Tafenoquine trial is the first MMV study to enrol South American patients
In collaboration with MMV, GSK is evaluating the safety and efficacy of tafenoquine, the lead investigational medicine for the treatment of P. vivax (relapsing) malaria. This phase IIb clinical trial spans four malaria-endemic countries: Thailand, India, Peru and Brazil – the first Peruvian patients were recruited in September 2011 and the first Brazilian patients last week.
This trial breaks new ground for MMV with the enrolment of the first-ever patients from South America into an MMV supported trial. So far, 232 patients, of the 324 needed for the trial, have been recruited. The four countries selected suffer particularly high burdens of malaria; in Brazil alone there were more than two and a half million suspected cases of malaria in 2010, mostly attributable to P. vivax.1 In addition, each country hosts clinical trial sites with the capability and facilities to conduct GCP trials and follow-up patients for 6 months, which is important given the relapsing nature of P. vivax malaria.
While P. falciparum is the most deadly species of malaria parasite, P. vivax has proven the most elusive to cure. The P. vivax parasite has an uncanny ability to remain dormant in the liver of its host in a form known as the hypnozoite. This liver-stage form can reactivate any time between 3 weeks and several years – leaving its victims vulnerable to relapse into the feverish symptoms of malaria at any time and without warning.
Tafenoquine has the potential to cure the dormant liver form of P. vivax malaria (hypnozoites), thus preventing future relapses. It is an 8-aminoquinoline, of the same family as primaquine (current standard of care for relapse prevention), with demonstrated activity in patients. It is being developed as a potential single-dose treatment, which would be a significant improvement on the current 14-day course of primaquine.