Dr. Shroff on Results of the SWOG 1815 Trial in Advanced Biliary Tract Cancers

Rachna T. Shroff, MD, MS, medical director, Clinical Trials Office, chief, Section of GI Medical Oncology, director, Arizona Clinical Trials Network, and the associate director of clinical investigations, Clinical and Translational Oncology Program, University of Arizona Cancer Center, discusses efficacy data from the phase 3 SWOG 1815 trial (NCT03768414) investigating nab-paclitaxel (Abraxane) plus gemcitabine and cisplatin compared with gemcitabine and cisplatin alone in newly diagnosed patients with advanced biliary tract cancers.

Findings presented at the 2023 ASCO Gastrointestinal Cancers Symposium showed that the addition of nab-paclitaxel to gemcitabine/cisplatin did not produce a statistically significant improvement in overall survival (OS) vs gemcitabine/cisplatin alone. The median OS for nab-paclitaxel plus gemcitabine/cisplatin was 14 months, compared with 12.7 months for gemcitabine/cisplatin alone. Patients treated with the triplet also experienced numerical improvement that was not statistically significant in median progression-free survival (PFS) at 8.2 months vs 6.4 for gemcitabine/cisplatin alone.

Patients in the nab-paclitaxel arm achieved an overall response rate (ORR) of 31%, compared with 22% for those in the control arm. However, the ORR data were also not statistically significant.

When looking at the trial’s prespecified stratification factors, investigators observed some interesting signals in the findings, Shroff notes. Nab-paclitaxel plus gemcitabine/cisplatin demonstrated increased efficacy in patients with gallbladder cancer and those with locally advanced disease; however, these signals were observed in small numbers of patients, and they warrant further investigation, Shroff says.

SWOG 1815 trial enrolled patients with newly diagnosed advanced biliary tract cancers. Patients were randomly assigned to receive gemcitabine and cisplatin with or without nab-paclitaxel. OS served as the trial’s primary end point, and secondary end points included PFS, ORR, disease control rate, and safety.

Previously reported data from a single-arm phase 2 trial (NCT02392637), which led to the inception of SWOG 1815, showed that nab-paclitaxel plus gemcitabine/cisplatin generated a median OS of 19.2 months and a median PFS of 11.8 months in 64 patients with advanced biliary tract cancers.