GlaxoSmithKline Plc’s experimental malaria vaccine was less effective in reducing illness in African infants than in older children in a study, suggesting further development will be necessary before wide distribution.
The shot, known as RTS,S, protected 31 percent of 6,537 children age six weeks to 12 weeks from developing symptoms over 12 months after receiving their third dose and it prevented 37 percent from suffering severe malaria, according to data from a late-stage study published today by the New England Journal of Medicine. That compares with 56 percent and 47 percent, respectively, in children age five months to 17 months, as reported by London-based Glaxo last year.
Glaxo will examine the different findings between the age groups, which may affect its strategy for filing the vaccine to regulatory authorities, the company said in a statement. RTS,S would be the first vaccine against malaria, which kills 655,000 people a year worldwide, mostly children under age five in sub-Saharan Africa.
“The efficacy came back lower than we had hoped,” Bill Gates, co-founder of the Bill & Melinda Gates Foundation, which contributed to the trial costs, said in a statement. “The trial is continuing and we look forward to getting more data to help determine whether and how to deploy this vaccine.”
Glaxo fell as much as 0.8 percent to 1,360 pence and was trading down 0.6 percent at 11:36 a.m. in London. The stock has declined 7.1 percent this year, valuing the drugmaker at 67.1 billion pounds ($107 billion).
Several factors may have contributed to the less positive results in infants, including the effect of maternal antibodies, the role of other childhood vaccines administered with RTS,S and the inclusion of trial sites in high-transmission areas, the study authors said in the published paper.
Glaxo will release more data by the end of 2014 on efficacy 30 months after the third dose as well as the effect of a booster dose, it said.
“It’s terribly important that we work hard to unlayer this onion,” Glaxo Chief Executive Officer Andrew Witty said on a conference call today. “There’s an awful lot of new data to come.”
There were 216 million cases of malaria globally in 2010, according to the World Health Organization. The mosquito-borne parasite of the human liver and blood causes fever, chills and flu-like symptoms, or shock, anemia and organ damage if untreated. Malaria is prevented now with insecticide-treated bed nets. Drugs are prescribed after infection.
The data published today are the second set of results from a study of 15,460 children in seven African countries that began in March 2009.
Children were given either RTS,S or a non-malaria vaccine combined with other childhood vaccines for diseases such as hepatitis B, polio, diphtheria and tetanus. Fever was reported more frequently in the RTS,S group, at 31 percent, compared with 21 percent in the control group, according to the study.
Two new cases of meningitis, a bacterial infection of the membranes covering the brain and the spinal cord, were reported in the younger infant group, in addition to the nine reported last year. Analysis revealed a bacterial cause of the meningitis in seven of the 11 cases.
“The results of this trial suggest that this candidate malaria vaccine is not ready to become part of the routine panel of infant immunizations,” Johanna Daily, professor at Albert Einstein College of Medicine’s Division of Infectious Diseases, said in a comment accompanying the published article. “However, this trial did show protection in a subset of children and thus should be used as an opportunity to enlighten researchers regarding the host responses that correlate with vaccine protection.”
Glaxo has said it plans to file for regulatory approval in 2014 and bring the vaccine to market as early as 2015. If the drug is approved, the Geneva-based WHO has said it would decide by 2015 whether to include the shot among its recommended childhood vaccines, which would enable the treatment to be included in national immunization programs.
The drugmaker hasn’t disclosed what it plans to charge for RTS,S, only that the eventual price would will the cost of making it plus 5 percent, which the company would reinvest in finding a second-generation malaria vaccine or preventive treatments for other neglected tropical diseases.