학술논문
A Phase I/Ib Trial of the VEGFR-Sparing Multikinase RET Inhibitor RXDX-105
Document Type
article
Author
Drilon, Alexander; Fu, Siqing; Patel, Manish R; Fakih, Marwan; Wang, Ding; Olszanski, Anthony J; Morgensztern, Daniel; Liu, Stephen V; Cho, Byoung Chul; Bazhenova, Lyudmila; Rodriguez, Cristina P; Doebele, Robert C; Wozniak, Antoinette; Reckamp, Karen L; Seery, Tara; Nikolinakos, Petros; Hu, Zheyi; Oliver, Jennifer W; Trone, Denise; McArthur, Katherine; Patel, Rupal; Multani, Pratik S; Ahn, Myung-Ju
Source
Cancer Discovery. 9(3)
Subject
Language
Abstract
RET fusions are oncogenic drivers of various tumors, including non-small cell lung cancers (NSCLC). The safety and antitumor activity of the multikinase RET inhibitor RXDX-105 were explored in a phase I/Ib trial. A recommended phase II dose of 275 mg fed daily was identified. The most common treatment-related adverse events were fatigue (25%), diarrhea (24%), hypophosphatemia (18%), maculopapular rash (18%), and nonmaculopapular rash (17%). In the phase Ib cohort of RET inhibitor-naïve patients with RET fusion-positive NSCLCs, the objective response rate (ORR) was 19% (95% CI, 8%-38%, n = 6/31). Interestingly, the ORR varied significantly by the gene fusion partner (P < 0.001, Fisher exact test): 0% (95% CI, 0%-17%, n = 0/20) with KIF5B (the most common upstream partner for RET fusion-positive NSCLC), and 67% (95% CI, 30%-93%, n = 6/9) with non-KIF5B partners. The median duration of response in all RET fusion-positive NSCLCs was not reached (range, 5 to 18+ months). SIGNIFICANCE: Although KIF5B-RET is the most common RET fusion in NSCLCs, RET inhibition with RXDX-105 resulted in responses only in non-KIF5B-RET-containing cancers. Novel approaches to targeting KIF5B-RET-containing tumors are needed, along with a deeper understanding of the biology that underlies the differential responses observed.This article is highlighted in the In This Issue feature, p. 305.