# Establishing the Kenya National Antivenom Quality Control Laboratory: Preclinical Efficacy Results of Four Antivenoms Against Venoms from the “Big Five” Snake Species in Kenya

## TL;DR

This study evaluates the effectiveness of four antivenoms in Kenya against venom from five dangerous snake species to improve snakebite treatment.

## Contribution

The study establishes a national antivenom quality control framework through preclinical testing of antivenoms in Kenya.

## Key findings

- SAIMR polyvalent, AFRIVEN, and PANAF-PremiumTM showed strong venom-neutralizing efficacy in both in vitro and in vivo tests.
- InoserpTM had poor binding and neutralizing performance, especially against Naja and Dendroaspis venoms.
- The results support the need for a national antivenom quality control laboratory to ensure effective treatment options.

## Abstract

Antivenom administration is currently the only therapy for snakebite envenoming. However, in sub-Saharan Africa, inadequate quality control systems have led to deficits in the availability, accessibility, efficacy and safety of regionally available antivenoms, which, in turn, hinder snakebite treatment and management in the region. To address this impediment to snakebite treatment in Kenya, this study aimed to assess the preclinical neutralising potencies of four different antivenoms previously or currently available in Kenya (SAIMR polyvalent, AFRIVEN, PANAF-PremiumTM and InoserpTM) against key snakes of medical importance in the region, towards establishing a national antivenom quality control laboratory. Venoms were extracted from the Kenyan “big five” medically important snake species: Naja ashei, Naja pallida, Naja nigricollis, Dendroaspis polylepis and Bitis arietans, and their lethal potencies were determined using a murine median lethal dose (LD50) assay. In vitro immunological assays (ELISAs and immunoblotting) and an established preclinical murine in vivo neutralisation assay (median effective dose [ED50]) were used to assess the immunoglobulin-binding and venom-neutralising efficacies of the test antivenoms. In vitro assays revealed high venom-binding titres of SAIMR polyvalent, AFRIVEN and PANAF-PremiumTM, and reactivity to a wide range of venom proteins across the different snake venoms. Contrastingly, InoserpTM antivenom had low binding titres and poor reactivity to the snake venom proteins. These findings were aligned with the in vivo results, where SAIMR polyvalent, AFRIVEN and PANAF-PremiumTM showed potent venom-neutralising efficacies against all the tested snake venoms, while InoserpTM had low potency and failed to neutralise the lethal effects of N. ashei, N. pallida and D. polylepis venoms at the manufacture-claimed doses. Based on these robust preclinical results, we conclude that SAIMR polyvalent, AFRIVEN and PANAF-PremiumTM antivenoms offer considerable potential for the treatment of envenoming by diverse medically important snakes in Kenya. The observed deficiencies with the InoserpTM product highlight the importance of (i) robust, independent preclinical antivenom efficacy testing and (ii) the value of establishing a quality control laboratory to inform local regulatory and procurement decision making.