Combination of everolimus and lu-177 PRRT in treatment of G1-2 neuroendocrine tumors (NET): Phase 1-2 study.

Abstract

386 Background: Everolimus and Lutetium-177 PRRT were approved as monotherapy. However, animal model research showed synergistic effect of the combination. The goal of this study is to assess the safety and efficacy of the combination in treatment of unresectable G1-2 NETs of all gastrointestinal, lung and pancreatic origins. Methods: This is a phase 1-2 study. Phase 1 part involves finding the maximum tolerating dose (MTD) of everolimus and accordingly to recommend dose for phase II part. Starting everolimus dose was 5 mg OD. Patients were treated concurrently with Lu-177 DOTATOC therapy at intervals of 8 weeks (+/-1 week) with average of 4 sessions. Sample size calculation was based on the expected response of the combination to be 30% with power of 80 and type 1 of .05, compared to the known response rate of everolimus alone of 5%. Primary end point is safety. Other end points include response rate, PFS and OS. Results: Eleven patients, with progressive disease, were enrolled. Characteristics are summarized in the table. Everolimus MTD was 10 mg once daily. However, dose was reduced to 5 mg OD in 3 patients and to 5 mg once every other day in 2 patients. Median number of sessions of Lu-177: 3 sessions, and median cumulative dose: 300 mci. Most common G1-2 toxicities: stomatitis (90.9%), Nausea (72.7%), Fatigue (63.6%), anorexia (36.4%), diarrhea (36.4%) and skin and nail changes (36.4%). G3 toxicities (36%) were infection, fatigue, pneumonitis and neutropenia. No grade 4 toxicities. Reasons of discontinuation were toxicity in 3 patients, progression in 3, stroke in 1 and due to interruption of therapy in 4 patients. ORR: 1 PD, 1 PR and 9 SD. At median FU of 18.9 months, 7 patients are still alive, 3 died, and 1 lost to FU. Median PFS: 23.3 months. Conclusions: Combination of Everolimus and the Lu-177 PRRT appear to be safe and effective. Four patients, due to strict compliance criteria in the study protocol, were removed from the study prematurely resulting in undertreatment. Larger and randomized studies are required to confirm such findings.[Table: see text]