US-based Merrimack Pharmaceuticals has started a Phase II clinical trial of its fully human monoclonal antibody, MM-121, in combination with docetaxel or pemetrexed versus docetaxel or pemetrexed alone to treat patients with heregulin positive, locally advanced or metastatic non-small cell lung cancer (NSCLC).
A total of 120 heregulin positive patients will be enrolled in this global, open-label, biomarker-selected, randomised trial and they will be randomised 2:1 to receive either MM-121 plus the investigator's choice of docetaxel or pemetrexed, or the investigator's choice of docetaxel or pemetrexed alone.
In order to take part in the trial, patients must have failed prior treatment with no more than two lines of therapy for locally advanced or metastatic disease.
The trial's primary endpoint is progression free survival (PFS), while secondary endpoints include overall survival, objective response rate, safety and tolerability.
The company's antibody MM-121 targets ErbB3, a cell surface receptor that is activated by the ligand heregulin. MM-121, when used in the combination setting, is designed to block ErbB3 signalling in order to improve the anti-tumour effect of a combination therapy partner.
Heregulin-driven ErbB3 signalling has been implicated as a mechanism of tumour growth and resistance to targeted, cytotoxic and anti-endocrine therapies.
Merrimack MM-121 global development lead Akos Czibere said: "This marks the first MM-121 trial we've initiated where only patients with a high heregulin biomarker profile will be enrolled into the study.
"It builds on our learnings from the previous MM-121 Phase II clinical trials we completed across lung, ovarian and breast cancers where we saw a clear trend of patients in those studies with this biomarker profile benefiting from combining MM-121 with standard therapies.
"This study is a significant step toward preparing a registration trial of MM-121 in non-small cell lung cancer, and further supports Merrimack's systems biology approach and its impact on drug discovery and development."
The company is pursuing this trial based on positive results from a broad MM-121 Phase II programme, which identified high heregulin levels as a potential prognostic factor of poor response to standard-of-care therapy across multiple cancers.
Results from this Phase II programme also showed that patients with heregulin-high tumours experienced a longer time to progression when they received a combination of MM-121 with their standard-of-care therapy as compared to patients who received the standard therapy alone.
The company said that across the three different standard-of-care combination regimens, a consistent safety profile showed a modest yet tolerable increase in adverse events.
Image: Micrograph of a squamous carcinoma, a type of non-small-cell lung carcinoma. Photo: courtesy of Nephron.