Antivirus Wrap-Up: Vaccines and More Fight Avian Influenza, Rotavirus

While the most recent FDA-approved vaccine is Merck’s RotaTeq oral therapeutic against rotavirus gastroenteritis in infants (see below), vaccines to combat seasonal influenza and a possible pandemic caused by the H5N1 virus have dominated the spotlight. Such developments come as federal and state government officials face increasing demands to prepare for a possible avian flu pandemic and boost spending (D. McNeil Jr., “States and Cities Lag in Bird Flu Readiness,” The NY Times, Feb. 6 and M. Fox, “Congress Urged to Spend More Money on Flu,” Reuters/USA Today, Jan. 31). So far Congress has provided only $3.3 billion out of the $7.1 billion requested by President Bush.

On Feb. 6, Sanofi Pasteur, the vaccine business of the Sanofi-Aventis Group (Swiftwater, PA, en.sanofi-aventis.com) shipped to the National Institutes of Health 15,000 doses of its investigational doses of vaccine to protect against H5N1 influenza strain. The doses will be used in NIH clinical studies to determine the optimal formulation of the vaccine. Sanofi’s formulation is prepared with various levels of antigen as well as an adjuvant, aluminum hydroxide. The company also completed production of additional bulk-concentrate of the H5N1 vaccine antigen, valued at $50 million, for the US government stockpile and in support of the US Department of Defense requirements.

Meanwhile, researchers continue to seek faster and more effective processes for developing vaccines against H5N1. Purdue University researchers, partnering with the Centers for Disease Control and Prevention (CDC, Atlanta, GA, www.cdc.gov), published promising results of an adenoviral-vector-based pandemic influenza vaccine study conducted in mice (The Lancet, Feb. 2). The egg-independent formulation does not involve an adjuvant and induced both humoral and cell-mediated immune responses against avian H5N1 influenza viruses.

FDA last week approved a CDC’s laboratory test to diagnose H5 strains of influenza in patients suspected to be infected with the virus. The test provides preliminary results on suspected H5 influenza samples within four hours once a sample arrives at the lab and testing begins.

ProImmune (Oxford, UK, www.proImmune.com) also announced it has developed a screening technology to help identify specific antigens on viruses such as H5N1 and enable rapid analysis of proteins derived from a pathogen for potential immunogencity. The company plans to begin a pilot study.

Sales for MedImmune’s FluMist reportedly dropped 56% last year compared with sales in 2004. As observed in a Feb. 3 Washington Post article, the vaccine’s poor performance may be the result of its requirement to remain frozen and the fact that it is approved only for healthy people from 5 to 49 years of age. The company is currently testing a new formulation that requires refrigeration in hopes of meeting approval for the 2007-2008 influenza season.

Also eyeing the 2007-2008 flu season is Australia’s major biopharmaceutical company, CSL Ltd. (Melbourne, www.csl.com.au). The company plans to initiate a human clinical study of its vaccine this year and announced plans to submit a biologics license application to FDA within 12 months. Contingent on FDA approval, CSL hopes to supply 20 million doses of its vaccine in the United States. The company also plans to double its existing vaccine manufacturing capacity to 40 million doses annually following an $80 million investment.

BD Medical (Franklin Lakes, NJ, www.bd.com), the medical technolog segment of BD, and GlaxoSmithKline (London, UK, www.gsk.com) have partnered to launch the industry’s first prefilled-syringe flu vaccines using BD’s Hypak platform and design. GSK previously announced plans to acquire Fluviral maker ID Biomedical Corp. in hopes of having the vaccine approved for the 2007 flu season. GSK announced plans to increase production of its “Relenza” seasonal flu vaccine as well as invest in a vaccine against the H5N1 strain, with clinical trials possibly this year.

On Feb. 17, FDA’s Vaccines and Related Biological Products Advisory Committee plans to discuss influenza strains to be included in the vaccine for the 2006-2007 season.

FDA Approves Vaccine to Prevent Rotavirus Gastroenteritis

The FDA has approved “RotaTeq,” an oral liquid vaccine developed by Merck & Co. (White House Station, NJ, www.merck.com) to prevent rotavirus gastroenteritis in infants.

RotaTeq is the only vaccine approved in the United States that can help protect against rotavirus, which, according to the CDC, is the most common cause of severe diarrhea among children, resulting in the hospitalization of nearly 55,000 children each year in the United States and the death of more than 600,000 children annually worldwide.

A different vaccine against rotavirus previously approved in 1998 was withdrawn because of its association with an increased risk of intussusception, a rare, life-threatening blockage or twisting of the intestine.

Although a safety study involving 70,000 children did not associate Merck’s RotaTeq with an increased risk of intussusception, the company plans to conduct additional post-licensure safety studies. CDC also will conduct a large study through its Vaccine Safety Datalink Program to detect any association of intussusception with RotaTeq.