GENEVA (FRONTLINE MEDICAL NEWS) – Immune checkpoint inhibitors may improve survival in patients with non–small cell lung cancer (NSCLC) and brain metastases compared with chemotherapy, without adding unacceptable toxicities, pooled analyses of clinical trials suggest.
Among 1452 patients with NSCLC treated with the programmed death ligand-1 (PD-L1) inhibitor atezolizumab (Tecentriq), rates of treatment-related serious adverse events (SAEs) were similar between patients with brain metastases at baseline and those without brain metastases, reported Rimas V Lukas, MD , from the University of Chicago.
A subanalysis of patients enrolled in the OAK trial, comparing atezolizumab with docetaxel in patients with NSCLC, showed that patients with baseline brain metastases randomized to atezolizumab had a near doubling in overall survival, compared with patients with brain metastases assigned to docetaxel.
“Overall, I think that these results support the investigation of atezolizumab in non–small cell lung cancer patients with CNS metastases,” Dr. Lukas said at the European Lung Cancer Conference.
Lung cancer accounts for about 40%-50% of all cases of brain metastases, and approximately 20%-40% of patients with advanced NSCLC will develop metastases, which are associated with poor overall survival, according to Solange Peters, MD , from the Centre Hospitalier Universitaire Vaudois in Lausanne, Switzerland, the invited discussant.
To evaluate the safety and efficacy of the PD-L1 inhibitor in patients with brain metastases at baseline, Lukas et al. looked at pooled safety data on patients enrolled in one of five treatment studies with atezolizumab – PCD4989g ; BIRCH, POPLAR , FIR , and OAK – and efficacy data from a subset of patients in OAK.
The pooled analysis included 1452 patients, 79 of whom (5%) had brain metastases at baseline. This analysis showed that, although there was a higher incidence of any neurological AE, treatment-related AE, or treatment–related neurologic AE among patients with brain metastases, treatment-related SAEs and treatment related neurological SAEs were similar between the two groups. The most common neurological AE was headache, reported by 8% of patients with metastases and 3% without.
The efficacy analysis, which included a cohort of the first 850 patients with or without brain metastases treated, showed a significant survival for atezolizumab in the OAK trial, with median overall survival of 20.1 months for patients with brain metastases assigned to the PD-L1 inhibitor, compared with 11.9 months for patients assigned to docetaxel. This translated into a hazard ratio for atezolizumab of 0.54 (P = .0279).
Among the 750 patients without baseline brain metastases in OAK, the respective OS rates were 13.0 months, vs. 9.4 months (HR, 0.75; P = .001).
Although it was not statistically significant, the risk for developing new central nervous system lesions also appeared to be lower with atezolizumab than with docetaxel, with a median time to new lesions not reached, vs. 9.5 months with docetaxel (HR, 0.42; 95% confidence interval, 0.15-1.18).
Among patients without baseline brain metastases, there was also a hint that atezolizumab could delay onset of CNS metastases, although the trend was not significant, the investigators found.
In her commentary on the study, Dr. Peters said that “checkpoint inhibitors demonstrate activity in the brain that remains to be quantified and prospectively compared to systemic activity in larger series, and these are very small series.”
“Limitations in duration and level of activity might exist, however, related to the blood brain barrier and the brain immune system characteristics,” she added.
The study was supported by F. Hoffmann-La Roche/Genentech, a member of the Roche Group. Dr. Lukas disclosed serving on advisory boards for AstraZeneca and Novocure and receiving honoraria from AbbVie. Two coauthors are employees of Genentech, and two are employed by Roche. The remaining author had no disclosures. Dr. Peters reported relationships with Bristol-Myers Squibb, F. Hoffmann-La Roche, Eli Lilly, AstraZeneca, Pfizer, Boehringer Ingelheim, Daiichi-Sankyo, Morphotek, Merrimack, Merck Sharp and Dohme, and Merck Serono.