TABLE 17 Protective Efficacy (PE) and Reported 95% Confidence Intervals (CI) for Outcomes from Randomization Through 11 Months After Last Dose of SP or Placebo

Location, Country

Ifakara, Tanzania

Navrongo, Ghana

Manhiça, Mozambique

Overall

Number of Subjects

Placebo

351

1225

748

 

IPTi-SP

350

1221

755

 

Episodes of Clinical Malaria

Placebo

259

1871

576

 

IPTi-SP

180

1570

564

 

% PE

32

16

2

17

95 CI (%)

(14, 47)

(4, 26)

(−20, 20)

(0.8, 30)

p-value

0.002

0.007

0.84

0.04

Episodes of Hospitalization with Malaria Parasites

Placebo

71

122

102

 

IPTi-SP

42

83

108

 

% PE

42

32

−3

26

95 CI (%)

(12, 62)

(5, 51)

(−56, 32)

(−0.9, 46)

p-value

0.011

0.023

0.89

0.057

Episodes of All-Cause Hospital Admissions

Placebo

226

561

402

 

IPTi-SP

191

513

379

 

% PE

16

8

13

12

95 CI (%)

(−6, 34)

(−10, 23)

(−10, 31)

(0.2, 22)

p-value

0.14

0.36

0.25

0.046

Subjects with Anemia

Placebo

52

274

108

 

IPTi-SP

42

263

119

 

% PE

23

4

8

9

95 CI (%)

(−11, 47)

(−19, 22)

(−16, 28)

(−6, 21)

p-value

0.16

0.73

0.47

0.22

SOURCE: Compiled from data in the report of the Consortium’s Statistical Working Group (IPTi Consortium, 2008f).

The IOM committee was aware that it had available for deliberations more data and analyses than had been available to other independent committees that had previously assumed the task of reviewing and assessing the efficacy of IPTi-SP. Nevertheless, we were sensitive to the fact that some of the most important analyses we reviewed were from reports that had not yet been published.

Finding about heterogeneity of IPTi-SP studies: The committee found that the six IPTi-SP studies differed in their settings, intensity and seasonality of malaria transmission, use of insecticide-treated bed net coverage, prevalence of SP resistance and age at administration of doses of SP (or of placebo). The committee viewed this heterogeneity as a positive feature of the set of trials, concluding that IPTi-SP has been evaluated in several venues within sub-Saharan Africa that have different conditions, which allows generalizability to other sites in sub-Saharan Africa that have high or moderate intensity of transmission. Analysis of results from the different sites both shows the generalizability of IPTi-SP and identifies limitations that might not be detected if the conditions were more homogeneous.


Conclusion about efficacy data: The committee concluded that the trials had adequate power to assess the effect of IPTi-SP on the number of episodes of clinical malaria.



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