US Congress to Consider Vaccine-Focused Legislation
Senator Richard Lugar and Congressman Pete Visclosky of Indiana, introduced companion bills in both houses of the US Congress calling for the enactment of a comprehensive strategy to accelerate the development, evaluation, and distribution of vaccines and other prevention technologies against diseases, including HIV/AIDS, tuberculosis, and malaria. This legislation is part of the "Vaccines for the Future Act of 2007" and calls for the US government to introduce new incentives that could increase the investment of the private sector in developing vaccines against diseases that primarily affect developing countries.
One recommendation specifically mentioned in these bills is the provision of US funding to support a pilot Advanced Market Commitment (AMC; see If you build it, they will pay, IAVI Report 9, 3, 2005) for a vaccine againstStreptococcus pneumoniae, the bacterium (also known as pneumococcus) that causes meningitis and pneumonia and is responsible for more than a million childhood deaths each year, according to the WHO. This AMC project was already endorsed by Italy, Canada, Norway, and the UK earlier this year. These countries pledged US$1.5 billion as part of a larger program, called the Advance Market Commitments for Vaccines Against Neglected Diseases, to promote industry involvement in developing vaccines that are most common in resource-poor nations. Currently two US-based pharmaceutical companies, Wyeth and Merck, have pneumococcal vaccines but it is unknown whether these current products would be appropriate for use in developing countries. If this model AMC proves successful at prodding industry into developing vaccines intended for developing countries, it could serve as the basis for similar agreements in the future related to HIV/AIDS, tuberculosis, or malaria.
The legislation also highlights, more generally, other areas where the government could help spur the development of effective vaccines through industry involvement, including endorsing improved regulatory procedures and providing support for intellectual property issues involved in the development of these life-saving interventions.
Canada Launches New HIV Vaccine Development Program
The Canadian government, with additional funding from the Bill & Melinda Gates Foundation, is establishing a research institute dedicated to the development of an effective AIDS vaccine. In February Prime Minister Stephen Harper announced his government's pledge of just over US$95 million to fund the new program, which is called the Canadian HIV Vaccine Initiative, and the Gates Foundation is also committing up to US$24 million to the project. The Foundation's contribution is another component of the Global HIV Vaccine Enterprise, which was established in 2003 as a way to further accelerate AIDS vaccine research and development.
The primary goals of the Canadian HIV Vaccine Initiative are to support Canadian scientists who are working on the scientific challenges of developing promising AIDS vaccine candidates, construct a new facility capable of manufacturing vaccine candidates for testing in clinical trials, and foster collaboration between researchers, both in Canada and internationally. Canada was one of the first countries to create a national AIDS vaccine plan and the government recently awarded IAVI a CAD$20 million to continue its work on the development of a safe and effective AIDS vaccine. "Canada has been a long-time supporter of AIDS vaccine research and has demonstrated laudable leadership in tackling the AIDS epidemic comprehensively, with a dual focus on both treatment and prevention," said Seth Berkley, CEO of IAVI.
Therapeutic Vaccine Trial Shows No Benefit
At the 14th annual Conference on Retroviruses and Opportunistic Infections (CROI), Brigitte Autran of the Hospital Pitié-Salpétriére in Paris presented results showing that therapeutic vaccination with the recombinant canarypox vaccine candidate vCP1452, developed by Sanofi Pasteur, offered no benefit to individuals interrupting treatment. Volunteers in this trial received either three or four injections (three primes and one boost) of the vaccine candidate encoding several HIV genes, including gp120, gag, pro, Nef, and RT, or placebo and were given the option to suspend their current highly-active antiretroviral therapy (HAART) regimen after the first dose of vaccine. Researchers then monitored these individuals closely and placed them back on therapy if their CD4+ T cells declined below 250 cells/ml of blood.
According to Autran the vaccine candidate showed significant immunogenicity in HIV-infected volunteers and provided modest clinical benefit, lowering the viral set point after treatment interruption, in previous studies. But at CROI she reported that in this latest study, MANON-02, all volunteers who received vCP1452 actually had to resume HAART sooner than those who received placebo (Abstract 126LB). Those who received four immunizations of the canarypox vaccine candidate actually had a five-fold increased risk of needing to resume treatment; 10 of 20 volunteers who received three immunizations had to resume therapy compared to14 of 19 in the four injection arm. Meanwhile only 3 of the 15 volunteers who received placebo had a decline in CD4+ T cell count that warranted resuming treatment.
Autran called these results "very disappointing" but said that she didn't think this trial should stop further study of this therapeutic vaccination approach. Researchers have long hoped that therapeutic vaccination would boost HIV-specific immune responses in HIV-infected individuals and therefore allow them to prolong the duration of treatment interruptions, without future therapeutic consequences. Treatment interruptions were first explored as a way to help individuals avoid some of the toxic and unpleasant side-effects of taking antiretrovirals (ARVs) and many different strategies have since been evaluated in clinical trials with mixed results.
The Sanofi-Pasteur vaccine candidate is also currently being tested in a preventive AIDS vaccine clinical trial, alone or in combination with a LIPO-5 vaccine, at HIV Vaccine Trials Network (HVTN) sites in the US. This trial is sponsored by the US National Institute of Allergy and Infectious Diseases and the Agence Nationale de Recherches sur le SIDA (ANRS). Several other trials with canarypox-based vaccine candidates are also ongoing. For more information about these or other preventive AIDS vaccine trials, visit the IAVI Report clinical trials database.
IAVI Report Awardees to Attend HIV Vaccine Symposium
This year IAVI is sponsoring IAVI Report Travel Award scholarships for four researchers from developing countries severely affected by HIV/AIDS to attend the upcoming Keystone Symposium: HIV vaccines from basic research to clinical trials, which is taking place in Whistler, Canada from March 25 to 30. This preeminent meeting on AIDS vaccine research is part of Keystone's Global Health Series and is supported with funding from the Bill & Melinda Gates Foundation. Keystone is trying to expand the involvement of developing-country researchers in this annual meeting, as well as other global health-focused symposia, and this year marks the first time that IAVI Report is providing travel awards. The goal of these awards it to provide scientists, physicians, post-graduate, or graduate students in resource-poor nations with the opportunity to attend important scientific meetings on AIDS vaccine research and development to broaden their understanding of the topic.
This year's awardees were selected by Keystone's scientific organizing committee and include Rugare Abigail Kangwende, who is an investigator at Africa University in Mutare, Zimbabwe. Kangwende is preparing to lead a team of investigators in a Phase I clinical trial, the first in the country. Gaudensia Nzembi Mutua, another travel-award recipient, is from the University of Nairobi in Kenya and is currently working on feasibility studies at a trial site that is now preparing for a Phase IIb test-of-concept AIDS vaccine trial that will be starting later this year. Ajay Wanchu is an HIV clinician at the largest clinic in the region, an immunologist, and a faculty member at the Postgraduate Institute of Medical Education and Research in Chanigarth, India. The final award-recipient, Louis Marie Yindom, is a PhD student at the Medical Research Council in Fajara, Gambia, who is studying the role of human leukocyte antigen (HLA) and killer immunoglobulin-like receptor in HIV-2 infection.
Vaccine Briefs written by Kristen Jill Kresge.