GenePro has been evaluated in preclinical models. In one of the most striking trials, 12 macaque monkeys received two intramuscular injections of the vaccine before challenged with the highly pathogenic SHIV 89.6P virus.
All 12 of the vaccinated macaques showed a rapid reduction in peak viral loads, and their CD4+ counts remained high. (Low CD4+ cell counts are a biomarker for disease progression.) All 12 macaques lived for two or more years, and the viral loads became undetectable over time.
In contrast, seven control macaques not pretreated with GenePro showed high viral loads and significant loss of CD4+ cells after exposure to the SHIV 89.6P virus. Four of the controls developed AIDS and died, and two more were at high risk for AIDS after two years.
Based on preclinical work, Laufenberg predicts that GenePro may work best in patients in the early stages of HIV who have low levels of HIV and high CD4+ counts. Once the immune system gears up to fight HIV, the DNA vaccine should limit viral replication and prevent progression to AIDS. A reduced dependency on HAART should follow.
Although the incidence and prevalence of AIDS is down sharply since the introduction of HAART, the complex drug regimen is expensive, inconvenient, and has substantial side effects. Preclinical trials suggest that GenePro may prevent the spread of HIV, too. “GenePro could especially benefit the 2.5 million children in the world with HIV to help them live healthier lives,” Laufenberg says.
Superior preclinical results are not the only factors working in GenePro’s favor. DNA vaccines, in genera, hold a number of advantages over competing recombinant protein and viral vector vaccines. DNA vaccines are easier and less expensive to make than recombinant protein or viral vector types.
Recombinant protein vaccines are typically cleared relatively quickly and do not trigger a strong enough cellular immune response to control HIV. Viral vector vaccines induce an immune response to both the non-HIV vector and HIV components, and the response to the vector may limit the response to the target antigens. Moreover, most protein and viral vector vaccines require refrigerated storage, whereas DNA vaccines can be stored at room temperature. This will make it easier to treat people infected with HIV worldwide with GenePro.
Laufenberg plans to hold a pre-IND meeting with the FDA by the end of the year. Currently, he is the company’s sole full-time employee and keeps costs down by contracting out technical services. Once Phase I trials start, the company will scale up to 12 full-time positions. When the efficacy of GenePro is proven, ImmunoGenetix will seek partners at larger pharmaceutical and biotechnology companies to advance its development.
“The promise is phenomenal,” says Laufenberg. “We can treat HIV, keep viral loads down and CD4+ counts high, and there’s less toxicity and less chance for drug resistance.”