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* Patients with certain treatment history could benefit
* Drug tecemotide formerly known as Stimuvax
* Vaccine had failed in previous trial (Adds survival data, background on cancer vaccines)
By Ludwig Burger
FRANKFURT, Sept 25 (Reuters) - German drugmaker Merck KGaA will conduct new tests on an experimental lung cancervaccine which failed a previous late-stage clinical trial, itsaid on Wednesday.
Merck said it would test the drug formerly known as Stimuvaxand now called tecemotide on patients that had been givenchemotherapy and radiotherapy simultaneously in an initial roundof treatment.
The previous trial, which also included patients that hadbeen given chemotherapy and radiotherapy separately, failed toprovide evidence of improved survival.
The drug - licensed from U.S. biotech firm Oncothyreon - will be tested on patients with locally advancedStage III non-small cell lung cancer (NSCLC), which cannot besurgically removed, unchanged from the previous trial calledSTART, the firm said.
"The START data delivered important insights that we believejustify further investigation in a new Phase III programme,"said Annalisa Jenkins, Merck's head of drug development.
Developing cancer vaccines that prime the immune system toattack tumour cells, is a high-risk, high-reward field ofmedicine that has seen a string of setbacks.
An experimental cancer vaccine from GlaxoSmithKline failed to help melanoma patients in a closely watched clinicaltrial. Dendreon Corp's Provenge, a pioneer cancervaccine, has failed to meet sales expectations.
Merck said detailed analysis of the previous trial showedthat patients with a treatment history of simultaneouschemotherapy and radiotherapy had an overall survival of 30.8months after taking tecemotide, versus 20.6 months in a controlgroup of patients treated with placebo.
Investors took a cautious stance, with shares in Mercktrading 0.2 percent lower at the open.
The German company said about 1,000 patients would take partin the new study, called START2, compared with 1,200participants in the predecessor START trial.
The company did not say by how much it was reducing itstarget market by focusing on a smaller subset of patients, butit described simultaneous chemotherapy and radiotherapy as thecurrent standard of care. (Reporting by Ludwig Burger; Editing by Mark Potter)
