Treatment Efficacy of Dihydroartemisinin-Piperaquine for Uncomplicated Plasmodium falciparum and Plasmodium vivax Malaria in Timika, Papua, Indonesia

Dihydroartemisinin-piperaquine (DP), the first-line treatment for uncomplicated malaria in Timika, Papua, Indonesia, has also been used for intermittent preventive treatment in pregnancy (IPTp-DP) since February 2022. Concerns about the potential emergence of drug resistance associated with this dual policy prompted the present study, which was conducted to assess DP efficacy in treating uncomplicated Plasmodium falciparum (P. falciparum) and Plasmodium vivax (P. vivax) malaria in the general population 15 months after IPTp-DP was introduced. Between May and December 2023, the current study recruited 75 P. falciparum and 75 P. vivax malaria patients, who received supervised DP treatment for 3 days. Clinical and laboratory data were collected daily (on days 1, 2, 3, and 7) and then weekly for 6 weeks. Molecular analysis was performed to detect genetic markers of P. falciparum resistance to DP and distinguish between recrudescence and reinfection. A total of 68 P. falciparum and 58 P. vivax patients completed their day 42 follow-up. The cumulative risk of same-species recurrence by day 42 was 1.5% (95% CI: 0-7.9%) in P. falciparum patients (polymerase chain reaction-adjusted) and 5.2% (95% CI: 1.1-14.1%) for P. vivax patients (unadjusted). No patients exhibited parasitemia on day 3. No P. falciparum isolates carried kelch 13 gene mutations or exhibited increased plasmepsin 2-3 copy numbers on either day 0 (0/75) or at recurrence (0/2). At the current level of IPTp-DP coverage (824 doses administered), there was no evidence of high treatment failure rates or the selection of resistant parasites in patients with uncomplicated malaria treated with DP. Continuous monitoring of DP efficacy remains crucial for both treatment and chemoprevention.