For patients with the heart failure condition transthyretin-mediated amyloidosis (ATTR) with cardiomyopathy, Alnylam’s Onpattro may not increase your chances of living longer or of avoiding a cardio event. But it can improve your quality of life.
The latter is what the company is emphasizing as it revealed results from the phase 3 Apollo-B study Thursday at the 18th International Symposium on Amyloidosis.
The trial of 360 patients showed that those on Onpattro were able to stave off the rapid decline in functionality that accompanies ATTR. In a 6-minute walk test, while those on Onpattro were able to walk 8.1 fewer meters after 12 months on the drug, those on placebo had a 21.3-meter decline, with the estimated median difference measuring 14.7 meters.
As the primary endpoint in the trial, the walk test makes the study a success, though the secondary endpoints may be more telling as they did not reach statistical significance. Those measured all-cause mortality and the frequency of all-cause hospitalizations and urgent heart failure visits.
Given the short duration of the study and the relatively small sample size, Alynlam didn’t expect to achieve the mortality endpoint, the company’s chief medical officer Pushkar Gurg said in a conference call, though he said he was “encouraged to see the mortality rates trended in favor of [Onpattro].”
“We believe that the benefits across so many endpoints and assessments were seen to merge as early as 12 months in a disease as complex as heart failure, speaks to the power of [Onpattro’s] undelying mechanism,” Gurg added. “Overall, we believe these results provide a suitable data package to support consideration for label expansion in the United States pending regulatory review.”
In a note to investors, analysts at Evercore ISI said they believe the results strengthen Alnylam’s bid to gain approval, also pointing to the positive trends in mortality and hospitalization, despite the failure to achieve statistical significance.
Based on the results, Stanford University cardiologist Kevin Alexander, M.D., told Evercore that he would likely use Onpattro alongside Pfizer’s market-leading Vyndaqel.
Onpattro is already sanctioned for hereditary ATTR-polyneuropathy, which affects peripheral nerves. But at 250,000, the ATTR-CM patient population is five times larger than that for hATTR-PM.
With an approval, Alynlam could take on Pfizer’s Vyndaqel and Vyndamax, which generated $909 million in sales in 2021, which was up 48% from 2020. Onpattro’s sales reached $475 million last year.
This could be a precursor for Alnylam in the indication as it tests another of its drugs, newly approved Amvuttra in a more extensive trial, the readout of which is scheduled for 2024.