Crucell's shares have taken a hit since last Friday, when the news that Phase I and II trials of Merck's investigational HIV vaccine (produced using Crucell's technology) were being discontinued after the treatment failed to prevent HIV infection in trial subjects. Crucell issued a statement yesterday saying that, disappointing as the news regarding Merck's investigational vaccine was, it does not appear to have had anything to do with the efficacy or safety of the PER.C6 technology. The company is attempting to quell fears regarding the impact the news could have on its prospects, and has confidently reiterated its guidance for this year, maintaining expectations that total revenue and other operation income for 2007 will be in the €220m to €225m range. "We had not incorporated any income from the Merck HIV program in our guidance for 2007," the company said. "As the program was in a Phase II study it was not at all expected to enter the market within the next couple of years to generate royalty-based income for Crucell." The company would presumably have received milestone and royalty payments if the Merck vaccine had proved effective, but a company spokesperson was not willing to disclose any information regarding the impact of the vaccine failure on longer-term financial estimates. The potential HIV jab was a trivalent vaccine that used an adenovirus vector to transport three synthetically produced HIV genes into patients' cells. The delivery of these genes was hoped to stimulate a potent cellular immune response to HIV, resulting in an army of destructive T cells that would rid the body of HIV-infected cells. Merck abandoned the vaccine trials after a review by the Data Safety and Monitoring Board (DSMB) highlighted that the jab failed to meet its endpoint, with results showing very little difference in the incidence of HIV infection between subjects given placebo and those injected with the real vaccine. Merck has been working on its HIV programme for the last two decades, with much hope pinned on the V520 vaccine candidate that ultimately proved such a disappointment last week. Early studies in monkeys and later proof of concept trials in human subjects had suggested that the vaccine generated a "strong and durable immune response" against HIV. However, full scale trials failed to bear out these early findings, proving a "huge disappointment" for the HIV Vaccine Trials Network (HVTN) who co-sponsored Merck's vaccine efforts, as well as the wider HIV community. Merck and Crucell have a long-standing relationship, one that was expanded only two weeks ago as Crucell granted the firm access to the PER.C6 technology for use in two additional disease areas. Crucell announced Merck's intention to apply the cell line technology to its HIV vaccine project back in 2001, part of an agreement that was seen as particularly significant as it marked Crucell's very first exclusive license with a leading vaccine company. Although this particular HIV project has now fallen by the wayside, the data generated by the studies will be used to help provide insight and inform future activities aimed at identifying an HIV vaccine, said Merck and HVTN. According to a Crucell spokesperson, the relationship between the two companies remains strong, and Merck is continuing other projects making use of the PER.C6 technology for other development projects.