Human African trypanosomiasis

Research

Development of new diagnostic tools

For effective control and surveillance of sleeping sickness, new tests are needed. New diagnostic tests should be affordable, implementable with simple protocols at any health structure level requiring minimum training and equipment, allowing its easy execution by any health worker.

They should provide rapid and reliable results with optimal sensitivity and specificity, for an uncontroversial diagnosis of both forms of the disease. This should enable immediate treatment, avoiding cumbersome parasitological examinations.

In addition, the tests should be stable at room temperature, requiring no refrigeration and having a reasonable volume for easy storage and transport.

WHO HAT Specimen Bank

As part of its contribution to support diagnostics research, WHO has set up a HAT specimen bank. This makes biological samples of patients, (including non-infected controls from the same population, and serological suspects of HAT) available to research institutions working for the development of new diagnostic tests. The aim is to provide reference clinical materials to research institutions to develop and evaluate new tests for diagnosis and staging of HAT, appropriate for use in low-income countries. The central repository of the samples is located at the Institut Pasteur of Paris (ICAReB).

Requests of samples should be made to :

Dr Gerardo Priotto
Department of Control of Neglected Tropical Diseases
World Health Organization
Telephone: +41 22 791 1375
E-mail: priottog@who.int

Dr Jose Ramon Franco
Department of Control of Neglected Tropical Diseases
World Health Organization
Telephone: +41 22 791 3313
E-mail: francoj@who.int

Efforts to develop new molecules

A major issue for ensuring sustainability of control continues to be the complexity of current therapies. There is a need to develop a new therapeutic tool which will not require any particular skills or care to administer, with a regimen lasting a few days, making it manageable by peripheral health staff working in rural areas.

Ideally new drugs should be:

  • Effective in both forms of the disease and in both stages, making lumbar puncture unnecessary;
  • Safe
  • Stable at room temperature;
  • Having a reasonable volume for easy transport and storage, allowing the integration of patient management in the regular health system.
  • Affordable by national health systems and patients of endemic countries.

An added problem in the research of new molecules is the numerous challenges of conducting clinical trials for HAT in the field. WHO organized an informal consultation to develop a consensus framework for clinical trials, which safeguards quality data and standardizes methods to permit direct comparability of data.

Clinical trials in phase II/III of a new molecule called fexinidazole are ongoing. Fexinidazole is a nitroimidazole which has shown its efficacy at preclinical stage. It is being investigated for possible future use as an oral drug in early and late stages of both forms of HAT. The Drugs for Neglected Diseases initiative (DNDi) receives funding from the Bill and Melinda Gates Foundation to undertake this clinical development.

A new oral drug candidate, the oxaborole SCYX-7158 has shown promising results in pre-clinical and phase I clinical studies and it is planned to advance soon to phase II and III studies. Oxaborole is expected to be administered as a single oral dose, for both disease stages, which would dramatically simplify the current treatment.