Original Article

Pilot trial of CRLX101 in patients with advanced, chemotherapy-refractory gastroesophageal cancer

Joseph Chao, James Lin, Paul Frankel, Andrew J. Clark, Devin T. Wiley, Edward Garmey, Marwan Fakih, Dean Lim, Vincent Chung, Eloise Luevanos, Scott Eliasof, Mark E. Davis, Yun Yen


Background: CRLX101 is an investigational nanoparticle-drug conjugate with a camptothecin payload. Preclinical evidence indicated preferential uptake in tumors, and tumor xenograft models demonstrate superiority of CRLX101 over irinotecan. A pilot trial was conducted at recommended phase 2 dosing (RP2D) using the bimonthly schedule to assess preferential uptake of CRLX101 in tumor vs. adjacent normal tissue in endoscopically accessible tumors in chemotherapy-refractory gastroesophageal cancer. Results from the biopsies were previously reported and herein we present the clinical outcomes.
Methods: Patients initiated CRLX101 dosed at RP2D (15 mg/m2) on days 1 and 15 of a 28-day cycle. Detection of preferential CRLX101 tumor uptake was the primary endpoint and objective response rate (ORR) was a secondary endpoint. With a sample size of ten patients, the study had 90% power to detect ≥1 responder if the true response rate is ≥21%.
Results: Between Dec. 2012 and Dec. 2014, ten patients with chemotherapy-refractory (median 2 prior lines of therapy, range 1–4) gastric adenocarcinoma were enrolled. The median time-to-progression was 1.7 months. Best response was seen in one patient with stable disease (SD) for 8 cycles. Only ≥ grade 3 drug-related toxicity occurred in one patient with grade 3 cardiac chest pain who was able to resume therapy after CRLX101 was reduced to 12 mg/m2.
Conclusions: Bimonthly CRLX101 demonstrated minimal activity with SD as best response in this heavily pretreated population. Future efforts with CRLX101 in gastric cancer should focus on combination and more dose-intensive strategies given its favorable toxicity profile and evidence of preferential tumor uptake.

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