Study profile
At enrolment, a total of 743 patients were screened of whom 520 were randomized to receive either PA (224) or AL (296). These first malaria episode groups constituted the first treatment groups with study drugs or baseline groups. During the two-year follow-up period, 14 participants in the PA arm and 26 ones in the AL arm were definitely excluded from the study. Reasons leading to these exclusions are given in Figure 1. In this intention to treat analysis, 859 subsequent malaria episodes were retained over the study period with 336 in the PA arm and 523 in the AL group as shown in figure 1.
Baseline characteristics of the study population
General characteristics of the study population at enrolment are described in table 1. Mean age of participants was 8.96 ± 6.52 years in the PA arm versus 9.29 ± 7.56 years in the AL arm. Participants from the age group 5 to 15 years were predominant in both study arms, accounting for 61.61% in the PA arm versus 57.77% in the AL group. Among common presenting symptoms, headache was predominant with 80.36% and 72.97% in the PA and AL arms, respectively; Malaria was mainly due to Plasmodium falciparum (Pf) which caused 99.11% of infections in the PA arm and 98.31% in the AL arm. Globally, in each treatment arm, individual mean values of hepatic parameters and that of hemoglobin concentration at baseline were similar between study groups, as shown in table 1.
Non-clinical hepatic adverse events
At the end of the 2-year follow-up period, from a total of 1379 recorded malaria episodes, 324 hepatic adverse events were registered with a prevalence of 23.5%. Elevated ALT followed 3.05% (40/1379) of all treated malaria episodes, elevated AST 3.34% (46/1379), elevated ALP 1.81% (25/1379), and elevated total and direct bilirubin with 7.90% (109/1379) and 7.40% (102/1379) respectively. More than half (55.25%) of these events (179/324) were recorded in the AL arm. Specific distributions of these adverse events according to the episode groups (first versus subsequent episodes) over study arms are given in figures 2 and 3. Proportions of elevated ALT and AST were low in both study arms, globally (figure 2). Retreatment groups in AL and PA arms were less likely to experience elevated ALT and elevated AST than the first episode groups; In the AL arm, 0.95%, 95%CI (0.39;2.27) of elevated ALT were registered during subsequently treated malaria episodes versus 3.71%, 95%CI (2.06; 6.58) during the first treated episodes, p=0.008. In the PA arm also, less elevated ALT was recorded in the retreatment group (2.67%, 95%CI (1.39; 5.07)) than the first episode group (7.58 %, 95%CI (4.76; 11.87), p=0.012. In addition, the proportion of elevated AST among subsequently treated participants with AL was lower (1.14%, 95%CI (0.51;2.53)) than that found among first episode treated participants (6.08% 95%CI (3.86;9.45)), p<0.001. In contrast, although the proportion of elevated AST was also lower in the retreatment group of the PA arm (3.27%, 95%CI (1.82;5.82)) than that of first treatment group (4.91% 95%CI (2.73;8.65), there was no evidence of a significant difference between these proportions, p=0.377.
In direct comparison of the proportions of elevated ALT among retreated participants in both study arms, there was no evidence of any significant difference between AL (0.95%) versus PA (2.67%) arms, p=0.058. Similarly, there was a weak evidence of significant difference between the proportions of elevated AST in participants retreated with PA (3.27%) and with AL (1.14%), p= 0.042.
Figure 3 shows a global increased trend of the proportions of elevated total bilirubin, elevated direct bilirubin and elevated ALP in retreatment groups in both study arms comparatively to first episode groups.
In the AL arm, the proportion of elevated total bilirubin in the retreatment group was higher (9.56%, 95%CI (7.31;12.39)) than that of first treatment group (4.72%, 95%CI (2.81;7.83)), p=0.014. In the PA arm, the proportions of elevated total bilirubin were similar between first episode group (6.70%, 95%CI (4.07;10.82)) and subsequent episodes group (8.92%, 95%CI (6.30;12.49)), p= 0.428.
There was also no evidence of significant difference between the proportions of elevated direct bilirubin in the first treatment groups and the retreatment groups in both AL (5.06%, 95%CI (3.07;8.24) vs 8.80% 95%CI (6.64;11.54) respectively, p= 0.053) and PA (5.35% 95%CI (3.06;9.20) vs 8.63% 95%CI (6. 05;12.15) respectively, p= 0.145) arms. Similarly, there was also no evidence of significant difference between the proportions of elevated ALP in the first treatment group in the AL arm (1.01%, 95%CI (0.32;3.09)) and the retreatment group (2.10%, 95%CI (1.16;3.76)), p=0.40, as well as in the PA arm between 1.78%, 95%CI (0.67;4.66) in the first treatment group versus 2.08%, 95%CI (0,99;4.31) in the retreatment group, p=1.0.
In direct comparison, proportions of elevated direct bilirubin, elevated total bilirubin and elevated ALP among retreated participants in both study arms were similar. There was no evidence of any significant difference between proportions of elevated direct bilirubin in retreated participants with AL (9.56%) versus PA (8.92%) arms, p=0.810. The proportions of elevated direct bilirubin in retreated participants in the AL arm (8.80%) was close to that of the PA arm (8.63%), p=1.00. Similarly, the proportion of elevated ALP after retreatment with AL and that of those retreated with PA was all alike with 2.10 % in the PA arm versus 2.08% in the PA arm, p= 1.00.
Serious hepatic adverse events correlation
In figure 4, participants’ row total bilirubin was correlated with ALT and AST to identify extreme values and serious hepatic adverse events that fulfilled the Hy’s law criteria in first treatment versus retreatment groups. The top and bottom right quadrants in the retreatment group appear with significant fewer extreme values compared to the first treatment group. Only one case fulfilling Hy’s Law criteria was identified among participants of the first treatment group in the PA arm. This Hy’s law case refers to a three year’s old girl without any clinical manifestation of liver injury. Her liver function parameters (ALT/AST) and the total bilirubin went back to the normal ranges after 21 days. This girl has been mistakenly retreated 4 months later with no more significant hepatic adverse event.
Retreatment association with non-clinical hepatic AEs
Table 2 shows the crude association of each non-clinical hepatic adverse events with retreatment with AL and PA. Elevated ALT and elevated AST were 65% and 82% less likely to occur in participants retreated with AL with adjusted odds ratios (aOR) equal to 0.25, 95%CI (0.08; 0.72) for elevated ALT and 0.18, 95%CI (0.07; 0.45) for elevated AST. These participants were also 2 times more likely to have elevated total bilirubin compared to the participants of the first treatment group, aOR=2.13 95% CI (1.15; 3.92). There was no evidence of significant association between retreatment with AL and elevated ALP and elevated direct bilirubin.
In the PA arm, participants in the retreatment group were 67% less likely to experience elevated ALT compared to those of the first treatment group, aOR=0.33, 95%CI (0.14; 0.76). Retreatment with PA was not significantly associated with neither elevated AST, elevated ALP nor elevated total and direct bilirubin.
After adjusting for age and gender retreatment with AL was significantly associated with elevated ALT, elevated AST, and elevated total bilirubin. Furthermore, in the AL arm, participants in the retreatment group were 76% and 84% less likely to have elevated ALT (aOR=0.24, 95% CI (0.08; 0.70)) and elevated AST (aOR= 0.16, 95% CI (0.06; 0.41)) respectively than those of the first treatment group. Each unit increase in participants’ age was associated with 17% reduced chance to present with elevated AST, aOR=0.87, 95%CI (0.73;0.93).
In addition, participants in the retreatment group were 2 times more likely to experience elevated total bilirubin, aOR=2.48, 95% CI (1.31; 4.69). Each unit increase in participants’ age was associated with 5% more chance to present with elevated total bilirubin (aOR=1.05 95%CI (1.02; 1.09)) as shown in table 3.
After adjustment, retreatment with PA was significantly associated with elevated ALT and total bilirubin. In fact, participants who were retreated with PA were 68% less likely to experience elevated ALT compared to participants of the first treatment group, aOR=0.32, 95%CI (0.14; 0.74). Repeatedly treated participants of this arm were also 2 times more likely to present with elevated total bilirubin compare to those from the first treatment group, aOR=2.09, 95%CI (1.01; 4.29). In addition, each unit increase in participants’ age was associated with 12% more chance to present with elevated total bilirubin, aOR was 1.12, 95%CI (1.07; 1.17). However, there was no evidence of significant association of elevated AST with retreatment with PA, aOR=0.59, 95%CI (0.25; 1.41) as shown in table 4.