Merrimack Pharmaceuticals has enrolled the last patient in the second cohort of a two-cohort randomized Phase II clinical trial of MM-121 (SAR256212) in combination with paclitaxel in the neoadjuvant setting of HER2-negative breast cancer.
MM-121, a fully human monoclonal antibody that targets ErbB3, a cell surface receptor implicated in tumour growth and survival, is currently being developed in partnership with Sanofi.
The Phase II clinical trial is aimed at assessing whether the combination of MM-121 with paclitaxel is more effective compared with treatment using paclitaxel alone when administered as part of a neoadjuvant treatment regimen in two patient groups of HER2-negative, locally advanced breast cancer patients.
Around 100 patients with triple negative breast cancer (TNBC) were enrolled in the second group and the final results are expected in 2014.
TNBC is diagnosed when a patient's tumour has tested negative for HER2, estrogen receptor (ER) and progesterone receptor (PR) biomarkers.
The first group under the Phase II study was fully enrolled in April and comprised 100 patients with tumours that are HER2-negative, but either ER and PR biomarkers are positive and the results from this group are expected in fall 2013.
Merrimack Pharmaceuticals vice-president and MM-121 Project Leader William Kubasek said: "With pretreatment biopsies required in three of these studies, we believe that our translational clinical research programme will provide the foundation to better understand the biomarkers associated with ErbB3 signaling, setting the stage for the next phase of development of MM-121."
The company said that after treatment with either MM-121 and paclitaxel, or paclitaxel alone, patients from both groups will receive standard treatment with doxorubicin and cyclophosphamide and be monitored until surgical resection.
In 2009, Merrimack and Sanofi had entered into an exclusive, global license and collaboration agreement for MM-121.