Comment on 'The clinical pharmacology of tafenoquine in the radical cure of Plasmodium vivax malaria: An individual patient data meta-analysis'.

A single 300 mg dose of tafenoquine, in combination with chloroquine, is currently approved in several countries for the radical cure (prevention of relapse) of Plasmodium vivax malaria in patients aged ≥16 years. Recently, however, Watson et al. suggested that the approved dose of tafenoquine is insufficient for radical cure, and that a higher 450 mg dose could reduce P. vivax recurrences substantially (Watson et al., 2022). In this response, we challenge Watson et al.'s assertion based on empirical evidence from dose-ranging and pivotal studies (published) as well as real-world evidence from post-approval studies (ongoing, therefore currently unpublished). We assert that, collectively, these data confirm that the benefit-risk profile of a single 300 mg dose of tafenoquine, co-administered with chloroquine, for the radical cure of P. vivax malaria in patients who are not G6PD-deficient, continues to be favourable where chloroquine is indicated for P. vivax malaria. If real-world evidence of sub-optimal efficacy in certain regions is observed or dose-optimisation with other blood-stage therapies is required, then well-designed clinical studies assessing safety and efficacy will be required before higher doses are approved for clinical use.

Malaria radical cure opportunity assessment in India: Discussing opportunities through stakeholder convening workshop and recommendation for improved access to malaria treatment.

India contributes to over 40% of the global Plasmodium vivax disease burden, and P. vivax contributes to approximately one-third of all malaria in India. Government of India has set goals to eliminate malaria by 2030. Doing so will require scaling up existing and new strategies, treatments and diagnostic tools. Access to appropriate diagnosis and treatment for P. vivax malaria is currently limited, and it is unclear how new tools will be rolled out. To support the government in its malaria elimination efforts, the current challenges associated with access to best clinical management of vivax malaria must be understood and mitigated to effectively deploy new tools and scale up existing solutions. The recent Food and Drug Administration (US-FDA) as well as Therapeutics Goods Administration (Australian TGA) approval of tafenoquine, developed by GSK GlaxoSmithKline and Medicines for Malaria Venture (MMV) as a new single-dose radical cure treatment for P. vivax malaria, and the commercial availability of new point-of-care glucose-6-phosphate dehydrogenase (G6PD) tests provide new opportunities to improve clinical management of vivax malaria in India. This report discusses the background, objectives, implementation strategies, and next steps that came out of the Stakeholder Workshop on Malaria Radical Cure in New Delhi, India on 4 February 2019. The focus was to understand the risks and opportunities associated with access to best clinical practices for managing vivax malaria in India. A key outcome was to propose a framework for articulating and segmenting important investment opportunities for improving access to best clinical practices for P. vivax radical cure in India.