Purpose: This phase I trial assessed afatinib, an irreversible ErbB family blocker, plus vinorelbine in Japanese patients with advanced solid tumors not amenable to standard treatment.
Methods: Primary objectives were evaluation of safety and the maximum tolerated dose (MTD) of once-daily (QD) afatinib plus weekly intravenous vinorelbine. Secondary objectives included pharmacokinetic assessments and preliminary efficacy. Dose finding utilized a 3 + 3 design, with a starting dose of afatinib 20 mg QD plus vinorelbine 25 mg/m(2) weekly.
Results: Seventeen patients were enrolled. Dose level 2 (afatinib 40 mg and vinorelbine 25 mg/m(2)) exceeded the MTD; dose-limiting toxicities (DLTs) were considered vinorelbine-related. Dose finding continued with modified dose levels; dose level 2a: afatinib 40 mg and a reduced dose of vinorelbine 20 mg/m(2) and dose level 3: afatinib 40 mg and vinorelbine 25 mg/m(2) allowing omission of vinorelbine for grade ≥2 neutropenia/thrombocytopenia and afatinib dose modification for adverse events (AEs). At dose level 3, 1/6 patients had a DLT (upper abdominal pain requiring afatinib dose reduction). Overall, the most frequent treatment-related AEs (any/grade 3 and 4) were: neutropenia (100/71 %), leukopenia (100/59 %), diarrhea (94/0 %), anemia (71/12 %) and stomatitis (65/0 %). Two patients with breast cancer achieved a partial response; eight patients (various cancer indications) had stable disease. Pharmacokinetic analyses suggested no relevant drug-drug interactions.
Conclusions: Afatinib 40 mg QD plus vinorelbine 25 mg/m(2) weekly was tolerated in Japanese patients when dose modifications for known AEs for either compound were allowed. Tumor shrinkage was also observed. This dose schedule was recommended for phase II/III trials in Japanese patients.
Keywords: Afatinib; Dose escalation; Japanese; Phase I; Vinorelbine.