Oral Presentation 8th International Conference on Plasmodium vivax Research 2022

Results of the First Phase of an Operational Feasibility Study (TRuST) of Appropriate Plasmodium Vivax Radical Cure with Tafenoquine or Primaquine after Quantitative G6PD Testing in Brazil (80306)

Marcus Lacerda 1 , Dhelio B Pereira 2 , Marcelo Brito 1 , Rosilene Ruffato 2 , Felipe Murta 1 , Vanderson Sampaio 1 , Catherine Lucena 2 , Patricia Carvalho 1 , Francisco E Ferreira 3 , Liane Blume 3 , Alexandre Menesez 4 , Roberta Ataides 4 , Elodie Jambert 5 , Penny Grewal Daumerie 5 , Stephan Duparc 5
  1. Tropical Medicine, Doctor Heitor Vieira Dourado Tropical Medicine Foundation, Manaus, Amazonas, Brazil
  2. Tropical Medicine, Centro de Pesquisa em Medicina Tropical de Rondônia (CEPEM), Porto Velho, Rondônia, Brazil
  3. General Coordination for the Surveillance of Zoonoses and Vector-Transmitted Diseases (CGZV), Ministry of Health, Brasilia, Brazil
  4. Global Health Strategy, Rio de Janeiro, South Rio Grande , Brazil
  5. Medicines for Malaria Venture, Geneva, GVA, Switzerland

Tafenoquine (TQ) was approved by US-FDA and Australian-TGA in 2018. TQ is also approved in Brazil, by the Brazilian Health Regulatory Agency (ANVISA). The municipalities of Manaus (Amazonas) and Porto Velho (Rondônia), officially adopted the use of quantitative-G6PD tests before the radical cure of P. vivax (primaquine (PQ) or TQ) and TQ as first-choice treatment for radical cure of P. vivax in patients ≥16 years after G6PD test.

This is a non-interventional, observational study, the primary objective investigates whether P. vivax patients are treated with TQ in accordance with the appropriate level of G6PD activity while the main secondary objective investigates the same endpoint with PQ.

The study is being conducted in a phased manner with a 1st phase in higher-level health facilities (referral hospitals, hospitals, emergency care units, polyclinics). After review of the interim results by an Independent Study Oversight Committee (ISOC), a 2nd phase may start in lower-level health facilities (basic health units, basic family health units and primary care).

This interim analysis was conducted on data collected from 09/09/21 to 18/10/21 at 9 high and medium-level health facilities (Manaus 5, Porto Velho 4). At the date of data cut-off, 600 patients were included in the Analysis Population, 381 treated with TQ, 203 with PQ and 16 not treated with TQ or PQ.

The percentage of P. vivax patients treated or not with the drugs in accordance with the appropriate level of G6PD was better with TQ than with PQ. Among the patients treated with TQ, no cases of Acute Haemolytic Anaemia (AHA) were detected, while 5 cases of AHA were identified in patients treated with PQ. Detailed results will be presented during the conference.

ISOC members met mid-December 2021 and concluded the second phase of the study can start in lower-level facilities as planned in the protocol.