Cytokinetics shows hand in high stakes rivalry with BMS' Camzyos

Cytokinetics has set out to prove that aficamten is a threat to Bristol Myers Squibb’s $13.1 billion heart disease drug Camzyos, and a new analysis gives the first shot at an apples-to-apples comparison with late-phase data showing improvements in exercise capacity among patients. 

Having reported primary endpoint success in December 2023, the biotech rolled into the European Society of Cardiology Heart Failure 2024 Congress on Monday armed with a broad slate of phase 3 data from the SEQUOIA-HCM trial on the asset. The top-line readout showed the cardiac myosin inhibitor aficamten is better than placebo at improving the exercise capacity of patients with obstructive hypertrophic cardiomyopathy.

But the data drop left a slew of questions unanswered, particularly with regards to how the molecule squares up to approved rival Camzyos. The event marks the first time the biotech has shared data from an exploratory analysis that allows a more direct comparison between aficamten and Camzyos.

While Cytokinetics’ primary endpoint in the SEQUOIA-HCM trial just looked at exercise capacity, Camzyos was tested on a composite measure that assessed exercise capacity and symptoms in the registrational study that underpinned the therapy's FDA approval. Cytokinetics' exploratory analysis shows how aficamten fared on the primary endpoint used to back up Camzyos.

Forty-two percent of people on aficamten met the composite exercise capacity and symptom endpoint, compared to 14% of their counterparts on placebo. In the Camzyos trial, 37% of patients on the study drug met (PDF) the response criteria, versus 17% on the placebo. The placebo-adjusted difference is bigger in the aficamten trial, 28%, than the Camzyos study, 19%.

Cytokinetics is also using the event to share results from pre-specified analyses of dosing and safety, including the incidence and consequences of left ventricular ejection fraction (LVEF) falling below 50%. A LVEF of 50% to 70% indicates the normal pumping of blood from the heart’s left lower chamber. 

While 3.5% of patients on aficamten had a LVEF of less than 50%, as determined by the core laboratory, there were no instances of worsening heart failure or treatment interruptions due to low LVEF. Six percent of patients on Camzyos had LVEF of under 50%. LVEF returned to above the normal threshold after treatment with Camzyos was interrupted.

Investors sent Cytokinetics’ share price skyward when they saw the top-line data in December 2023 and kept the momentum going as reports of a Big Pharma buyout swirled. The chatter and the biotech’s share price have cooled since then, with the stock steady in premarket trading around $62 Monday morning.

The congress gives Cytokinetics a chance to show cardiologists are excited about the drug candidate ahead of its filing for FDA approval in the third quarter.