Germany’s Merck KGaA lost a key product in its late-stage development pipeline today, after deciding there was no longer any point pressing on with development of sarizotan as a treatment for Parkinson’s disease.

Merck made the decision after taking a look at the results of two Phase III studies of sarizotan in advanced Parkinson’s disease patients suffering from dyskinesia.

The Phase III studies did not confirm earlier Phase II findings or the results from preclinical studies, said Merck in a statement. “Merck does not plan to

pursue further development of this compound,” it said. The company had earlier said it hoped to file for approval of the drug in both Europe and the USA later this year.

The decision leaves a hole in Merck’s near-term pipeline as sarizotan was one of just two new drugs in later-stage testing at the company, the other being cancer vaccine Stimuvax, which it acquired from Biomira earlier this year. The latter product is just starting a Phase III programme.

The failure also adds to the disappointment Merck suffered after failing to complete a takeover of fellow German drugmaker Schering AG, which now look set to complete a favoured merger with Bayer. Merck had hoped to join forces with Schering to boost its specialty pharmaceutical portfolio and become more competitive in the global pharma industry.

News of sarizotan’s demise had sparked a 5% fall-off in Merck’s shares to 70.28 euros in early morning trading today.

Merck will now rely more heavily on its cancer drug Erbitux (cetuximab) for sales growth in its pharmaceuticals division

The two trials, PADDY 1 and PADDY 2, tested twice-daily dosing of sarizotan 1mg tablets to see if the drug could achieve a 25% improvement in dyskinesia symptoms, but failed to meet this efficacy threshold. Sarizotan is a combined serotonin 5-HT1a agonist, with additional activity at the dopamine D3 and D4 receptors.