Merck KGaA has withdrawn a filing in Europe to extend the use of its blockbuster Erbitux in patients with lung cancer after regulators required more information.

Specifically, the German drugmaker has taken "the strategic decision to voluntarily withdraw" the marketing authorisation application to the European Medicines Agency of a label extension for Erbitux (cetuximab). It hoped to get the green light for the drug to be used in combination with standard first-line platinum-based chemotherapy in patients with advanced or metastatic NSCLC with high epidermal growth factor receptor  expression.

Annalisa Jenkins, head of global drug development and medical for the Merck Serono division, said "we are disappointed that we have not been able to move forward with the filing in NSCLC but it has become apparent that further data will be required to support the clinical utility of Erbitux in this specific population". She added that “we continue to advance our oncology pipeline, for example also by planning to initiate a randomised Phase III trial of TH-302 in patients with advanced first-line pancreatic cancer together with our partner Threshold Pharmaceuticals".

Threshold-partnered drug overall survival data

However, yesterday, shares in Threshold took a tumble after the firm presented lacklustre Phase IIb data on TH-302.

In February, the US firm announced that the study met its primary endpoint demonstrating a statistically significant 63% improvement in progression free survival (PFS) for patients treated with TH-302 and Eli Lilly's Gemzar (gemcitabine) versus the latter alone. This represented a two-month increase in PFS.

Now, new findings on overall survival, which was a secondary endpoint of the study, indicate that patients treated with Gemzar alone had a median overall survival of 6.9 months compared with 9.2 months for patients on the highest dose of TH-302 plus gemcitabine, which was not statistically significant. Threshold said the trial was not designed to detect a statistically significant improvement in OS and included a cross-over component.

The Merck pact for TH-302, signed in February, could be worth up to $550 million to Threshold.