Phase 2 study of combination SPI-1620 with docetaxel as second-line advanced biliary tract cancer treatment

This multicentre, open-label study evaluated the efficacy and safety of SPI-1620, an analogue of endothelin-1, administered in combination with docetaxel as second-line treatment for patients with advanced biliary tract cancer (ABTC).

Eligible patients received continuous cycles of combination therapy with SPI-1620 (11 μg m^-2) and docetaxel (75 mg m^-2) intravenously every 3 weeks until disease progression (PD) or intolerable toxicity. Tumour response was evaluated using computed tomography or magnetic resonance imaging every 2 cycles (6 weeks). The primary efficacy end point was progression-free survival (PFS); secondary end points included overall response rate (ORR), duration of response, and overall survival (OS) that were estimated using the Kaplan-Meier method.

Of the 30 enrolled patients, 25 patients had qualifying events (PD or death), 1 patient was nonevaluable, and 4 patients were censored at the time of their last tumour assessment. Our primary end point of PFS ⩾5 months was not reached. Median PFS was 2.6 months (95% confidence interval (CI): 1.4-2.8), ranging from 0.7 to 8.4 months. The ORR was 10.3% (95% CI: 0.02-0.27). Eleven additional patients achieved stable disease. The OS was 4.87 months. The most common grade 3-4 toxicities were febrile neutropenia and neutropenia.

The addition of docetaxel to SPI-1620 in second-line ABTC did not meet the pre-specified primary end point of PFS ⩾5 months in unselected patient population.