A new blueprint for TB vaccines

13 Oct 2010

Babs Verblackt and Annmarie Leadman

Source: TropIKA.net

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Progress on the development of an updated ‘Blueprint for TB vaccines’ significantly advanced during the Second Global Forum on new TB vaccines held in Tallinn, Estonia, in September. The blueprint – to be developed over the next year – will guide the tuberculosis vaccine research community over the next decade. It will define the critical challenges for basic research, product development, manufacturing and clinical development, as well as laying the groundwork for rapid uptake and adoption of future new TB vaccines.

“The TB Vaccine Blueprint is designed to provide transformational ideas and innovative mechanisms that will result in safe, effective and affordable TB vaccines for the global community,” said Mike Brennan, Senior Advisor for Global Affairs at the Aeras Global TB Vaccine Foundation. Brennan chaired the Global Forum and plays a key coordinating role in the development of the revised TB vaccine plan.

Advances made over the past decade and challenges ahead were intensively discussed at the Forum (21–24 September 2010). More than 200 participants from 31 countries attended the meeting – ranging from scientists, clinicians and manufacturers to NGOs and governmental institutions active in the development of new vaccines against TB.

Since the First Global Forum on TB Vaccines in 2001 there have been a number of accomplishments. At that time no vaccines had yet advanced to human trials. Now ten TB vaccines are undergoing clinical trials. Trials of two further vaccines have been announced this year as well as a number of innovative new developments, including an assay development project to improve the assessment of vaccine efficacy.

“Having concrete vaccines in clinical trials is a big success for the field,” says Jelle Thole, director of the TuBerculosis Vaccine Initiative (TBVI), adding that the Forum had brought fruitful discussions and interesting thoughts. “We now have to make sure that these vaccines will become available to the people who need it by addressing the clinical challenges ahead.”

Progress in TB vaccine development

Updates on several vaccine candidates were given in presentations at the Forum, including MVA85A/AERAS-485, the currently most advanced vaccine candidate developed by Oxford University. Several TB vaccine candidates have shown promising early-stage results on safety and immunogenicity in studies conducted at well-established world-class TB vaccine research sites.

Researchers expect a new vaccine to be available by the end of the next decade. New vaccines will either boost or replace Bacille Calmette Guérin (BCG), initially developed in 1921 and presently the only available TB vaccine. BCG is protective against severe forms of TB in children, but not effective against pulmonary TB in adolescents and adults, globally the most common and form of TB.

The TB epidemic is growing more complex and difficult to control due to drug resistant forms of TB, including multi-drug resistant (MDR) and extensively drug-resistant (XDR) TB, and the deadly relationship between TB and HIV. TB is the leading cause of death among people living with HIV/AIDS. TB still causes nearly two million deaths a year.

An effective new vaccine will be a “game-changer”, both Christopher Dye of the World Health Organization (WHO) and Peter Small of the Bill & Melinda Gates Foundation underlined at the Forum. “An effective TB vaccine would fundamentally transform the strategy for global TB control and permanently change the trajectory of the epidemic,” said Small, the Foundation’s Senior Program Officer for TB.

Addressing challenges in the TB vaccine field

Besides celebrating accomplishments, the international meeting examined and reassessed the challenges in TB vaccine research and development. These vary from the scientific complexities of developing vaccines against a disease without predictive animal models and no known correlates of protection, to accurate development of timeline projections based on lessons learned, clinical trial design and financial support in an increasingly difficult fundraising environment.

The already long and complicated process of testing vaccines is made more challenging by a general lack of capacity for clinical trials worldwide. Several presenters discussed the need to expand significantly the number of clinical trial research sites in areas of high TB burden and the need to increase staff capacity, infrastructure and community awareness and support for clinical trials. Clinical researchers are also looking at alternative trial design modalities to accelerate clinical trial development timelines.

Progress and challenges were examined more deeply in workshops on basic research, applied research, manufacturing, regulation and vaccine access, clinical studies on TB vaccines, and partnerships, communication and advocacy. Participants had open, candid discussions on these issues, further detailing the experiences and feedback from the TB vaccine research community. The recommendations of these various working groups will be used for a new ‘Blueprint for TB vaccines’ that will be developed over the next year.

TB vaccine prioritization at the national level

Participants of the Forum agreed that more needs to be done to elevate TB on the world’s global health agenda, both in terms of attention and funding. The common sentiment that TB does not get the prioritization it needs was echoed by the preliminary results of a market research study, ‘Barriers and Drivers for Introduction of New TB Vaccines’, presented at the meeting. This study concludes that TB is considered a major public health issue by decision makers, yet commonly does not get the place of importance it needs as a health care priority.

The study, conducted in high-burden TB countries China, India, South-Africa, Brazil, Russia, Mozambique, Cambodia and Romania, consists of interviews with senior government health and finance officials, parliamentarians, NGO representatives and the media. It was done as part of a broader initiative of the Stop TB Partnership’s Task Force on Economics and Product Profiles for New TB Vaccines, which will be published online later this year.

For more on the 2nd Global Forum on TB Vaccines, including speaker presentations, please visit the conference website: www.tbvaccine2010.org.

Babs Verblackt is Associate Communications at the TuBerculosis Vaccine Initiative – TBVI.
Annmarie Leadman, is Director of Communications at the Aeras Global TB Vaccine Foundation.