Moderna hits the gas as it begins dosing of 2nd HIV vaccine

Moderna announced Monday it's dosed the first patient in a trial testing its second mRNA HIV jab, less than six weeks after launching human trials for its first jab in January, a proverbial starting gun in the race for a breakthrough HIV therapy that’s now underway between Moderna and Excision BioTherapeutics. 

Moderna’s second HIV shot, mRNA-1574, takes a different approach to the first by targeting HIV envelope trimers via mRNA instead of eliciting broad antibodies against the virus. Its trial is another collaboration between the Cambridge-based biotech and the National Institutes of Health, this time partnering with the Division of AIDS within the National Institute of Allergy and Infectious Diseases. The trial is slated to test the candidate in 100 HIV-negative adults ages 55 and under. 

It follows the January launch of the company’s phase 1 trial for its other HIV jab, which tests sequential administration of HIV immunogens via mRNA as a way to elicit strong and durable B-cell responses. The company’s hypothesis, built upon research from William Schief, Ph.D., at Scripps University, is that B-cell response will over time develop into more broad and robust neutralizing antibodies. 

The dosing of its second trial is the latest development in the race for a new HIV therapy that now appears to be a two-horse race between Moderna and Excision BioTherapeutics, with the latter initiating its own nine-patient phase 1/2 trial at the end of January to test its CRISPR-based therapeutic that it boldly touts as a “functional cure” for the virus. 

Both Moderna's and Excision's therapies come as potential breakthrough alternatives to the standard course of care for HIV-positive patients, known as antiretroviral therapy, the first of which was approved more than 30 years ago. Antiretroviral treatments work by reducing the viral load of HIV to an undetectable level, thus making it impossible to spread. But such treatments must be taken daily and are ultimately not a cure. 

The phase 1 trials from both companies are not the only potential breakthroughs for HIV treatment. A day before they were launched in late January, new research indicated that popular PD-1 inhibitor cancer therapy Keytruda further wrestled HIV out of its dormant state in patients on antiretroviral therapy. The findings provided promise that future therapies could be both more effective and less frequent. 

As for Moderna, a timetime for top-line data for mRNA-1574 couldn't be found, but the primary completion date of the phase 1 trial for its other vaccine is slated for April 2023.