Merck KGaA's efforts to expand its oncology brand Erbitux into new indications have hit a setback after the drug failed a phase III trial in advanced gastric cancer.
The EXPAND study compared Erbitux (cetuximab) given in combination with cisplatin and capecitabine as a first-line treatment for patients with advanced gastric adenocarcinoma, including adenocarcinoma of the gastro-esophageal junction (GEJ), to cisplatin and capecitabine given alone.
Sadly - and despite encouraging results in phase II trials – the Erbitux-based regimen failed to show an improvement in progression-free survival in these patients, which was the primary endpoint of the study.
Patients with these types of gastric cancer have a poor prognosis and are normally treated with palliative therapy only, so the failure of EXPAND is a hefty blow.
"As a company we will continue to invest in oncology research and development to find new treatments for these diseases with high unmet medical need," commented Dr Annalisa Jenkins, the head of global drug development and medical at the company's Merck Serono unit.
Erbitux has been a big earner for Merck in its current indications of metastatic colorectal cancer and head and neck cancer.
Its growth trajectory has however started to slow of late, particularly as a rival drug with a similar mechanism of action - Amgen/Takeda's Vectibix (panitumumab) - has gained approvals for first- and second-line treatment of metastatic colorectal cancer in Europe.
Erbitux's first-quarter sales came in at around €214m, up marginally year-on-year, and as the drug is Merck's second-biggest pharma product after multiple sclerosis drug Rebif (interferon beta) the company has been trying to re-inject momentum to the franchise with new indications.
In May, however, a phase III trial of the drug as an adjuvant treatment after surgery for stage III colon cancer ended in disappointment when Erbitux proved no more effective than currently-used chemotherapy.
Meanwhile, in 2009 an attempt to win approval in non-small cell lung cancer was rejected by the regulatory authorities in Europe, where Merck holds marketing rights for the drug, although the company re-filed with a narrower NSCLC indication last year.
The NSCLC indication was dropped in the US by the drug's originator, Eli Lilly subsidiary ImClone Systems, and US marketing partner Bristol-Myers Squibb after it was rejected by the FDA earlier this year.