Our lung cancer program is focused on advancing two combination approaches shown in preclinical studies to inhibit lung cancer cell growth. The first approach combines entinostat with erlotinib, an approved epidermal growth factor receptor inhibitor, and the second approach combines entinostat with azacitidine, a DNA methyltransferase inhibitor. We believe that successful treatment of NSCLC and introduction of novel therapeutic approaches will be dependent on the identification of biomarkers that allow patient selection for the optimization of response.
We conducted a randomized, double-blind, placebo-controlled Phase 2b clinical trial, which we refer to as the ENCORE 401 clinical trial, of entinostat in combination with erlotinib compared to erlotinib plus placebo. The trial enrolled 132 patients with metastatic NSCLC who experienced disease progression after one or two prior regimens of therapy or within six months of completion of chemotherapy following surgery. Patients in the trial received treatment with erlotinib in a 150 mg dose daily with entinostat or placebo in a 10 mg dose on days 1 and 15 of a 28-day cycle. Patients could receive up to six cycles of therapy, subject to discontinuation in the event of disease progression or unacceptable toxicity. While the ENCORE 401 clinical trial did not meet its primary endpoint, we identified a subset of patients that had extended overall survival with entinostat combined with erlotinib versus erlotinib alone using a predefined, retrospective analysis. These patients expressed high levels of epithelial cadherin (E-cadherin) a biomarker of epithelial lung cancers in their tumor samples. As a follow up to the ENCORE 401 clinical trial and to confirm the E-cadherin patient biomarker enrichment strategy, we have planned a randomized, Phase 2 clinical trial of 200 NSCLC patients selected prior to randomization based on expression of high levels of the E-cadherin biomarker in their tumor.
In a second completed Phase 2 clinical trial, our collaborators at Johns Hopkins University under sponsorship of the NCI, conducted a single-arm, two-stage, open-label clinical trial of the combination of entinostat and azacitidine in patients with recurrent metastatic NSCLC. All of these patients had been heavily pre-treated with a median of three prior regimens for metastatic disease and had shown no meaningful response to such treatment. Although this population was heavily pretreated, patients given the combination of entinostat and azacitidine achieved objective responses, including a complete response, a partial response with complete resolution of multiple liver metastases, and several patients with durable stable disease.
Development Plan of Entinostat in Lung Cancer
The following trials of entinostat combinations planned by investigators at Johns Hopkins University are designed to build on the initial NCI-funded trial data in metastatic NSCLC to further validate the observation that dual epigenetic therapy can augment the clinical activity of cytotoxic or immune therapy in these patients.
- NCI-9253: Epigenetic Priming to Chemotherapy Trial. This NCI-funded Phase 2 clinical trial is currently enrolling up to 165 metastatic NSCLC patients in three different arms,(i) chemotherapy alone, (ii) chemotherapy preceded by injectable azacitidine plus entinostat, or (iii) chemotherapy preceded by oral azacitidine plus entinostat. The primary objective of the trial is to determine the percent of patients without disease progression at six months. We expect to see the proof-of-concept data for this trial in late 2015.
- J1353: Epigenetic Priming to Immunotherapy Trial. This investigator-sponsored Phase 2 clinical trial, funded by Stand Up To Cancer, is currently enrolling up to 120 patients with metastatic NSCLC and is designed to test the ability of epigenetic therapy—either oral azacitidine alone or the entinostat and azacitidine combination—to enhance the response of NSCLC patients to nivolumab, a type of immunotherapy. We expect to see the proof-of-concept data for this trial in late 2015.