Clinical trial NCT05150808: Vectron T500 (Broflanilide 50WP) for IRS in Tanzania Tanzania
Official title: WHO Phase III Evaluation of Vectron T500 (Broflanilide 50WP) for IRS in Tanzania
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: PHASE3
Conditions: Malaria,Falciparum
Keywords: vector control
insecticide
indoor residual spraying of mosquitoes
Lead sponsor: London School of Hygiene and Tropical Medicine
Sponsor class: OTHER
Collaborators: name: National Institute for Medical Research, Tanzania
name: Kilimanjaro Christian Medical Centre, Tanzania
First posted: 2021-12-09
Enrollment: 12500
Sex: ALL
Minimum age (years): 6
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Cluster Randomised Trial
Primary purpose: PREVENTION

Brief summary: Malaria is a major public health problem in Africa. An important way to control the disease is by Indoor Residual Spraying of insecticide in houses. Insecticide resistance has become a major problem. This trial will evaluate a novel insecticide against those insecticide resistant mosquito vectors in Tanzania E Africa.

Detailed description: Background: Indoor residual spraying (IRS) is one of the major methods of malaria vector control across sub-Saharan Africa, responsible for reducing malaria incidence by 10% since 2000. However, effective vector control is increasingly threatened by the rapid spread of insecticide resistance. Consequently, there have been investments in the development of new insecticides for IRS that possess novel modes of action with long residual activity, low mammalian and environmental toxicity and minimal cross-resistance. VECTRONTM T500, a new IRS insecticide containing the active ingredient broflanilide 50% WP, has been shown to be efficacious against both pyrethroid-susceptible and -resistant vector strains on mud and concrete substrates in phase II experimental hut trials in Tanzania.

Method: A two-arm non-inferiority cluster randomized controlled trial will be conducted in Muheza District, Tanga Region, Tanzania. VECTRONTM T500 will be compared to the IRS formulation Fludora® Fusion (active ingredients: clothianidin 50% WP + deltamethrin 6.25% WP). The predominant malaria vectors in the study area are pyrethroid-resistant Anopheles gambiae s.s., An. arabiensis and An. funestus s.s. Sixteen selected clusters of 75-200 households in each cluster will be pair-matched on baseline vector densities and allocated to reference and intervention arms. Consenting households in the intervention arm will be sprayed with VECTRONTM T500 and those in the reference arm will receive Fludora® Fusion. Monthly CDC light traps will collect mosquitoes to determine vector density, indoor biting, sporozoite and entomological inoculation rates (EIR). Phenotypic resistance to IRS active ingredients will be assessed using CDC bottle bioassays. Molecular and metabolic resistance mechanisms will be characterised among Anopheles field populations from both trial arms. Residual efficacy of both brands of insecticide will be monitored for 12 months post-spraying. A semi-structured questionnaire and focus group discussions will explore social and cultural factors that influence acceptability, perceived adverse effects and benefits of IRS.

Discussion: This protocol describes a phase III non-inferiority evaluation of a novel IRS product to reduce the density and EIR of pyrethroid-resistant Anopheles vectors. If VECTRONTM T500 proves non-inferior to Fludora® Fusion, it may be considered as an additional vector control product for malaria prevention and insecticide resistance management schemes.

Eligibility criteria: Inclusion Criteria:

All households who consent to IRS malaria control

Exclusion Criteria:

none

Primary outcomes:
measure: Vector density
timeFrame: 12-15 months
measure: Sporozoite rate
timeFrame: 12-15 months
measure: Entomological inoculation rate EIR
timeFrame: 12-15 months
Secondary outcomes:
Other outcomes:
Locations:
city: Muheza
country: Tanzania
facility: National Institute of Medical Research
city: London
country: United Kingdom
facility: London School of Hygiene & Tropical Medicine
Study officials:
References:
citation: Tungu PK, Rowland MW, Messenger LA, Small GJ, Bradley J, Snetselaar J, Kirby MJ, Mbewe NJ. Large-scale (Phase III) evaluation of broflanilide 50WP (VECTRON T500) for indoor residual spraying for malaria vector control in Northeast Tanzania: study protocol for a two-arm, non-inferiority, cluster-randomised community trial. BMC Infect Dis. 2022 Feb 21;22(1):171. doi: 10.1186/s12879-022-07138-3.