Executive summary and recommendations from the WHO/UNAIDS/IAVI expert group consultation on 'Phase IIB-TOC trials as a novel strategy for evaluation of preventive HIV vaccines', 31 January-2 February 2006, IAVI, New York, USA

Jim Ackland, Susan Allen, Daniel Barth-Jones, Deborah Birx, Elwyn Chomba, Gavin Churchyard, Ann Duerr, Shuigao Jin, Margaret Johnston, Patricia E. Fast, Alan Fix, Mary Foulkes, Dean Follmann, Raymond Hutubessy, Siobhan Malone, Ronald H Gray, Abhay Indrayan, Jonathan Levin, Bonnie J. Mathieson, Timothy D. MastroJohn McNeil, Saladin Osmanov, Punnee Pitisuttithum, Barry Peters, Etienne Karita, Michael N. Robertson, R. Ramakrishnan, Helen Rees, Wasima Rida, Yuhua Ruan, Eric Sandström, Claudia Schmidt, Peter Smith, Steven Self, Georges Thiry, Judith Wasserheit, Frances Priddy, Ibou Thior, Mitchell Warren, David Cooper, Pontiano Kaleebu, Ruth Macklin, Godfrey Tangwa

Research output: Contribution to journalArticle


This report summarizes the discussions and recommendations from a consultation held in New York City, USA (31 January-2 February 2006) organized by the joint World Health Organization-United Nations Programme on HIV/AIDS HIV Vaccine Initiative and the International AIDS Vaccine Initiative. The consultation discussed issues related to the design and implementation of phase IIB 'test of concept' trials (phase IIB-TOC), also referred to as 'proof of concept' trials, in evaluating candidate HIV vaccines and their implications for future approval and licensure. The results of a single phase IIB-TOC trial would not be expected to provide sufficient evidence of safety or efficacy required for licensure. In many instances, phase IIB-TOC trials may be undertaken relatively early in development, before manufacturing processes and capacity are developed sufficiently to distribute the vaccine on a large scale. However, experts at this meeting considered the pressure that could arise, particularly in regions hardest hit by AIDS, if a phase IIB-TOC trial showed high levels of efficacy. The group largely agreed that full-scale phase III trials would still be necessary to demonstrate that the vaccine candidate was safe and effective, but emphasized that governments and organizations conducting trials should consider these issues in advance. The recommendations from this meeting should be helpful for all organizations involved in HIV vaccine trials, in particular for the national regulatory authorities in assessing the utility of phase IIB-TOC trials in the overall HIV vaccine research and development process.

Original languageEnglish (US)
Pages (from-to)539-546
Number of pages8
Issue number4
Publication statusPublished - Feb 2007



  • Clinical trial design
  • HIV vaccines
  • Phase IIB trials
  • Proof of concept trials
  • Test of concept trials
  • Vaccine efficacy

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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