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When Cytokinetics received FDA approval for aficamten in December 2025, the milestone closed one of the longest commercial droughts in modern biotechnology. Founded in 1998, the company spent 27 years advancing ambitious clinical programs that repeatedly failed to translate into approvable medicines.
Those failures were anything but random and followed a consistent pattern. One shaped by strategic resets, optimism bias in clinical interpretation, and an enduring belief that muscle contractility could be pharmacologically engineered into disease-modifying therapies.
Aficamten ended that drought, but it did not erase the cost of what came before.
The lost decade: Oncology and the first strategic reset (1998–2008)
Cytokinetics was founded in 1998 by leaders in muscle and cytoskeletal biology, with a platform vision that extended well beyond cardiology. Early research programs targeted oncology and antifungal indications and were built around the cytoskeleton as a therapeutic entry point. Among the most advanced assets was ispinesib, a kinesin spindle protein (KSP) inhibitor positioned as a novel anti-mitotic cancer therapy.
The strategy failed to produce commercial traction. Despite going public in 2004, the company entered its second decade without a viable late-stage oncology asset. In 2008, Cytokinetics executed what it described as a “strategic realignment,” discontinuing oncology and antifungal research entirely. Collaborative oncology agreements, including partnerships with GlaxoSmithKline, were terminated.
A full decade of pipeline development was written off, and Cytokinetics reset its identity around a single hypothesis: that precisely modulating muscle contractility could produce clinically meaningful outcomes. From that point forward, every major program would live or die by that assumption.
ALS and the collapse of the neuromuscular franchise (2009–2023)
Amyotrophic lateral sclerosis became the first major test of that hypothesis. Cytokinetics spent more than a decade attempting to treat ALS with fast skeletal muscle activators, advancing two successive late-stage programs that ultimately failed.
The first, tirasemtiv, was positioned as a cornerstone asset. In 2017, results from the Phase 3 VITALITY-ALS trial were released. The outcome was unequivocal. Tirasemtiv failed to meet its primary endpoint of slow vital capacity and showed no benefit across secondary endpoints. Development was suspended immediately.
Rather than exit ALS, Cytokinetics pivoted to reldesemtiv, a next-generation compound designed to improve tolerability and potency. Early warning signs emerged in 2019, when the Phase 2 FORTITUDE-ALS trial failed its primary endpoint, with a p-value of 0.11. Despite the lack of statistical significance, the company advanced reldesemtiv into Phase 3 based on post-hoc analyses suggesting potential functional benefit.
That bet failed. In 2023, the Phase 3 COURAGE-ALS trial was terminated early following a Data Monitoring Committee review. The partnership with Astellas was dissolved, and the reldesemtiv program was terminated. With it, Cytokinetics exited neuromuscular disease after nearly 15 years of investment.
The ALS experience crystallised a recurring pattern: late-stage escalation driven by secondary signals rather than clear Phase 2 wins, followed by decisive failure at scale.
Omecamtiv Mecarbil: Sixteen years of persistence (2006–2023)
If ALS defined the company’s neuromuscular ambitions, omecamtiv mecarbil defined its endurance. Developed in collaboration with Amgen starting in 2006, omecamtiv was a cardiac myosin activator intended to improve systolic function in heart failure.
Clinical concerns surfaced early. In 2013, the Phase 2 ATOMIC-AHF trial failed its primary endpoint of improving dyspnoea, with a p-value of 0.33. Statistically, the result offered no evidence of efficacy. Nonetheless, Cytokinetics and Amgen advanced the drug into Phase 3, citing favorable secondary trends.
The pivotal GALACTIC-HF trial, enrolling more than 8,000 patients, reported in 2020. While the study technically met its primary composite endpoint, the effect size was modest, an 8% relative risk reduction, and the trial failed to demonstrate a benefit on cardiovascular death. Shortly after, Amgen terminated the collaboration, returning the rights to Cytokinetics.
Rather than abandon the asset, Cytokinetics pressed on. In 2022, the METEORIC-HF trial, designed to assess exercise capacity, failed outright, showing no benefit over placebo. In February 2023, the FDA issued a Complete Response Letter, concluding that the GALACTIC-HF data were “not sufficiently persuasive” to establish effectiveness and requesting an additional clinical trial.
By that point, omecamtiv had consumed nearly two decades of development time. Yet even after regulatory rejection, Cytokinetics initiated another Phase 3 confirmatory study, COMET-HF, in late 2024, extending their investment in a program that had already failed multiple efficacy tests.
Aficamten: Scientific vindication, operational friction (2024–2025)
Cytokinetics’ first success arrived through muscular inhibition. Aficamten, commercialised as Myqorzo, is a cardiac myosin inhibitor for obstructive hypertrophic cardiomyopathy. Mechanistically, it reversed the company’s prior approach, reducing excessive contractility rather than amplifying it.
The clinical data held up to scrutiny, and in December 2025 the FDA approved aficamten, ending the company’s 27-year wait for a commercial product. The approval, however, was not without friction. Earlier in 2025, the FDA delayed its decision after Cytokinetics submitted the NDA without a Risk Evaluation and Mitigation Strategy (REMS).
Given that Camzyos, a direct competitor, was already subject to a REMS due to heart-failure risk, the omission raised eyebrows. The FDA classified the late REMS submission as a Major Amendment, extending the review timeline and pushing approval to the final weeks of the year.
The episode underscored a broader theme: scientific maturity had not been matched by commercial or regulatory fluency.
What the record reveals
Cytokinetics’ history is not one of scientific incompetence. Its work on sarcomere biology is widely respected, and aficamten ultimately validated the underlying mechanism. The failures instead reflect structural and cultural tendencies.
First, optimism bias shaped clinical decision-making. Both reldesemtiv and omecamtiv advanced into Phase 3 after failing primary Phase 2 endpoints, relying on post-hoc trends that did not hold up at scale.
Second, persistence carried an extraordinary opportunity cost. Omecamtiv alone tied up capital and organisational focus for nearly 20 years.
Third, the transition from R&D to commercial execution proved non-trivial. The REMS delay highlighted the challenges faced by a company launching its first product after decades as a development-stage entity.
The financial toll is explicit. As of December 31, 2023, Cytokinetics reported an accumulated deficit of approximately $2.1 billion, quantifying the cost of the longest drought in its history.
Aficamten ended that drought. But the story of Cytokinetics is ultimately a reminder that, in biotechnology, the path to success is littered with failure.
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