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Keywords:

  • afatinib;
  • epidermal growth factor receptor;
  • EGFR;
  • EGFR-activating mutations;
  • ErbB Family Blocker;
  • gene amplification;
  • human epidermal growth factor receptor 2;
  • HER2;
  • solid tumors

BACKGROUND

The efficacy of afatinib, an irreversible ErbB Family Blocker, was evaluated in patients who had 1 of 4 categories of solid tumors with epidermal growth factor receptor/human epidermal growth factor receptor 2 (EGFR/HER2) gene amplification or EGFR-activating mutations.

METHODS

Patients with previously treated but ErbB inhibitor-naive esophagogastric, biliary tract, urothelial tract, or gynecologic cancers (lung cancers were excluded) harboring EGFR/HER2 gene amplification or high polysomy were identified by fluorescence in situ hybridization (FISH). Tumors were also screened for EGFR mutations. The primary endpoint was the objective response rate; secondary endpoints included the clinical benefit rate, pharmacokinetics, and safety.

RESULTS

Of 385 prescreened patients, 38 had FISH-positive tumors (10 with EGFR amplification and 29 with HER2 amplification or high polysomy [1 tumor had EGFR/HER2 high polysomy]; none had EGFR-activating mutations), and 20 patients received treatment with afatinib 50 mg daily. The objective response rate was 5% (1 of 20 patients), and the best objective response included 1 complete response. Eight patients experienced stable disease. The most frequently reported adverse events were diarrhea, rash, and decreased appetite. The trial closed early because of slow recruitment.

CONCLUSIONS

Single-agent afatinib activity was limited, yet encouraging, in selected tumors that were screened prospectively for target activation. The implementation of a biomarker-driven approach using a low-frequency biomarker for patient selection across multiple tumor types can be challenging. Cancer 2013;119:3043—3051. © 2013 American Cancer Society.