New York, NY – A coalition of HIV/AIDS activists are calling for renewed attention to HIV-positive people termed immunologic non-responders (INRs), who experience sub-optimal immune system reconstitution despite years of viral load suppression by antiretroviral therapy.
Studies have shown that INR patients remain at increased risk of illness and death compared to HIV-positive people who have better restoration of immune function on current drug therapies. Risk factors for becoming an INR include older age and a low CD4 count at the time of treatment initiation. To date, efforts to develop immune enhancing interventions for this population have proven challenging, despite some candidates from small companies showing signs of promise.
“We believe there is an urgent need to find ways to encourage and accelerate development of therapies to reduce the health risks faced by INR patients,” stated Nelson Vergel of the Program for Wellness Restoration (PoWeR), who initiated the activist coalition. “For example, Orphan Drug designations[i] could be granted to encourage faster-track approval of promising therapies. These interventions may eventually help not only INRs but also people with other immune deficiency conditions”.
Along with funding, a major challenge for approval of any potential therapy is proving its efficacy. While INRs face significantly increased risk of serious morbidities and mortality compared to HIV-positive individuals with more robust immune reconstitution, demonstrating a reduction in the incidence of these outcomes would likely require expensive and lengthy clinical trials involving thousands of individuals.
Activists are therefore encouraging the US Food & Drug Administration (FDA), industry and researchers to evaluate potential surrogate markers of efficacy such as relative improvements in clinical problems that may be more frequent in INR patients, such as upper respiratory infections, gastrointestinal disease, and other health issues.
“Given the risks faced by INR patients, every effort should be made to assess whether less burdensome pathways toward approval are feasible, without compromising the regulatory requirement for compelling evidence of safety and efficacy”, said Richard Jefferys of the Treatment Action Group.
The coalition is advocating that scientists, biotech and pharmaceutical companies pursue therapeutic candidates for INRs. For example, while gene and anti-inflammatory therapies for HIV are being assessed in the context of cure research, there is also evidence that they may have potential to promote immune reconstitution and reduce markers associated with risk of morbidity and mortality in INR patients. Therapeutic research should also be accompanied by robust study of the etiology and mechanisms of suboptimal immune responses.
“While there is, appropriately, a major research focus on curing HIV, we must be alert to evidence that candidate therapies could have benefits for INR patients, and be willing to study them in this context”, argued Matt Sharp, a coalition member and INR who experienced enhanced immune reconstitution and improved health and quality of life after receiving an experimental gene therapy.
The coalition has held an initial conference call with FDA to discuss the issue. Minutes of that meeting are available online
[i] The purpose of the Orphan Drug Act is to incentivize the development of treatments for rare conditions. For more information, see: www.fda.gov/ForIndustry/DevelopingProductsforRareDiseasesConditions/ucm2005525.htm