Malaria in pregnancy has devastating consequences for mother and foetus. WHO recommends intermittent preventive treatment in pregnancy (IPTp) with sulphadoxine-pyrimethamine (SP) for asymptomatic women, but high-level parasite resistance to SP threatens its efficacy. Dihydroartemisinin-piperaquine (DP) has the potential to replace SP for IPTp. However, the DP strategy has not been found to be superior to SP for reducing the incidence of low birthweight (LBW), small-for-gestational age (SGA), or preterm birth. This may be the result of sulphadoxine having antibacterial properties; it is derived from sulphonamide, which have been used for decades to treat curable STIs/RTIs. However, SP is unlikely to be curative of STIs/RTIs, nor highly effective against malaria parasites. Thus, combination treatment that contains a more efficacious antimalarial and a more efficacious anti-STI/RTI may produce better birth outcomes. The investigators will therefore determine whether combining SP with metronidazole (MTZ) or, separately, DP with MTZ can improve birth outcomes more than SP alone, potentially paving the way for integrated control strategies that will reduce the dual burden of malaria and curable STIs/RTIs.

This is an individually-randomized, 3-arm, partially-placebo controlled superiority trial comparing the efficacy, safety and tolerance of IPTp-SP versus IPTp-SP with MTZ, or IPTp-DP with MTZ to reduce adverse birth outcomes attributable to malaria and curable STIs/RTIs in 5,436 women in the Nchelenge District of Zambia.

Title: Effects of metronidazole plus intermittent preventive treatment of malaria in pregnancy on birth outcomes: a randomised controlled trial in Zambia.

Short Title: The ASPIRE Trial - Aiming for Safe Pregnancies by Reducing Malaria and Infections of the Reproductive Tract

Background and rationale: Current interventions in sub-Saharan Africa to reduce the burden of malaria infection and curable STIs/RTIs in pregnancy are inadequate. Malaria infection during pregnancy is responsible for 20% of all stillbirths and 11% of neonatal deaths and is strongly associated with low birthweight (LBW), preterm birth, and small-for-gestational-age (SGA) babies. To protect against adverse pregnancy outcomes in malaria-endemic areas, the WHO recommends providing IPTp-SP to pregnant women at each scheduled ANC visit as directly observed therapy from the second trimester to delivery with at least one month between doses. However, the loss of parasite sensitivity to SP has compromised the efficacy of IPTp.

Apart from syphilis and HIV screening, the WHO recommends the syndromic management of curable STIs/RTIs in low- and middle-income countries involving diagnostic and treatment algorithms based on self-reported symptoms. BV and TV are included in these guidelines. However, syndromic management fails to detect the majority of infections in women for whom STIs/RTIs are most often asymptomatic. This is of genuine consequence in pregnancy. BV is the most common urogenital disorder in the world among women of reproductive age and increases the odds of preterm delivery 1.5-2 times. TV is the most prevalent curable STI in the world and increases the odds of preterm delivery 1.5 times. BV and TV both double the odds of LBW. Although vertical transmission of TV is uncommon, maternal treatment may prevent respiratory or genital infection of the newborn. These adverse pregnancy outcomes could be averted with metronidazole (MTZ); 2g is safe and curative of TV and reduces the recurrence of BV. Importantly, the dose can be provided as directly observed therapy during ANC to ensure compliance.

IPTp-DP is the leading candidate to replace IPTp-SP. A trial in Kenya showed that IPTp-DP was superior to IPTp-SP in preventing clinical malaria episodes and other malaria-related endpoints. Alongside the trial, the investigators will conduct sub-studies that will generate important data about the mechanisms of IPTp-SP action against malaria, BV and TV.

Primary objective: To determine if IPTp with SP or DP, combined with MTZ, for the control of malaria and STIs/RTIs in pregnancy is safe and superior to IPTp with SP alone for reducing adverse pregnancy outcomes.

Hypothesis: IPTp with SP or DP, combined with MTZ, is superior to IPTp with SP alone in preventing adverse pregnancy outcomes.

Overview Study Design: A 3-arm, parallel, partially placebo-controlled, individually randomised, phase-3, superiority trial involving 5,436 (1,812 per arm) pregnant women in ANC facilities of the Nchelenge District of Zambia.

An economic evaluation will be carried out alongside the trial to estimate the cost and cost-effectiveness of interventions. In addition, the acceptability of therapy and the trade-offs between different attributes of the trial arms will be assessed using a discrete choice framework among trial participants and health care providers.

Sub-study 1: Effect of treatment on vaginal and intestinal microbiome and maternal cytokines

Objective: To characterise the effect of treatment across trial arms on the vaginal and intestinal microbiota communities, vaginal and intestinal bacterial loads and soluble markers of inflammation.

Sub-study 2: In vitro testing of sulphadoxine and other antimicrobial agents (Ndola, Zambia)

Objective: To measure the drug sensitivity of several pathogens implicated with WHO syndromes of vaginal discharge, lower abdominal pain, or genital ulcers in the presence of sulphadoxine and other antimicrobial agents.

Sites: The study will be conducted ANC facilities of the Nchelenge District of Zambia where the prior pregnancy cohort was previously carried out, malaria transmission is high, parasite resistance to SP is high, and there is a high prevalence of TV and BV among pregnant women at antenatal care facilities.

Study Population: HIV-negative pregnant women (all gravidae) between 16 and 28 weeks' gestation, as assessed by ultrasound dating who have not yet started IPTp during the current pregnancy.

Study Interventions:

Group 1: IPTp-SP plus MTZ placebo* (control) Group 2: IPTp-SP plus MTZ* Group 3: IPTp-DP plus MTZ*

SP = 3 tablets each containing 500mg sulphadoxine and 25mg pyrimethamine (Day 0) MTZ = 4 tablets each containing 500mg as directly observed therapy (Day 0) DP = 3 tablets of 40mg of dihydroartemisinin and 320mg of piperaquine (Days 0, 1, 2)

*MTZ placebo (Group 1) and active MTZ (Groups 2 and 3) will be co-administered with SP or DP during the enrolment visit (gestational week 16-19) and the last ANC visit prior to delivery (gestational week 30-34)

Inclusion Criteria:

• Pregnant women
• HIV-negative
• Gestational age from Week 16 and 0 Days to Week 28 and 0 Days (measured by sonography)
• Carrying a single viable pregnancy
• Resident in the study area
• Express willingness to adhere to scheduled and unscheduled study visit procedures, and deliver at a trial facility

Exclusion Criteria:

• HIV-positive
• Carrying multiple pregnancies (twins, etc.),
• Known cardiac ailment
• Severe malformations or nonviable pregnancy observed by ultrasound
• History of receiving IPTp-SP during the current pregnancy
• Known allergy or contraindication to any of the study drugs
• Unable to give consent
• Concurrently participating in any other trial, including prior enrolment in this trial.

Individual participant data will be shared upon receiving formal request and subject to sharing agreement.

Five years

The full protocol will be available on request to any interested professional. All requests for data for secondary analysis will be considered by a Data Access Committee to ensure that use of data is within the terms of consent and ethics approval.

Partially placebo controlled