Zurich - Cytos Biotechnology said Tuesday a vaccine it was developing for hypertension has failed to show positive results and the company would scale back a significant amount of its workforce in response.

The company's stock was down over 33 per cent in mid-afternoon trading on the Zurich exchange following the announcement.

"The study results show that the vaccine was safe and well tolerated, but the new treatment regimen failed to induce a significant reduction of the ambulatory blood pressure," Cytos said in a statement.

Tests during an earlier phase of trials of the vaccine known as CYT006-AngQb had shown more promising outcomes, the company said.

"In order to align its financial resources on the key development programs and its collaborations with Novartis and Pfizer, the company plans to reduce its workforce of presently 135 full time employees by up to 57," the statement said.

This would cut the company's gross cash burn rate to 36 million Swiss francs (30.4 million dollars) this year and in 2010 to approximately 25 million francs, the company said, allowing it to invest in research and development.

Cytos develops so-called immunodrugs meant to treat and prevent common chronic diseases. (dpa)