NEW YORK (GenomeWeb News) – Alnylam Pharmaceuticals has obtained human proof-of-concept results for its anti-viral RNAi therapeutic, ALN-RSV01, the company announced today.
The RNAi human therapeutic results — reportedly the first in the industry — came from the GEMINI study, a Phase II, randomized, double-blind infection study comparing ALN-RSV01 to placebo. The study suggests ALN-RSV01 significantly decreases the infection rate of respiratory syncytial virus. Alnylam scientists are expected to present details of the GEMINI study this weekend at the International Symposium on Respiratory Viral Infections in Singapore.
“As you can imagine, we’re very pleased with the outcome of the GEMINI study,” Akshay Vaishnaw, Alnylam’s vice president of clinical research, said in a conference call with reporters. “The data demonstrated a clear antiviral effect, as evidence by statistically significant reduction in RSV infection rate, which was the primary efficacy outcome, and consistent improvements across a range of other viral measures.”
During the study, the researchers enrolled 88 subjects and infected them with a wild type, clinical strain RSV. During the 12 days that they were quarantined, these subjects received five days of intranasal treatment either with ALN-RSV01 or with placebo — two days before infection and three days after infection.
Researchers measured the infection rates in the subjects using several different assays, including a plaque assay and RT-qPCR. Based on the plaque assay, the researchers reported a 38.1 percent reduction in infection rate with ALN-RSV01 compared to placebo. RT-qPCR results indicated a more modest decrease in infection rate, though Vaishnaw noted, that test detects both active virus and viral fragments that are not as clinically relevant.
“While we are very pleased with these findings, we’re also very pleased with the sheer consistency of the results across these several different assay systems — the plaque assay, the RT-PCR, the spin-enhanced culture, and the RSV antigen assay,” Vaishnaw said. “We believe this speaks to the robustness of the data.”
The researchers did not detect a significant difference in clinical symptoms among the 88-subject group, but the treatment was apparently safe and well tolerated. Company officials said they would to test the therapy in a larger group to get a better idea of the difference in symptoms.
“We have a molecule that demonstrates significant anti-viral efficacy in man, and we see that fact as a very important de-risking even for RNAi therapeutics in general and for the RSV program in particular,” Barry Greene, Alnylam’s president and COO, said in the conference call. “This is an incredible step in creating an entire new class of drugs — RNAi therapeutics.”
Even so, company representatives noted that there are limitations in this sort of infection studies compared to studying naturally infected patients. A Phase II study of naturally infected adult subjects is anticipated in the first half of this year. The details of that study are expected to be released shortly.