FDA gives Dynavax OK to resume hepatitis B trials

BOSTON (Reuters) - Dynavax Technologies Corp said on Thursday that U.S. regulators have given it the green light to move forward with its experimental hepatitis B vaccine.

The U.S. Food and Drug Administration placed the product on clinical hold 18 months ago due to safety concerns. Dynavax presented additional data to the agency, which has now given it the go-ahead to immunize patients with chronic kidney disease who do not respond well to an existing product.

The news will likely surprise investors, who had largely written off the vaccine, Heplisav. Last November the company’s shares fell to 15 cents each, down from more than $10.00 a share in late 2006. They closed on Wednesday at $1.75.

Hepatitis B is a chronic disease which can lead to cirrhosis of the liver. There is no cure for the condition. The only vaccine on the market is Engerix-B, made by GlaxoSmithKline Plc. Dynavax believes Heplisav is more effective and can be given in fewer doses than Engerix-B.

The FDA put Heplisav on hold last March after one patient developed a case of Wegener’s granulomatosis, an inflammatory autoimmune disease that affects the small blood vessels and can cause extensive tissue damage.

Heplisav combines a genetically engineered viral antigen with an adjuvant to create its vaccine. The adjuvant, designed to enhance the effectiveness of the antigen, targets Toll-like Receptor 9, a protein that tells the immune system to activate itself.

Dynavax, which is based in Berkeley, California, has completed a late stage trial of the vaccine, and said its next step is to enroll patients in a trial to compare vaccine made for commercial use with that made for use in clinical trials, to make sure they are the same.

Dino Dina, the company’s chief executive officer, said the company expects to complete the process by end of 2011. If all goes well, the vaccine could reach the market by the end of 2012 or early 2013.

Dynavax is also using its adjuvant in a different form to develop a universal influenza vaccine that can be used for seasonal and pandemic flu. The vaccine is in pre-clinical development.

Reporting by Toni Clarke, editing by Matthew Lewis