TABLE 5.

In vitro sensitivities of P. vivax, stratified by duration of assay and RT ratio prior to culturea

DrugQuadrant AQuadrant BQuadrant CQuadrant DP valued
No. of isolatesIC50 value(95% CI) for trophozoite majority and duration ≥30 hbNo. of isolatesIC50 value (95% CI) for ring majority and duration ≥30 hcNo. of isolatesIC50 value (95% CI) for ring majority and duration <30 hcNo. of isolatesIC50 value (95% CI) for trophozoite majority and duration <30 hb
Chloroquine18298 (153-583)3559.8 (34.8-103)25475 (296-762)75539 (387-751)<0.001*
Amodiaquine1516.5 (9.8-27.9)357.85 (5.31-11.6)2123.4 (15.6-35.0)7118.9 (14.2-25.0)0.001*
Artesunate141.20 (0.71-2.02)320.83 (0.56-1.23)181.39 (0.69-2.80)711.60 (1.23-2.09)0.06
Lumefantrine632.9 (5.59-193)537.6 (22.4-63.0)1024.8 (9.8-62.6)3314.6 (8.9-24.1)0.296
Mefloquine127.27 (3.84-13.8)307.26 (4.89-10.8)1222.2 (11.7-42.2)5317.4 (13.5-22.4)<0.001**
Piperaquine1329.1 (22.3-38.1)3014.6 (10.3-20.7)1431.2 (20.9-46.5)6722.9 (17.9-29.3)0.03***
  • a In vitro sensitivity of P. vivax for each drug (geometric mean IC50 [95% CI]) stratified by the duration of assay and the RT ratio prior to culture. Quadrants are the same subgroups as represented in Fig. 2.

  • b RT < 1; data on the initial parasite stage was unavailable for 20 isolates.

  • c RT ≥ 1; data on initial RT ratios were missing for two isolates.

  • d Overall between-group differences, by analysis of variance: *, group B versus A, C, or D, P = 0.001; **, group A or B versus C or D, P = 0.006; ***, group B versus A, C, or D, P = 0.026.