Phase II study of Pseudomonas aeruginosa-Mannose-Sensitive hemagglutinin in combination with capecitabine for Her-2-negative metastatic breast cancer pretreated with anthracycline and taxane

Abstract

Purpose: Metastatic breast cancer (MBC) remains an incurable disease despite major therapeutic advances. Pseudomonas aeruginosa-mannose-sensitive hemagglutinin (PA-MSHA) has been established to have anti-proliferative effects against breast cancer cells in preclinical experiments, and is indicated for treatment of cancer in China. We performed a phase II trial combining PA-MSHA with capecitabine in patients with heavily pretreated MBC.

Methods: Eligibility criteria included human epidermal growth factor receptor 2-negative MBC, prior therapy with anthracyclines and taxanes, at least one prior chemotherapy regimen for metastatic disease or early relapse after a taxane plus anthracycline adjuvant regimen, and adequate organ function and performance status. PA-MSHA 1 mg was administered subcutaneously every other day and capecitabine 1000 mg/m2 orally twice a day for 2 weeks on, 1 week off. The primary end point was progression-free survival.

Results: A total of 97 patients were enrolled. Median progression-free survival (PFS) was 4.0 months [95 % confidence interval (CI) 3.0-4.9], which was not significantly different from that in historical controls. However, median PFS was significantly longer (8.2 months; 95 % CI 6.7-9.7) in 24 patients with moderate immune-related adverse events (irAEs) such as fever or skin induration at the injection site than in those with no or mild irAEs (3.1 months, 95 % CI 2.5-3.6; p = 0.003). Overall survival was also improved in these patients (25.4 vs. 16.4 months; p = 0.044). PA-MSHA has a good safety profile, with only 6 patients (6.2 %) discontinuing treatment. PA-MSHA did not increase capecitabine-related toxicities such as hand-foot syndrome, nausea, and vomiting.

Conclusion: Adding PA-MSHA to capecitabine has a good safety profile in patients with heavily pre-treated MBC, although benefit from this regimen might occur only in patients with moderate PA-MSHA-related adverse events.

Trial registration: ClinicalTrials.gov NCT01380808.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1. Consort flow chart of this trial.

Fig 2. PFS curve of patients with different grades of irAEs.

Patients with grade 2 or higher irAEs (N = 24, events 20) had longer PFS than those who had no or grade 1 irAEs (N = 69, events 63) (p = 0.003).

Fig 3. OS curve of patients with different grades of irAEs.

Patients with grade 2 or higher irAEs (N = 24, events 7) had longer OS than those who had no or grade 1 irAEs (N = 69, events 31) (p = 0.044).