A phase I study of 5-azacytidine and erlotinib in advanced solid tumor malignancies

The epidermal growth factor receptor (EGFR) is a validated target in malignancy; however, patients with wild type EGFR obtain little sustained benefit from anti-EGFR monotherapy. Epigenetic therapy to reactivate tumor suppressor genes may enhance the anti-proliferative effect of erlotinib. This phase I study evaluated the combination of erlotinib and 5-azacytidine for safety and maximal tolerated dose (MTD).

Thirty patients with advanced solid tumors were treated in a standard 3 + 3 cohort design. Erlotinib was dosed at 150 mg daily, and 5-azacytidine was escalated by increasing the number of daily doses of 75 mg/m(2) per cycle. Patients were followed for dose-limiting toxicity (DLT). Efficacy was assessed by RECIST criteria.

Common non-hematologic toxicities included rash, diarrhea, nausea, and fatigue; the majority was ≤ Grade 2. DLTs included conjunctivitis in cohort 1 and infusion reaction in cohort 2. No DLTs occurred in cohorts 3, 4, or 5; however, 2 serious neutropenic infections arose in cohort 5 after cycle 1. Cohort 4 was expanded to 6 patients and was the MTD. Partial response (lung, ovarian) and stable disease occurred in 2 and 11 patients, respectively. Median progression-free survival was 2 months. Two patients with lung and larynx cancer had prolonged stable disease.

The combination of erlotinib and 5-azacytidine was well tolerated with interesting clinical activity in lung, head and neck, and ovarian cancer. The recommended dose for phase II study is erlotinib 150 mg daily and 5-azacytidine 75 mg/m(2) daily on days 1-4 and 15-18 of a 28-day cycle.