Addressing the bottleneck at clinical testing of candidate malaria vaccines

摘要

[Extract] Invited Commentary on 'Preerythrocytic and Blood-Stage Malaria Vaccines Can Be Assessed in Small Sporozoite Challenge Trials in Human Volunteers', Roestenberg et al., Journal of Infectious Diseases, 2012.\ud\udVaccines are a very effective health care intervention but are not available for many diseases, including malaria. Potential candidates have been identified in preclinical research studies and some have progressed through preclinical development to clinical trials (http://www.who.int/vaccine_research/links/Rainbow/en/index.html). However, the vaccine development pathway is long and expensive and there is a major bottleneck at the stage of clinical testing. For malaria, only a single candidate has advanced to Phase 3.1 Agnandji ST, Lell B, Soulanoudjingar SS, Fernandes JF, Abossolo BP, Conzelmann C, et al.. RTS,S Clinical Trials Partnership. First results of phase 3 trial of RTS,S/AS01 malaria vaccine in African children. N Engl J Med. 2011;365(20):1863–75. Moreover, rodent malaria models exist but protection against challenge with the causative parasites of human malaria can only be assessed in humans, and there are no known correlates of protective immunity to malaria. Candidate vaccines that fail to meet defined go/no-go criteria in animals during development may nonetheless exhibit efficacy in humans. The testing of a larger portfolio of vaccine candidates in small numbers of volunteers in clinical research studies would be valuable.