Phase 2 abemaciclib trial in patients with advanced NETs

Presented by

Prof. Kaylyn Kit Man Wong, University of Washington, USA

Conference

ASCO GI 2021

Trial

Phase 2

Prof. Kaylyn Kit Man Wong (University of Washington, USA) presented a trial-in-progress, the phase 2 trial investigating the CDK4/6 inhibitor abemaciclib in patients with advanced and refractory well‐differentiated gastroenteropancreatic neuroendocrine tumours (GEP NETs).

The rationale behind this study is that long‐term disease control of NETs remains a challenge, and although a number of preclinical studies have indicated proof-of-concept for CDK 4/6 inhibition in NETs in vitro and in vivo, there have been no prospective trials demonstrating efficacy. Specifically, the clinical use of selective small molecule CDK 4/6 inhibitor abemaciclib in some metastatic breast cancer subtypes has supported clinical efficacy, demonstrated good tolerability, and has demonstrated central nervous system penetration.

This phase 2 trial is accruing patients with metastatic or locally advanced unresectable well-differentiated grade 1-2 GEP NETs to receive abemaciclib (200 mg orally every 12 hours continuously in 28-day cycles). Patients must have progressed on ≥1 prior systemic therapy; somatostatin analogues can be concurrent or used previously. The primary endpoint is objective response rate (ORR) by RECIST v1.1. Secondary endpoints include progression-free survival (PFS), overall survival (OS), and toxicity. A 2‐stage design with 88% power to detect an increase in ORR to 20% with abemaciclib at the 1‐sided 0.05 level would require a total of 37 patients.

Stage 1 will include 20 patients. Of those, if at least 1 response is observed, the study will continue to enrol another 17 patients. To date, 3 patients have been enrolled in stage 1, and data collection is ongoing.

Wong KM, et al. Phase II trial of the CDK4/6 inhibitor abemaciclib in patients (pts) with advanced and refractory well‐differentiated gastroenteropancreatic neuroendocrine tumors (GEP NETs). ASCO Gastrointestinal Cancers Symposium 2021, 15-17 January. Abstract TPS376.

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