A phase III trial to test the effectiveness of PRO2000/5

How well does a microbicide gel work to prevent HIV infection, and how safe is it?

What was this study about?

The majority of the 25 million adults in sub-Sahara Africa infected with HIV are women. Microbicides are a new range of products under development which might prevent transmission of HIV and other sexually transmitted infections (STIs) when used before sex.

They will be useful for people who cannot, or do not want to, practise abstinence or use condoms. They will be affordable, easy to use and of particular value to women, especially in developing countries where the incidence of HIV-AIDS and other STIs is high.

The Microbicides Development Programme (MDP) is a partnership to develop vaginal microbicides for the prevention of HIV transmission. It brings together academic institutions, non-profit organisations and pharmaceutical companies. The MDP aims to:

  1. Undertake a trial to test the effectiveness of a candidate microbicide in Africa, PRO2000 vaginal gel at two strengths compared to placebo gel.
  2. Conduct social science research into acceptability and barriers to the uptake of microbicides that will subsequently facilitate marketing and access to a successful gel.
  3. Evaluate new microbicide products in safety studies in the UK and Africa.

The MDP301 trial will test how effective the PRO 2000/5 microbicide gel is at preventing vaginally acquired HIV infection, and how safe the gel is.

What difference did this study make?

Unfortunately there was no evidence that the gel offered any protection against HIV at either the 0.5% or 2% strength. This study provided the definitive answer to the question and ended the product development of PRO2000.

Thousands of women were screened for HIV in the preparation for and execution of this large study and the knowledge they gained about HIV and about their health in general was empowering. There was an extensive social science programme and as a result there is a better understanding of how women incorporated the gel in their usual routine, the challenges they faced and how they overcame these.

The data generated were used for subsequent analyses including an evaluation of the risk of injectable hormonal contraception compared to no contraception and the prevalence and incidence of bacterial sexually transmitted infections in Sub-Saharan Africa.


 The main paper describing the safety and effectiveness of PRO2000 vaginal gel is here.


Description of the continuous informed consent methods used in MDP301.


A paper describing the mixed methods and triangulation model employed for assessing adherence to gel, and a follow up paper describing the accuracy of the outputs from the model and consequent understanding of adherence in MDP301.


Description of the novel HIV testing algorithm used in MDP301.


Secondary analysis assessing association between hormonal contraception and the risk of acquiring HIV.

Type of study

Randomised trial

Contact details

Who funded the study?

The trial was funded by the UK Department for International Development and the MRC and administered by the MRC Clinical Trials Unit and Imperial College London.

When did it take place?

This trial started recruiting women in October 2005. Recruitment closed on the 15th of August 2008 and follow up was completed on 18th September 2009.

Where did it take place?

Recruitment took place in Tanzania, Uganda, Zambia and three sites in South Africa.

Who was included?

We recruited 9,404 sexually active women, 9,385 of whom had at least one HIV test in follow-up and contributed to the analysis.