CONTRADICTING EVIDENCE: Patients with metastatic HER2+ breast cancer…The primary objective of the phase II was to assess the progression free survival (PFS) of the combination of ruxolitinib plus trastuzumab compared to historical control. Of 26 evaluable patients in phase II, the median PFS was 8.3 weeks (95% CI 7.1, 13.9). Among the 14 patients with measurable disease, 1 patient had a partial response and 4 patients had stable disease. the combination of ruxolitinib and trastuzumab did not lead to an improvement in PFS compared to historical control in patients with trastuzumab-resistant metastatic HER2+ breast cancer.

This is an investigator-initiated, multi-center, open-label, phase I/II trial of ruxolitinib plus trastuzumab in patients (pts) with HER2+ MBC...there was 6-month PFS of 21% in this heavily pre-treated HER2+ MBC population. Ongoing analyses will be done to determine factors that predict clinical benefit.