The disappointment from the latest set of lung cancer data unveiled by Genentech from a study on Avastin has been compounded by a MorganStanley report which claims that the blockbuster could be facing some serious competition in that indication from ImClone’s Erbitux.

Genenetech provided an update on results from a Roche-sponsored Phase III study of Avastin (bevacizumab), called AVAiL, which confirmed that the drug in combination with chemotherapy (in this case gemcitabine) improved progression-free survival in patients with advanced non-small cell lung cancer (NSCLC) compared with chemotherapy alone. However it also revealed that Avastin did not prolong overall survival.

Genentech reiterated that Avastin was recently granted accelerated approval by the US Food and Drug Administration for NSCLC in combination with another chemotherapy, paclitaxel. However the data was overshadowed by a claim from Morgan Stanley that a second late-stage trial –BMS-099 – of a rival treatment, ImClone’s Erbitux (cetuximab), shows that the drug does prolong survival in lung cancer patients.

The claim was made by analyst Andrew Baum in a note to clients about Erbitux, which is sold in the USA by Bristol-Myers Squibb and in Europe by Merck KGaA, who cited an unidentified but “reliable public source”. This would mean that Erbitux has two Phase III trials with proven survival benefit compared with only one for Avastin.

The Morgan Stanley claim caused great excitement among analysts and Citigroup analyst Yaron Werber said in a note to investors that this is a positive for Erbitux “since it suggests that Avastin is not as effective as was originally thought and reinforces that not everyone can benefit” from the drug.

Last September Merck unveiled initial data from its FLEX study, using Erbitux in combination with platinum-based chemotherapy (vinorelbine plus cisplatin) met its primary endpoint of increasing overall survival compared with chemotherapy alone in patients with advanced (stages IIIb or IV) NSCLC. Detailed results are expected to be presented at the American Society of Clinical Oncology annual meeting at the end of May in Chicago.