MedicalResearch.com Interview with:
Gavin C.K.W. Koh, MB BChir MA PhD MCRP DTM&H
Department of Drug Discovery Unit for Diseases of the Developing World
GlaxoSmithKline | GSK
MedicalResearch.com: What is the background for this study?
Response: Malaria still remains one of the greatest global healthcare challenges so, as part of GSK’s efforts to fight diseases that disproportionately impact the poorest, we have been working on tafenoquine as a potential medicine for malaria for over 20 years. In 2008, GSK entered into a collaboration with the not-for-profit product development partnership, Medicines for Malaria Venture (MMV), to develop tafenoquine as an anti-relapse medicine for patients infected with a particular species of malaria called Plasmodium vivax malaria.
- vivaxmalaria is estimated to cause around 7.5 million clinical infections every year. The disease may cause fever, chills, vomiting, malaise, headache and muscle pain, and in some cases, can lead to severe malaria and be fatal.
Unlike other malaria species such as P. falciparum, P. vivax also has the ability to lie dormant in the liver from where it may periodically reactivate to cause relapses of P. vivax malaria. A single P. vivax infection may therefore give rise to multiple episodes of malaria, in the absence of a new mosquito bite. These relapses can occur weeks, months or even years after the initial infection. The dormant liver forms of the parasite cannot be treated with most other antimalarial treatments.
Another issue is that the only medicine currently available to stop the relapse is primaquine, a medicine approved in the 1950s, which must be given for 14 days. Given this length of treatment course, many people do not comply with the full course, which results in reduced effectiveness.
The aim of the DETECTIVE study was to look at the effectiveness of treatment in preventing relapse over six months with a 1-day course of tafenoquine, a 14-day course of primaquine, or placebo, with all patients also receiving a 3-day course of chloroquine, a medicine that is used to treat the initial infection.
MedicalResearch.com: What are the main findings?
Response: The DETECTIVE study met its primary endpoint. A significantly greater proportion of patients in the tafenoquine group did not have relapses compared to patients in the placebo group. A similar result was observed for the patients in the primaquine group compared to the placebo group. When considering the compliance issue of primaquine in the real-world setting, we saw that more than 95% of patients in the primaquine group took their treatment as instructed in the setting of a clinical study. From a safety perspective, adverse events from the study were consistent with the known safety profile of tafenoquine.
MedicalResearch.com: What should readers take away from your report?
Response: The positive results of the DETECTIVE study demonstrate the efficacy and safety of tafenoquine in an unprecedented single-dose for relapsing malaria. These data supported the approval of the medicine by the US Food and Drug Administration and Australia Therapeutic Goods Administration in 2018 marking it as the first new medicine for the radical cure of P. vivax malaria in more than 60 years. Having the data published in the NEJM will help other P. vivax malaria endemic countries as they strive towards malaria elimination.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: The DETECTIVE study was conducted in adult patients with P. vivax malaria and a significant part of the global burden of the disease is in children. GSK and MMV are therefore studying the use of tafenoquine in paediatric patients aged 6 months to 16 years (TEACH study). In addition, since vivax malaria in Indonesia is frequently resistant to chloroquine, we are conducting another study that is looking at tafenoquine plus dihydroartemisinin–piperaquine as the blood schizonticide (INSPECTOR study) in patients with P. vivax malaria in Indonesia.
Disclosures: The DETECTIVE study was supported by GSK and MMV.
Single-Dose Tafenoquine to Prevent Relapse of Plasmodium vivax Malaria
Marcus V.G. Lacerda, M.D., Alejandro Llanos-Cuentas, M.D., Srivicha Krudsood, M.D., Chanthap Lon, M.D., David L. Saunders, M.D., Rezika Mohammed, M.D., Daniel Yilma, M.D., Dhelio Batista Pereira, M.D., Fe E.J. Espino, M.D., Reginaldo Z. Mia, M.D., Raul Chuquiyauri, M.D., Fernando Val, Ph.D., et al.
January 17, 2019
N Engl J Med 2019; 380:215-228
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