Eli Lilly and Company has announced that its phase 3 JUNIPER study evaluating Verzenio (abemaciclib), a cyclin-dependent kinase (CDK)4 and CDK6 inhibitor, as monotherapy in KRAS-mutated, advanced non-small lung cancer (NSCLC) did not meet its primary endpoint of overall survival (OS). However, an analysis of the secondary study endpoints of both progression-free survival (PFS) and overall response rate (ORR) showed evidence of monotherapy activity in the abemaciclib arm. In addition, the control arm showed a higher overall survival rate than expected based on historical data in this setting. Lilly will submit the data for presentation at a medical meeting in 2018.
"While the outcome is unfortunate for patients with KRAS-mutated, advanced lung cancer, we remain encouraged by the antitumor activity observed with abemaciclib in this form of lung cancer where few clinical advances have been achieved," said Levi Garraway, M.D., Ph.D., senior vice president, global development and medical affairs, Lilly Oncology.
Dr. Garraway added, "As we analyze secondary endpoints and explore specific patient subgroups in order to better evaluate the prospects for abemaciclib in NSCLC, we will continue to work with the oncology community to inform potential future treatment avenues for patients with KRAS-mutated advanced lung cancer. Moreover, we have several studies ongoing of rational combinations that include abemaciclib in non-small cell lung cancer and other malignancies. We look forward to seeing the results of these studies."
JUNIPER, a global phase 3, interventional, open-label study was designed to evaluate the efficacy and safety of abemaciclib versus erlotinib in patients with stage IV NSCLC with a detectable KRAS mutation, who have progressed after platinum-based chemotherapy and who may have received one additional systemic therapy. A total of 453 patients were randomized to receive 200 mg of abemaciclib orally twice a day on a continuous dosing schedule, every 12 hours or 150 mg of erlotinib administered at its approved dose and schedule until disease progression, death or unacceptable toxicity. The primary endpoint of the study was OS, with key secondary endpoints of safety, ORR, and PFS. The adverse events were generally consistent with previous studies of abemaciclib, with the most common adverse events being diarrhea, fatigue, decreased appetite, and nausea.
Verzenio (abemaciclib) is an inhibitor of CDK4 and CDK6, which are activated by binding to D-cyclins. In estrogen receptor-positive (ER+) breast cancer cell lines, cyclin D1 and CDK4 & 6 promote phosphorylation of the retinoblastoma protein (Rb), cell cycle progression, and cell proliferation.
Verzenio disrupts the cell cycle. Preclinically, Verzenio dosed daily without interruption as a single agent or in combination with antiestrogens resulted in reduction of tumor size. In vitro, continuous exposure to Verzenio inhibited Rb phosphorylation and blocked progression from G1 to S phase of the cell cycle, resulting in senescence and apoptosis (cell death). Inhibiting CDK4 & 6 in healthy cells can result in side effects, some of which may be serious. Clinical evidence also suggests that Verzenio crosses the blood-brain barrier.