HRS-1893

HRS-1893 is Hengrui/Suncadia's cardiac myosin inhibitor - same drug class as Bristol Myers Squibb's Camzyos (mavacamten) and Cytokinetics' Myqorzo (aficamten, FDA-approved January 2026) [10]. It's in Phase 2 for obstructive hypertrophic cardiomyopathy (NCT06516068) [1], with a second Phase 2 in heart failure with preserved ejection fraction opened in 2025 (NCT07269717) [2]. Chinese pharma fast-following a validated mechanism, several years behind the leaders, in a category with two approved drugs and growing commercial pull. The interesting question isn't whether the drug class works - that's settled. It's whether HRS-1893 can carve out enough differentiation on dosing, safety, or price to matter as a third mover into a market Camzyos and Myqorzo already share.

Novel compound, not approved anywhere. Phase 2 in obstructive HCM, with parallel Phase 1 work covering bioequivalence (NCT07479641), food effect (NCT07272330) [3], and renal impairment (NCT06775834) [4]. No public FDA designations - development is led primarily out of China by Shandong Suncadia, a Hengrui subsidiary. Hengrui's typical playbook is China-first registration with US filings following later, which matters for global timelines; no NMPA filing or ex-China licensing deal for HRS-1893 has been publicly announced as of mid-2026. The first published clinical data appeared in Br J Clin Pharmacol in 2026 - a Phase 1 healthy-volunteer PK/PD (pharmacokinetics - how the drug moves through the body - and pharmacodynamics - how it affects the heart) and food-effect study showing the molecule is orally bioavailable with predictable exposure [5]. The paper does not disclose a differentiated titration scheme versus mavacamten's echocardiogram-guided dosing, so any simpler-dosing differentiation thesis is unproven. No Phase 2 efficacy readout has been disclosed. Given Phase 2 enrollment is still ongoing in 2026, a meaningful efficacy readout in obstructive HCM is probably 2027 at the earliest, and a US filing - if Hengrui pursues one - is multiple years beyond that.

The heart's pumping power comes from myosin, a motor protein that pulls on actin filaments to contract muscle cells. In hypertrophic cardiomyopathy, mutations in beta-cardiac myosin (MYH7) make the heart muscle hypercontract - it squeezes too hard, the walls thicken, and in the obstructive form the thickened muscle physically blocks blood leaving the left ventricle. Open Targets gives MYH7 a 0.90 evidence score for HCM, about as strong as genetic validation gets. Cardiac myosin inhibitors slow down the motor: think of myosin as a piston firing too aggressively, and these drugs dial back the stroke. The mechanism is clinically and commercially validated. Mavacamten won FDA approval in 2022 (Camzyos, BMS) based on EXPLORER-HCM, which showed improved exercise capacity and a ~36 mmHg placebo-corrected reduction in post-exercise left ventricular outflow tract gradient [6]. Aficamten (Cytokinetics, now Myqorzo) was FDA-approved for obstructive HCM in January 2026 based on SEQUOIA-HCM, which reported a ~50 mmHg placebo-corrected reduction in post-Valsalva LVOT gradient, 49% of patients reaching gradient <30 mmHg vs 4% placebo, and a 7-point KCCQ symptom-score improvement [7][10]. So HRS-1893 isn't testing a hypothesis - it's testing a molecule against a target two competitors have already de-risked. The genetic case is strong, the pharmacology is reproducible across the class, and patient response is predictable from baseline LVOT gradient.

NCT06516068 is the Phase 2 in obstructive HCM and sits behind the headline of this writeup, but the available registry data does not include enrollment target, comparator arm, or the specific primary endpoint, so no description is fabricated here. What's typical for this class is LVOT gradient reduction at rest and post-Valsalva (a breath-holding maneuver that stresses the heart and unmasks dynamic obstruction) at 12-24 weeks, with NYHA functional class and exercise capacity as secondary endpoints - that's what EXPLORER-HCM and SEQUOIA-HCM used. The HFpEF trial (NCT07269717) is more concretely described: Phase 2, recruiting 48 patients, primary endpoint is incidence and severity of adverse events [2]. That's a small, safety-focused signal-seeking study, not a registration trial. A safety-only primary at n=48 means any HFpEF efficacy data will be exploratory. The HFpEF expansion is strategically interesting - aficamten is also being tested in HFpEF (CEDAR-HF) and the indication is far larger than HCM, but the biological case is weaker because HFpEF isn't driven by myosin hypercontractility in the same way. Read the HFpEF program as optionality, not the core thesis.

Our model gives this drug a 15% chance of eventually being approved. That starts from the historical approval rate for Phase 2 drugs in this area, which is about 27%, then adjusts based on ten specific facts about the trial and sponsor. The estimate goes up because the trial uses a non-randomized design and has more secondary endpoints than usual, but goes down because the sponsor has a thin or weak approval record and earlier-phase results were weak or limited. Most other factors were close to average for this stage, so they didn't move the estimate much from where it started.

Four concrete failure modes. First, on-target safety. Cardiac myosin inhibitors reduce contractility by design - push too hard and you cause systolic dysfunction. Camzyos carries a boxed warning for heart failure and requires a REMS program (Risk Evaluation and Mitigation Strategy - a mandatory FDA-imposed safety monitoring program that requires serial echocardiograms before refills and restricts prescribing) [8]. HRS-1893 will need to land in the same therapeutic window with a comparable or wider safety margin to justify switching. Second, regulatory geography. Hengrui's China-first strategy means a positive Phase 2 doesn't automatically translate into a near-term US filing. Bridging Chinese trial data to FDA standards adds years and execution risk, and Chinese sponsors have had mixed reception at FDA cardiology divisions. Third, commercial timing and differentiation. Camzyos did roughly $611M in 2024 revenue and is growing, but uptake has been slowed by REMS friction and cardiology adoption curves [9]. Myqorzo (aficamten), now approved, is positioned to take share on a cleaner dosing profile. HRS-1893 entering the global market in the early 2030s as a third mover needs a clear differentiation story - better safety window, oral once-daily without echo-guided titration, lower price - and none of that has been publicly demonstrated yet. Fourth, exclusivity timing. Camzyos has US orphan-drug exclusivity through ~2029 (7 years from 2022 approval) and composition-of-matter patents extending toward ~2033, with the earliest realistic generic entry estimated around 2036 [11]. That means HRS-1893's most likely commercial window opens against branded incumbents, not a price-eroded generic landscape - which raises the bar for switching economics rather than lowering it.

Worth watching, not yet a signal. The mechanism is real, the sponsor is credible (Jiangsu Hengrui is one of China's top pharma companies), and HCM is a growing market with the strongest genetic validation in cardiology. But the public data so far is Phase 1 PK and a Phase 2 that hasn't read out, and the competitive landscape just got harder - Myqorzo (aficamten) approved January 2026 means HRS-1893 is now chasing two approved drugs, not one. The specific trigger to upgrade this from background to active interest: Phase 2 efficacy data from NCT06516068 showing LVOT gradient reduction comparable to mavacamten (~36 mmHg placebo-corrected) or aficamten (~50 mmHg placebo-corrected) with either a cleaner safety profile, simpler titration (no echo-guided dose adjustment), or a meaningful price/access angle for ex-US markets. Without one of those, this is a me-too chasing two approved competitors into a market they already share, with branded patent protection running through the early 2030s. Check back when Hengrui or Suncadia announces top-line Phase 2 data - probable window is 2027. Secondary signal: if Hengrui announces an NMPA filing, a US/EU bridging trial, or a global development partner, that's a real escalation of intent and timeline.