NCT07494448

Phase Ib/II Study of Zanidatamab Plus Tucatinib and Chemotherapy in HER2-Positive Advanced Breast Cancer

PHASE IB/II STUDY TO EVALUATE SAFETY AND PRELIMINARY EFFICACY OF ZANIDATAMAB IN COMBINATION WITH TUCATINIB AND CHEMOTHERAPY (CAPECITABINE OR ERIBULIN MESYLATE) IN HER2-POSITIVE ADVANCED BREAST CANCER

• Status: Not Yet Recruiting
• Phase: Phase 1 / Phase 2
• Study type: Interventional
• Enrollment: 24 (estimated)
• Sponsor: MedSIR · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The JAZMINE study is a multicenter, open-label, non-comparative, phase Ib/II clinical trial to evaluate safety and preliminary efficacy of zanidatamab in combination with tucatinib and chemotherapy (capecitabine or eribulin mesylate) in HER2-positive advanced breast cancer.

Detailed description

After signing the informed consent form (ICF) and confirmation of eligibility, adult participants (≥18 years) with HER2-positive advanced breast cancer (ABC) will be enrolled in this multicenter, open-label, phase Ib/II clinical trial. In phase Ib, participants will be assigned to one of two non-randomized cohorts and will receive zanidatamab in combination with tucatinib and either capecitabine or eribulin, following a Bayesian optimal interval (BOIN) dose-escalation design to determine the recommended phase II dose (RP2D) of capecitabine and eribulin, when administered with zanidatamab and tucatinib. Dose escalation will be conducted for each drug combination separately, meaning that if the phase Ib Study in one Cohort is stopped due to safety, it can continue in the other. In phase II, eligible participants will be randomized 2:1 to receive zanidatamab plus tucatinib and chemotherapy (capecitabine or eribulin at the RP2D) or a control regimen of trastuzumab, tucatinib, and capecitabine at standard doses. Treatment will continue until disease progression, unacceptable toxicity, withdrawal of consent, death, or study termination, whichever occurs first.

Conditions

• HER 2 Positive Advanced Breast Cancer
• Breast Cancer

Interventions

Type	Name	Description
DRUG	Zanidatamab	Will be administered as an intravenous (IV) infusion on Day 1 of each 21-day treatment cycle (Q3W). The dose of zanidatamab will be weight-based: 1800 mg for participants weighing \<70 kg and 2400 mg for participants weighing ≥70 kg. During phase Ib, the dose of zanidatamab will remain constant.
DRUG	Tucatinib	Will be administered orally at a dose of 300 mg twice daily (BID) on a continuous basis throughout each 21-day treatment cycle. During phase Ib, the dose of tucatinib will remain constant.
DRUG	Capecitabine	Will be administered orally twice daily (PO BID) on Days 1-14 of each 21-day treatment cycle during phase Ib. Dose escalation will be performed with a starting dose of 750 mg/m² PO BID, with escalation to 1000 mg/m² PO BID based on tolerability. If the 750 mg/m² dose is not well tolerated, capecitabine will be de-escalated to 650 mg/m² PO BID.
DRUG	Eribulin Mesilate injection	Will be administered intravenously on Days 1 and 8 of each 21-day treatment cycle during phase Ib. Dose escalation will be performed with a starting dose of 1.1 mg/m², with escalation to 1.4 mg/m² based on tolerability. If the 1.1 mg/m² dose is not well tolerated, eribulin will be de-escalated to 0.7 mg/m².

Timeline

• Start date: 2026-07-01
• Primary completion: 2027-12-31
• Completion: 2028-05-31
• First posted: 2026-03-27
• Last updated: 2026-03-27