GlaxoSmithKline (GSK) and Crucell signed an agreement to co-develop a second-generation prime-boost malaria vaccine based on two of the companies’ existing candidates. The program aims to combine GSK’s Phase III RTS,S/AS malaria vaccine with Crucell’s early clinical-stage candidate Ad35-CS, which is based on the firm’s AdVac® technology and PER.C6® manufacturing platform.
The agreement follows on from previous preclinical data suggesting that when used in combination, the two vaccines elicit much greater immune responses against the circumsporozoite stage of the causative malaria agent, Plasmodium falciparum, than either candidate alone.
Under the terms of the deal Crucell and GSK will look for third-party funding to advance a prime-boost candidate based on Ad35-CS and RTS,S/AS into a Phase I/IIa trial in the U.S. Subject to successful completion of the study, the partners say that they will then aim to progress the vaccine into additional clinical trials, potentially with funding from public or nonprofit partners.
GSK teamed up with the PATH Malaria Vaccine Initiative (MVI) in 2001 to progress the pediatric clinical development of RTS,S in Africa, and a Phase III trial began in November 2009. The study, in seven African countries, is expected to involve up to 16,000 children. At the time, GSK said first regulatory submissions for the vaccine could be as early as 2012.
The RTS,S vaccine candidate was initially evaluated in U.S. volunteers during the mid-1990's as part of a collaboration with the Walter Reed Army Institute of Research (WRAIR). Crucell joined WRAIR and GSK in March 2003 under a CRADA to evaluate its AdVac malaria vaccine candidate both as a stand-alone vaccine and in combination with GSK's RTS,S vaccine candidate. It was these studies that confirmed the AdVac vaccine candidate efficiently primed and/or boosted malaria-specific immune responses.
Crucell’s malaria vaccine has also been supported by the NIAID since March 2004. The agreement is worth up to $3.5 million and covers process development of the AdVac-based candidate, including the production of clinical trial material. The AdVac35-CS vaccine started in Phase I trials during 2006.