Exploratory analyses
Dr. Peters presented a slide showing tumor burden reductions occurring in responders. “What has to be concluded from this very interesting graph is that there are more, deeper responses in the NIVO-IPI versus chemotherapy. Very importantly, too, this is strongly correlated with survival. In both treatment arms, a high magnitude of tumor burden reduction is correlated with an improved survival,” said Dr. Peters. Specifically, among PD-L1 positive patients with more than 80% tumor reduction, survival was 59% at 6 years (95% CI, 44-71%). The figure was 68% in the NIVO only arm (95% CI, 47-82%), and 42% in the chemotherapy only arm (95% CI, 15-66%).
Among PD-L1 negative patients, “there are more, deeper responses in NIVO-IPI versus chemotherapy. That is very clear. And probably differently from the positive PD-L1 arm, the tumor burden reduction is correlated with survival but really only strongly observed in the NIVO-IPI arm,” said Dr. Peters. The figure was 20% in the nivolumab arm (95% CI, 3-48%) and 0% in the chemotherapy only arm (95% CI, not available). “So really something is correlating the tumor burden reduction with the outcome and specifically correlating it in the negative PD-L1 with the treatment of NIVO-IPI,” said Dr. Peters.
The researchers also noted longer progression-free survival and overall response rate in the NIVO-IPI group than the chemotherapy group in both PD-L1 positive and PD-L1 negative patients.
With respect to health-related quality of life, the researchers found a correlation between higher scores at baseline on the EQ-5D-3L scale and overall survival in the chemotherapy group (HR, 0.61; 95% CI, 0.51-0.74) and a trend in the NIVO-IPI group (HR, 0.83; 95% CI, 0.69-1.01). “So this baseline history, the quality of life, is correlated with the outcome regardless of the treatment you deliver,” said Dr. Peters.
Personalizing immunotherapy in NSCLC
In his comments, Dr. Skoulidis highlighted the length of responses. “Most importantly, approximately 50% of these patients that are alive at six years are also disease free, suggesting that we are indeed making a dent on the natural history of the disease for these patients,” he said.
He also made a case for personalizing immunotherapy and suggested that CheckMate 227 could provide some guidance. “Ipilimumab/nivolumab – the CheckMate 227 regimen – appears to be particularly active in terms of inducing long-term, long-lasting responses and overall survival in patients harboring tumors that are negative for PD-L1,” he said.
Dr. Skoulidis also highlighted the 16% six-year overall survival among PD-L1 negative patients who received NIVO-IPI, calling it “impressive.” Of those who responded, 25% continued to respond at 6 years. “This is particularly notable in the subset of patients with squamous histology and lack of PD-L1 expression, where the six year overall survival rate with NIVO-IPI versus chemo was 18% versus 4%. So perhaps in patients with squamous histology and lack of PD-L1 expression, NIVO-IPI might represent a favorable regimen to improve long term outcomes,” said Dr. Skoulidis.
CheckMate 227 was funded by Bristol Myers Sqiubb. Dr. Peters has financial relationships with a wide range of pharmaceutical companies, including Bristol Myers Squibb. Dr. Skoulidis has financial relationships with Moderna, BioNTech, Amgen, Intellisphere, Navire, BeiGene, Medscape, Calithera Biosciences, Tango Therapeutics, Guardant Health, Novartis, AIMM Therapeutics, Mirati Therapeutics, Boehringer Ingelheim, Merck, and Pfizer.