ESMO 2014: Afatinib improves progression-free survival in recurrent, metastatic HNC

The tyrosine kinase inhibitor afatinib significantly improved progression-free survival in patients with recurrent or metastatic squamous cell carcinoma of the head and neck after failure of platinum-based chemotherapy, compared with methotrexate, researchers reported at the 2014 European Society for Medical Oncology (ESMO) congress, held September 26-30 in Madrid.

Patients who received treatment with 40 mg/day oral afatinib had a 20% reduction in risk of progression or death compared with patients who received methotrexate, with a median progression-free survival of 2.6 months in the Lux-Head & Neck 1 trial.

"The improvement in progression-free survival was associated with a significant delayed worsening of symptoms (such as pain, swallowing, and global health status) versus chemotherapy. Patients treated with afatinib had less pain over time than patients treated with methotrexate," stated study author Jean-Pascal Machiels, MD, a medical oncologist at Institut Roi Albert II at Cliniques Universitaires St. Luc in Brussels, Belgium, in a news release. "These are important outcomes for patients with these conditions."

Recurrent or metastatic squamous cell carcinoma of the head and neck often has a poor outcome, Dr. Machiels noted. "This is a poor prognosis population and a disease that does not get enough attention from the scientific community, because this group of patients often has severe comorbidities and social problems such as alcoholism and tobacco use."

These patients often have a relapse in the head and neck area, Dr. Machiels added.

"The location is responsible for many symptoms that are difficult to palliate: pain, breath disorder, and swallowing problems," he said.

Around 90% of squamous cell carcinomas of the head and neck overexpress epidermal growth factor receptor (EGFR). Afatinib works by irreversibly blocking the ErbB family of cell surface receptors, which include EGFR, human epidermal growth factor receptor 2 (HER2), HER3, and HER4.

In this phase III trial, researchers tried to see if inhibiting multiple ErbB receptors simultaneously would improve the clinical efficacy of EGFR-targeted therapy. They analyzed 483 patients with recurrent or metastatic head and neck squamous cell carcinoma whose cancer had progressed despite treatment with platinum-based therapy. Overall, 322 patients received 40 mg/day oral afatinib; 161 were given 40 mg/m²/week intravenous methotrexate.

The study met its primary end point, and afatinib significantly improved progression-free survival versus methotrexate, Dr. Machiels said.

"Afatinib improved progression-free survival and delayed worsening of symptoms, and it is the first tyrosine kinase inhibitor to demonstrate a significant benefit in this disease," he said.

The most frequent grade 3/4 drug-related adverse events were rash/acne (9.7% of patients) and diarrhea (9.4%). Fewer treatment-related dose reductions, discontinuations, and fatal events were seen with afatinib.

"We are pleased with the results because we showed a benefit, although modest, in a very well-designed controlled trial," Dr. Machiels said. "The difference of this trial compared to the others performed in the same setting is that it was a homogenous population. It sets a kind of baseline design that could be used to design further trials."

The trial did not demonstrate that afatinib improves survival.

"Many potential reasons could explain why we were not able to demonstrate a survival benefit," Dr. Machiels said. "It could be simply because afatinib does not improve survival. However, 50% of the patients in both arms received subsequent therapies that could have influenced the survival benefit, for example a significant number of patients received subsequent anti-EGFR therapies in the methotrexate arm."

Future studies should focus on understanding which patient groups derive a clinically meaningful benefit from afatinib, the researchers said. They hope to provide further molecular insights and hypotheses to identify patients who benefit.

"We should hope that based on the new molecular data that is becoming available and through advances in the understanding of the molecular biology of this disease, some new treatments will be investigated in a near future," Dr. Machiels said.