- Alnylam Pharmaceuticals said Thursday its experimental drug for hypertension met the main goal of a mid-stage clinical trial that evaluated multiple doses.
- According to Alnylam, three months after treatment, the two highest doses significantly reduced systolic blood pressure. The company said these reductions were sustained through six months of follow-up, which could support biannual dosing. The drug also showed “encouraging safety and tolerability,” according to Alnylam.
- A different mid-stage study is assessing the drug, called zilebesiran, in combination with one of three standard anti-hypertensive medications. Results are expected in early 2024. Some analysts believe that trial will be more important to the drug’s potential commercial opportunity.
Alnylam’s research revolves around so-called RNA interference technology, which effectively prevents cells from producing unwanted proteins. So far, the Massachusetts-based company has developed five approved medicines, most of which are for rare diseases. But with zilebesiran, Alnylam is going after a far more common condition that, by some estimates, affects nearly half of U.S. adults.
The topline results released Thursday didn’t disclose many specifics about how the drug performed in the trial. Alnylam said more details will be presented at an upcoming scientific conference.
On safety, however, the company did disclose that “serious adverse events” were reported in 3.6% of drug-treated patients and 6.7% of placebo-treated patients. Alnylam said none of these adverse events were considered to be related to zilebesiran, nor was one death in the drug arm that was caused by cardiopulmonary arrest.
"There are no major red flags in the topline with respect to safety, though we await more specifics,” wrote Paul Matteis, an analyst at the investment firm Stifel, in a note to clients.
Alnylam’s trial enrolled nearly 400 people whose hypertension was either untreated or stable through the use of one or more blood pressure medications. Participants who received 300 mg or 600 mg — the two highest regimens tested — experienced a placebo-adjusted blood pressure reduction of more than 15 mmHg.
Analysts are looking forward to a more detailed look at the study data, and, in particular, results from that other mid-stage study.
“KARDIA-2,” as the study is known, has enrolled about 675 participants whose hypertension isn’t adequately controlled with the current standard of care medications. The trial is adding Alnylam’s therapy onto one of three anti-hypertensive drugs — olmesartan, amlodipine and indapamide — to see if the combination is any better than those drugs paired with a placebo at reducing average daily systolic blood pressure.
Matteis wrote that the safety of zilebesiran when paired with other anti-hypertensive drugs “remains the key question” ahead of the KARDIA-2 results. He called that study “more important” for Alnylam’s program, a sentiment echoed by Leerink Partners analyst Mani Foroohar, who wrote in his own note clients that it’s “a more commercially relevant dataset.”
The Swiss pharmaceutical giant Roche sees a commercial opportunity in zilebesiran as well. In July, it agreed to pay Alnylam more than $300 million to share rights to the drug.
Roche also agreed to fund most of the costs for a large study meant to discover whether the drug can lower the risk of dangerous cardiovascular events like heart attacks and strokes.