A phase Ib, open-label study to assess the safety of continuous oral treatment with afatinib in combination with two chemotherapy regimens: cisplatin plus paclitaxel and cisplatin plus 5-fluorouracil, in patients with advanced solid tumors

In this phase Ib, dose-escalation study, the oral irreversible ErbB family blocker afatinib (BIBW 2992) was combined with cisplatin (Cadila Healthcare Ltd, Ahmedabad, India) 50 or 75 mg/m2/paclitaxel (Bristol-Myers Squibb Pharmaceuticals Ltd, New York, USA) (Taxol)175 mg/m2 (regimen A) or cisplatin 75–100 mg/m2/5-fluorouracil 750–1000 mg/m2 (regimen B) in patients with advanced solid tumors. The primary objective was to assess dose-limiting toxicities (DLTs) during cycle 1 for each regimen, from which the maximum tolerated dose (MTD) was determined. Patients received once daily oral afatinib 20, 30, 40 or 50 mg in 21-day cycles (3 + 3 design). The MTD for afatinib in regimens A (n = 26) and B (n = 21) was determined as 20 mg and 30 mg following DLTs in five and four patients in cycle 1, respectively. Most frequent adverse events (AEs, any grade) were diarrhea and nausea. Disease control was observed in 54% and 29% of patients in regimens A and B, respectively. Plasma sampling suggested no relevant pharmacokinetic interaction between afatinib and the chemotherapeutic agents. The MTD of afatinib was 20 mg with cisplatin–paclitaxel and 30 mg with cisplatin–5-fluorouracil. Pre-emptive management of side-effects is important to maintain adequate safety and tolerability. Both combinations showed antitumor activity across tumor types and lines of prior treatment.