NIH suspends enrolment in Remune study

Just weeks after the initiation of a phase III trial of Remune (HIV-1 Immunogen) in adult HIV-positive patients, the Adult AIDS Clinical Trials Group (AACTG), a multicenter cooperative funded by the National Institutes of Health’s Division of AIDS, has said that it will suspend enrollment while protocol changes are reviewed.

Following the start of the trial, data became available from a previous clinical endpoint study suggesting that it would be ‘very difficult’ to demonstrate through the current trial ‘that Remune would result in a 50% prolongation of time to virologic relapse, which was the point of the current study,’ ACTG Medical Officer Dr Elizabeth Adams told Reuters Health during a telephone interview.

The 96-week trial, known as A-5057, was designed to evaluate the safety and efficacy of The Immune Response Corporation’s intramuscular injection in increasing durability of viral suppression when administered in conjunction with patients’ existing antiretroviral regimens. ‘We can’t say one way or another whether Remune is effective or not effective, [but] we felt that this study was not going to have enough power’ to demonstrate a useful result, Adams stated.

The data that caused the investigators to reconsider the current study design was drawn from a virologic substudy of the data from the previous trial. One possibility is that the A-5057 protocol will be overhauled to focus on the vaccine’s immune effects, rather than on its antiviral actions, Adams noted.

The 131 participants who joined the study during its first few days will remain enrolled and will be observed using the revised protocol, but it is not yet obvious whether additional patients will be enrolled, even in a revamped version of the trial, Adams indicated. ‘Things are changing very rapidly,’ she said. ‘It’s not clear exactly what will happen.’ The trial had originally been expected to enroll 472 adult subjects. The Immune Response Company Vice President Creighton Lawhead stressed that the concern about the study is ‘absolutely not a safety issue.’ The ACTG had ‘gone out of its way’ in informing the company of the enrolment suspension to make it clear that Remune is a safe method of inducing helper T cell response in HIV-positive patients, he emphasized.

The current study is ‘one of many that are pivotal in nature’ for the vaccine, Lawhead said. A large, international study being conducted by Agouron, which holds marketing rights to the product, is ‘going well,’ he reported. ‘Agouron has publicly stated that they plan to file for approval in the US by the third quarter of next year, and they haven’t changed that,’ the executive added.

The Immune Response Corporation and Agouron highlighted previous studies suggesting that supplementing antiretroviral regimens with Remune injections every 3 months produces ‘improvements in markers of the immune response to HIV and positive trends in virologic markers.’