BARCELONA – Atezolizumab (Roche's Tencentriq) improved overall survival in non-small cell lung cancer (NSCLC) patients with high PD-L1 expression when compared to chemotherapy, an interim analysis of the IMpower110 study has found.
David Spigel, chief scientific officer and lung cancer program director at Sarah Cannon Research Institute, presented the data at the annual meeting of the European Society for Medical Oncology in Barcelona today. He said the interim analysis showed that atezolizumab "represents a promising first-line treatment" for this patient population.
Anti-PD-1 monotherapy or PD-L1/PD-1 inhibitors in combination with chemotherapy are the current first-line treatments recommended for advanced NSCLC. IMpower110 is a Phase III, randomized, open-label study evaluating the efficacy of atezolizumab monotherapy as a first-line treatment in patients whose tumors express PD-L1, regardless of tumor histology, compared with cisplatin or carboplatin and pemetrexed or gemcitabine chemotherapy.
The study's primary endpoint is overall survival (OS) by PD-L1 subgroup, and key secondary endpoints include investigator-assessed progression-free survival (PFS), objective response rate (ORR), and duration of response (DoR). The researchers measured the expression of PD-L1 in the tumors, labeling the tumors with the highest expression (50 percent or more) TC3, tumors with medium levels of expression (5 percent or more) TC2/3, and tumors with low levels of expression (1 percent or more) TC1/2/3. PD-L1 expression was measured using the Ventana PD-L1 SP142 assay.
The 555 patients in the study were newly diagnosed with stage IV NSCLC, and they were randomized to receive atezolizumab or chemotherapy. TC3 patients in the atezolizumab arm had a median OS of 20.2 months compared to a median OS of 13.1 months for patients on chemotherapy, Spigel said, adding that "the benefit favored atezolizumab across the patient subgroups."
The researchers also saw an improvement in OS for TC2/3 patients, who exhibited median OS of 18.2 months with atezolizumab compared with a median OS of 14.9 months with chemotherapy. The patients in the TC1/2/3 group saw a median survival of 17.5 months with atezolizumab compared to 14.1 months for chemotherapy. Spigel noted that the difference in the TC1/2/3 group isn't statistically significant yet, but that the trend is encouraging — the researchers will continue to look at patients with lower levels of PD-L1 expression throughout the rest of the study.
Spigel further reported that PFS for TC3 patients was better with atezolizumab compared to chemotherapy — 8.1 months and 5.0 months, respectively — and said that PFS was also better in the other patient groups with atezolizumab, but that the difference was not yet statistically significant. There was also no appreciable difference in response rates between the two groups, he added.
Roche said it plans to submit the data to the US Food and Drug Administration and the European Medicines Agency. Spigel also noted that he plans to present data at future meetings on the efficacy of atezolizumab in patients measured for PD-L1 using Agilent's PD-L1 IHC 22C3 pharmDx diagnostic test and on Ventana's PD-L1 SP263 assay, and using blood tumor mutational burden as a biomarker.
In a discussion of the interim results, Columbia University Irving Medical Center's Naiyer Rizvi said that although there is more study needed for atezolizumab in patients with medium or low expression of PD-L1, the study has clearly shown that "atezolizumab in TC3 first-line NSCLC patients is a new standard of care," in addition to pembrolizumab (Merck's Keytruda) in PD-L1-expressing tumors.