{"id":2751,"date":"2026-08-28T08:00:00","date_gmt":"2026-08-28T12:00:00","guid":{"rendered":"https:\/\/www.insilens.com\/?p=2751"},"modified":"2026-08-28T16:38:09","modified_gmt":"2026-08-28T20:38:09","slug":"aficamten-succeeds-in-phase-iii-non-obstructive-hcm-trial","status":"publish","type":"post","link":"https:\/\/www.insilens.com\/?p=2751","title":{"rendered":"Aficamten Succeeds in Phase III Non-Obstructive HCM Trial"},"content":{"rendered":"

Company:<\/strong> Cytokinetics · Drug:<\/strong> Aficamten (MYQORZO) · Trial:<\/strong> ACACIA-HCM (Phase III) · Indication:<\/strong> Non-Obstructive Hypertrophic Cardiomyopathy · Date:<\/strong> August 28, 2026<\/p>\n

\"20260828_Cytokinetics_Aficamten_Therapeutic_Indications\"<\/p>\n

Summary<\/h4>\n

Cytokinetics’ ACACIA-HCM trial met both co-primary endpoints for aficamten, marketed as MYQORZO for obstructive hypertrophic cardiomyopathy, in patients with non-obstructive hypertrophic cardiomyopathy, positioning the company to pursue a supplemental filing that would extend the drug’s approved indication.<\/p>\n

What Happened<\/h4>\n

The 517-patient trial met both co-primary endpoints: KCCQ score improved by 3.0 points adjusted versus placebo (p=0.021), and peak VO2 improved by 0.67 mL\/kg\/min adjusted versus placebo (p=0.003). Serious adverse events occurred in 20.2% of aficamten patients versus 14.7% on placebo, and left ventricular ejection fraction below 50% occurred in 10.5% of aficamten patients versus 0.8% on placebo. A cardiovascular event-time composite secondary endpoint was not statistically significant. Cytokinetics plans to submit a supplemental new drug application in the fourth quarter of 2026.<\/p>\n

Deep Analysis<\/h4>\n

The effect sizes on both primary endpoints are statistically significant but modest in absolute terms, small differences in symptom score and exercise capacity, which raises questions about clinical meaningfulness at the individual-patient level even though the trial crossed its pre-specified significance thresholds. The safety data are the more consequential finding: a meaningfully higher rate of reduced ejection fraction, more than tenfold versus placebo, alongside a higher serious adverse event rate, reinforces the known cardiac-depression risk of myosin inhibitors and will likely require continued monitoring protocols. The non-significant cardiovascular event-time endpoint, presumably included to capture harder outcomes beyond symptom and exercise measures, tempers a reading of this as an unambiguous win.<\/p>\n

Company and Product Background<\/h4>\n

Cytokinetics’ aficamten is a cardiac myosin inhibitor already approved as MYQORZO for obstructive hypertrophic cardiomyopathy. Non-obstructive HCM represents a larger, previously underserved patient population without an approved targeted pharmacologic option.<\/p>\n

Signal Extraction<\/h4>\n\n\n\n\n\n\n\n
Factor<\/th>\nAssessment<\/th>\n<\/tr>\n
Trial<\/td>\nACACIA-HCM, 517 patients, Phase III<\/td>\n<\/tr>\n
Primary Endpoints<\/td>\nKCCQ +3.0 pts (p=0.021); peak VO2 +0.67 mL\/kg\/min (p=0.003), both met<\/td>\n<\/tr>\n
Safety<\/td>\nSerious AEs 20.2% vs 14.7%; LVEF below 50% in 10.5% vs 0.8%<\/td>\n<\/tr>\n
Secondary<\/td>\nCardiovascular event-time composite not statistically significant<\/td>\n<\/tr>\n
Regulatory Path<\/td>\nsNDA planned Q4 2026, building on existing MYQORZO approval<\/td>\n<\/tr>\n<\/table>\n

Reading the Signal<\/h4>\n

Bull case:<\/strong> Meeting both co-primary endpoints in a placebo-controlled Phase III trial gives Cytokinetics a viable regulatory path to expand MYQORZO into the larger non-obstructive HCM population, an indication that currently has no approved targeted therapy.<\/p>\n

Bear case:<\/strong> The effect sizes are modest, the harder cardiovascular event-time endpoint missed significance, and the more than tenfold increase in reduced ejection fraction versus placebo underscores a real safety trade-off that regulators and prescribers will need to weigh against the symptomatic benefit.<\/p>\n

InSilens Take<\/h4>\n

This is a regulatory-enabling win rather than an unambiguous clinical triumph, the efficacy margins are thin and the ejection-fraction safety signal is the number that will most shape how FDA and cardiologists approach labeling and monitoring for a non-obstructive HCM indication.<\/p>\n

Signal Assessment<\/h4>\n

Importance:<\/strong> 5\/5 · Direction:<\/strong> Positive · Confidence:<\/strong> High on facts, Moderate on interpretation<\/p>\n","protected":false},"excerpt":{"rendered":"

Cytokinetics’ ACACIA-HCM trial met both co-primary endpoints for aficamten, marketed as MYQORZO for obstructive hypertrophic cardiomyopathy, in patients with non-obstructive hypertrophic cardiomyopathy, positioning the company to pursue a supplemental filing that would extend the…<\/p>\n","protected":false},"author":1,"featured_media":2762,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11,3],"tags":[458,459],"class_list":["post-2751","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-clinical","category-therapeutic-indication","tag-aficamten","tag-hypertrophic-cardiomyopathy"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2751","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2751"}],"version-history":[{"count":1,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2751\/revisions"}],"predecessor-version":[{"id":2771,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2751\/revisions\/2771"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/media\/2762"}],"wp:attachment":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2751"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2751"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2751"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}