Conditions: Metastatic Breast Cancer
Keywords: HER2 positive breast cancer first line treatment Dasatinib SRC kinase Trastuzumab resistance
Allocation: NA | Intervention model: SINGLE_GROUP
Enrollment: 37
Healthy volunteers: no

Brief summary:
This is a single-arm, open-label, phase I/II study. In the phase I, patients with Human Epidermal Growth Factor Receptor 2 (HER2) positive MBC will be treated with paclitaxel, trastuzumab and increasing doses of dasatinib to determine the Maximum Tolerated Dose (MTD), Dose Limiting Toxicity (DLT) and Recommended Phase II Dose (RPD) of the combination. Once the RPD has been identified, 48 patients will be treated at that dose to evaluate the efficacy and safety of the combination in the phase II.

Detailed description:
Eligible patients will be enrolled and treated with 4-week cycles of trastuzumab 2 mg/kg IV weekly (following a loading dose of 4 mg/kg in cycle 1) and paclitaxel 80 mg/m2 weekly x 3 weeks followed by a rest period of 7 days. Dasatinib will be administered orally in two dose levels 100 and 140 mg once daily (a -1 dose level is included just in case dose de-escalation is needed). Treatment will be repeated on Day 1 of a 28-day cycle in all patients (both in the phase I as in the phase II) until radiographic or symptomatic progression or unacceptable toxicity occurs. Only in the phase I and in all patients included in every different dose level, the first cycle will last 38 days.

Primary Objective:

* To determine the maximum tolerated dose (MTD) and recommended phase II dose (RPD) of dasatinib in combination with fixed doses of trastuzumab and paclitaxel in HER2-positive MBC patients (Phase I).
* To determine the efficacy, measured by objective response rate (ORR) in HER2-positive MBC patients with measurable disease (Phase II).

Secondary Objective(s):

* To characterize the safety of the combination (in both phase I and phase II).
* To evaluate the Clinical Benefit Rate (CBR), Time to Progression (TTP), Progression Free Survival (PFS) and Response Duration (RD) (in the phase II).
* To evaluate the pharmacokinetics (PK) of the combination (in the phase I and selected patients in the phase II if necessary).
* To evaluate molecular characteristics that may be predictive of the activity (or lack of) and any correlation between the biological activity of the study treatment and the disease outcome.

Exploratory objective:

• To explore the correlation between the lymphocytosis and efficacy.

Sample Size:

Phase I: following the 3+3 rule, a minimum of 6 and a maximum of 12 patients will be recruited.

Phase II:Assuming 10% drop-out rate, 48 patients are required to enter the study.

The duration of the study, from first patient visit to last patient visit will be approximately 42 months.

Arms:
arm 1: Eligible patients will be enrolled and treated with 4-week cycles of trastuzumab 2 mg/kg IV weekly (following a loading dose of 4 mg/kg in cycle 1) and paclitaxel 80 mg/m2 weekly x 3 weeks followed by a rest period of 7 days. Dasatinib will be administered orally in two dose levels 100 and 140 mg once daily (QD) (a -1 dose level is included just in case dose de-escalation is needed). Treatment will be repeated on Day 1 of a 28-day cycle until radiographic or symptomatic progression or unacceptable toxicity occurs. Only in the phase I, the first cycle will last 38 days.

Interventions: intervention 1: Dasatinib intervention 2: Trastuzumab intervention 3: Paclitaxel
Intervention descriptions: intervention 1: None intervention 2: None intervention 3: None

Protocol document: