), follicular/papillary thyroid cancer (54.5%), thymoma (76.9%), and GEP/lung neuroendocrine tumors (NETs) (41.7% and 58.3%).
• Treatment-related adverse events in 55.3% of patients; Grade 3-5 events in 10.3%, 1.7%, and 0.4% respectively.

Conclusions:

• Atezolizumab monotherapy showed effectiveness in cervical cancer.
• Interim benefit observed in thyroid cancer, thymoma, and GEP/lung NETs, but study termination prevented confirmation.
• Safety profile consistent with prior atezolizumab studies.