2107 POSTER Preliminary results of a phase I study of sunitinib plus paclitaxel for first-line treatment of advanced breast cancer

A Phase II Study Evaluating the Safety and Efficacy of Sunitinib Malate in Combination With Weekly Paclitaxel Followed by Doxorubicin and Daily Oral Cyclophosphamide Plus G-CSF as Neoadjuvant Chemotherapy for Locally Advanced or Inflammatory Breast Cancer

INTRODUCTION

Neoadjuvant chemotherapy is standard treatment for locally advanced breast cancer (LABC) or inflammatory breast cancer (IBC). We hypothesized that adding sunitinib, a tyrosine kinase inhibitor with antitumor and antiangiogenic activity, to an anthracycline and taxane regimen would improve pathologic complete response (pCR) rates to a prespecified endpoint of 45% in patients with HER2-negative LABC or IBC.

METHODS

We conducted a multicenter, phase II trial of neoadjuvant sunitinib with paclitaxel (S+T) followed by doxorubicin and cyclophosphamide plus G-CSF for patients with HER2-negative LABC or IBC. Patients received sunitinib 25 mg PO daily with paclitaxel 80 mg/m² IV weekly ×12 followed by doxorubicin 24 mg/m² IV weekly + cyclophosphamide 60 mg/m² PO daily with G-CSF support. Response was evaluated using pCR in the breast and the CPS + EG score (clinical-pathologic scoring + estrogen receptor [ER] and grade).

RESULTS

Seventy patients enrolled, and 66 were evaluable for efficacy. Eighteen patients (27%) had pCR in the breast (10 had ER⁺ disease and 8 had triple-negative disease). When defining response as pCR and/or CPS + EG score ≤2, 31 (47%) were responders. In pateints with ER positive disease, 23 (64%) were responders. The most common toxicities were cytopenias and fatigue.

CONCLUSIONS

Neoadjuvant S+T followed by AC+G-CSF was safe and tolerable in LABC and IBC. The study did not meet the prespecified endpoint for pCR; however, 47% were responders using pCR and/or CPS + EG score ≤2. ER positive patients had the highest response rate (64%). The addition of sunitinib to neoadjuvant chemotherapy may provide promising incremental benefit for patients with ER positive LABC.

Sunitinib as salvage treatment including potent anti-tumor activity in carcinomatous ulcers for patients with multidrug-resistant metastatic breast cancer

OBJECTIVE

To evaluate the efficacy and safety of single-agent sunitinib as salvage treatment in Chinese patients with multidrug-resistant metastatic breast cancer (MBC).

RESULTS

37 patients were enrolled with median age of 48 years. 17 had hormone receptor (HR)-positive tumors, 7 had HER2-positive tumors, and 10 had triple-negative tumors. Among 32 evaluable patients with follow-up, 6 (18.8%) achieved partial response, 14 (43.8%) achieved stable disease, and 11 (34.4%) exhibited tumor shrinkage. The response rate in 9 patients with carcinomatous ulcers was 77.8%. The median progression free survival (PFS) was 8.6 weeks. Patients with a better response had improved overall survival and PFS relative to patients with a worse response (p = 0.007, p < 0.001). Compared with HR-negative tumor, HR-positive tumor had significantly better response to sunitinib (p = 0.035). The most frequent non-hematologic adverse events were fatigue (82.8%) and hypertension (34.5%). Grade 3/4 hematologic toxicity included neutropenia (82.8%) and thrombocytopenia (79.3%). There was no correlation between the clinical response and IHC findings.

MATERIALS AND METHODS

Patients with MBC who were resistant to multiple salvage regimens (≥ 3 previous chemotherapy lines) were enrolled to receive sunitinib monotherapy. Dosage adjustment was allowed depending on adverse events. 14 patients underwent immunohistochemistry (IHC) testing for VEGF, PDGFR, EGFR and c-KIT.

CONCLUSIONS

Sunitinib salvage treatment provided modest antitumor effect to patients with refractory multidrug-resistant MBC, especially to those with troublesome carcinomatous ulcers. The treatment-related adverse events of sunitinib were manageable through dosage adjustment.

Antiangiogenic strategies in breast cancer management

Angiogenesis is considered one of the key mechanisms of tumour growth and survival. Therefore it represents an ideal pharmaceutical target. Many antiangiogenic agents have been developed so far in several solid tumours and also in breast cancer. Vascular endothelial growth factor (VEFG) is the main target and both monoclonal antibodies and small molecules belonging to the tyrosine kinase inhibitors directed against VEGF(R) have been developed. Some other therapeutic approaches have shown to exert some antiangiogenic activity, such as hormonal agents, metronomic chemotherapy, bisphosphonates and others. In this paper we provide an introduction of the current data supporting the angiogenesis in breast cancer and a review of the most relevant antiagiogenic therapies which have been investigated so far.