P2.06-011 Phase 2 Study of MM-121 plus Chemotherapy vs. Chemotherapy Alone in Heregulin-Positive, Locally Advanced or Metastatic NSCLC

The role of the HER3 receptor and its ligand heregulin (HRG) in the progression of multiple cancers has been well established. Seribantumab (MM-121) is a fully human, monoclonal IgG2 antibody that binds to the HRG domain of HER3, blocking HER3 activity. The correlation between the level of HRG mRNA in tumor tissue and progression free survival (PFS) were retrospectively analyzed in three completed randomized Phase 2 studies of seribantumab plus standard of care (SOC) versus SOC alone (NSCLC, breast cancer and ovarian cancer). In each of these studies, high levels of HRG mRNA predicted shortened PFS for patients who received SOC treatment, while the addition of seribantumab to SOC improved PFS for patients with HRG-positive (HRG+) tumors. This is consistent with the hypothesis that HRG expression defines a drug tolerant cancer cell phenotype shielded from the effects of cytotoxic or targeted therapies and that blockade of HRG-induced HER3 signaling by seribantumab counters the effects of HRG on cancer cells, with the potential to improve outcomes for HRG+ patients. It is estimated that up to approximately 50% of cases of all solid tumor indications are HRG+. This HRG expression may contribute to rapid clinical progression in a subset of patients with poor prognosis. In the ongoing randomized, open-label, international, Phase 2 study, NSCLC patients with HRG+ tumors are being prospectively selected using a HRG RNA in situ hybridization assay performed on a recent tumor tissue sample collected via fine needle aspiration, core needle biopsy or excision. Approximately 560 patients will be screened to support enrollment of 280 HRG+ patients, who will be randomized in a 2:1 ratio to receive seribantumab plus investigator’s choice of docetaxel or pemetrexed, or docetaxel or pemetrexed alone. Patients will be wild-type for EGFR and ALK and will have progressed following one to three systemic therapies, one of which must be an anti-PD-1 or anti-PD-L1 therapy, for locally advanced and/or metastatic disease. Overall survival (OS) is the primary endpoint of the study and secondary endpoints include PFS, objective response rate and time to progression. Safety and health-related quality of life will also be assessed. An interim analysis is planned when 50% of final OS events have been reported. Enrollment has been initiated with approximately 80 sites expected to participate worldwide. Clinical Trials Registry number: NCT02387216 Section not applicable. Section not applicable.