There was some good news for Merck & Co yesterday, after a US Food and Drug Administration advisory committee voted unanimously its Rotateq vaccine was safe and effective in the prevention of rotavirus gastroenteritis.

As expected, the panel asked Merck to monitor use of the product carefully after licensing to make sure that the product is safe, particularly with regard to the serious intestinal twisting side effect (intussusception) that led to the only previously approved rotavirus vaccine – Wyeth’s RotaShield – being withdrawn from the market in 1999.

But it agreed that the data indicated that RotaTeq was both safe and effective in preventing rotavirus gastroenteritis. Ahead of the meeting, documents published on the FDA website suggested that the agency was happy with the efficacy results from one study but had reservations about the data from a second.

The panel’s recommendation was based on data presented from Phase III clinical trials involving 70,000 infants, including the Rotavirus Efficacy and Safety Trial (REST), one of the largest vaccine clinical trials ever conducted.

Rotavirus gastroenteritis is the most common cause of severe dehydrating diarrhea in infants and young children, causing an estimated 250,000 emergency department visits and 500,000 visits to physicians offices each year in the USA. Merck has also filed for approval of Rotateq in more than 50 other countries worldwide, and started a major clinical development programme for the vaccine in Asia earlier this month.

Merck and European partner for Rotateq, Sanofi Pasteur MSD, are going head-to-head with GlaxoSmithKline in the race to bring rotavirus vaccination back to world markets. GSK's Rotarix product candidate has already been launched in Mexico, its first market, but has not yet been filed for approval in the USA.

Meanwhile, another Merck vaccine - Zostavax for the prevention of shingles in people aged over 50 - will go up against the advisory panel later today. In data submitted to the FDA, Zostavax reduced the incidence of shingles by 51% compared to placebo and reduced the symptom burden among patients in whom the disease - a painful resurgence of chickenpox virus - did occur.

Merck will be happy to see some attention turning to its product pipeline in the midst of its painful drug liability lawsuits over withdrawn painkiller Vioxx (rofecoxib).