Vaccine Bill Brieger | 03 Nov 2009 08:38 am
Malaria vaccine enters phase 3 clinical trials
A new malaria control tool is closer to joining the arsenal of malaria interventions according to vaccine researchers and their sponsors at a press briefing today during the MIM 5th Pan-African Malaria Conference in Nairobi.
A joint venture between PATH’s Malaria Vaccine Initiative and GlaxoSmithKline Biologicals, with support from The Bill and Melinda Gates Foundation, WHO and African Governments and the participation of African malaria researchers at 11 sites in seven countries has recently completed a successful Phase 2 Clinical Trial of the RTS,S vaccine.
Mozambique, one of the Phase 2 trial sites reported that, “vaccine efficacy against new infections was 65 percent over a three-month follow-up period after the infants received all three doses of the vaccine. The results also showed that the vaccine reduced episodes of clinical malaria by 35 percent over a six-month follow-up period starting after the first dose.” At the Ghanaian study site it was confirmed that “Three dose schedules were more immunogenic than 2 dose schedules.”
Joe Cohen of GSK Biologicals explained at the press conference that vaccine efficacy in children 5-17 months was 53% after 8 months. The trials also showed that the new vaccine can be integrated into the EPI vaccine process. Continuing research will determine if it will also be effective in younger children.
Phase 3 trials have started and have already enrolled 5,000 of the expected 16,000 volunteer participants. Reporters were anxious to know when the vaccines might actually be available for general use. The panelists outlined steps that included filing results of Phase 3 and previous trials with regulatory agencies around 2012. If approved, vaccines could be available around 2015. In the meantime partners are gearing up to find funding to support adequate production.
Christian Loureq of the PATH Malaria Vaccine Initiative said that partners ranging from researchers, producers and funders were all thinking ahead. No one wants the vaccine to sit on the shelf after proving its efficacy. A decision making framekwork is helping planners identify the data and resources needed to start rolling our vaccines on the day they are approved.
As noted, the partners recognize that an effective vaccine will be only one of the needed interventions to sustain malaria control, especially since the efficacy, though good, is not perfect. Thus, they are already thinking about research for the next generation of vaccines for 2020 or 2025
A key component to planning roll-out is research for understanding the community perspective, recognizing that the mothers who brought their children to the trials are also central partners in this initiative. The EPI program itself is full of lessons about acceptance and dropping out. The 3-dose vaccine regimen will certainly pose many implementation challenges, but hopefully the malaria community will be ready to tackle these.