Cytokinetics Just Handed Bristol Myers Its Biggest Headache Yet

Perhaps most striking: the safety data showed serious adverse events occurred in only 5.6% of MYQORZO patients, compared to 9.3% on placebo. Read that again. The drug group had fewer serious problems than the group taking nothing. The new washout analysis (182 patients) also confirmed no cardiac blowback after stopping treatment.

The Camzyos Problem

Bristol Myers Squibb's Camzyos (mavacamten) got to market first, earning FDA approval in 2022. It pulled in $296 million in Q3 2025 alone and has approvals in more than 50 countries and regions. That's an incumbent with serious muscle (pun intended).

But incumbency doesn't mean invincibility.

Camzyos requires a strict monitoring program (called REMS) because of heart failure risk, with regular echocardiograms to check heart function. Both drugs carry black box warnings about reducing the heart's pumping strength, but MYQORZO's profile appears cleaner in trials. It showed faster biomarker improvements, with NT-proBNP (a heart stress marker) dropping 79% by week eight, reportedly quicker than mavacamten achieved in its pivotal studies.

Then there's the non-obstructive HCM angle. BMS tried to expand Camzyos into this broader patient population with its ODYSSEY-HCM trial and failed. Cytokinetics has its own shot at this market with ACACIA-HCM, with results expected around Q2 2026. If Cytokinetics wins where BMS lost, the competitive dynamics shift dramatically.

A Company With Something to Prove

MYQORZO is Cytokinetics' first-ever FDA-approved drug. The company got the green light on December 19, 2025, launched commercially on January 27, 2026, and has since secured approvals in China and the EU. Germany is next, with a planned launch in Q2 2026.

The backstory adds some spice. Cytokinetics and MyoKardia (the company that originally developed mavacamten) actually collaborated back in 2012. Then BMS swooped in and acquired MyoKardia for $13.1 billion in 2020, taking Camzyos with it. Cytokinetics kept developing its own candidate independently. This is essentially a rivalry born from a broken partnership.

Wall Street seems cautiously optimistic. Mizuho has a Buy rating at $100; Wells Fargo is at $95. The bulls are clearly betting that MYQORZO can carve out serious market share.

The Bigger Picture: A Duopoly Takes Shape

The HCM treatment market was worth about $573 million in 2025 and is projected to hit $683 million by 2030, though some estimates put the market significantly higher. That's not blockbuster-scale individually, but for a company like Cytokinetics going head-to-head against one of the world's largest pharma companies, the opportunity is substantial.

BMS is defending with a pediatric expansion (SCOUT-HCM showed positive results in January 2026), trying to lock in physician loyalty across age groups.

The real wildcard? Non-obstructive HCM represents the majority of all HCM cases. Swedish registry data shows nHCM accounts for about 67% of diagnoses. Whoever cracks that population opens a market several times larger than obstructive HCM alone. BMS already struck out. Cytokinetics is next at bat.

Why You Should Care

This isn't just a story about two heart drugs competing for prescriptions. It's a case study in how second-movers can win in biotech. Cytokinetics watched BMS go first, learned from its limitations (monitoring burden, failed expansion), and built a product designed to address those gaps.

The ACC data doesn't change everything overnight. But it gives doctors more confidence, gives patients more reason to ask about MYQORZO, and gives BMS more reason to worry. In a market where physician inertia is the biggest barrier to switching, every positive dataset is another crack in the dam.

Cytokinetics came to ACC with receipts. Now the question is whether the commercial machine can convert clinical wins into market share before BMS fortifies its defenses. The next six months will tell us a lot.