HRS-1893

HRS-1893 is Jiangsu Hengrui Pharmaceuticals' cardiac myosin inhibitor, in Phase 2 for obstructive hypertrophic cardiomyopathy (HCM), a disease where the heart muscle grows abnormally thick and blocks blood flow. The program follows the same mechanism as Bristol Myers Squibb's mavacamten (Camzyos) and Cytokinetics' aficamten (Myqorzo), both now FDA-approved and proving the class works [8][10][13]. Development sits inside Shandong Suncadia Medicine, a Hengrui subsidiary, with the primary Phase 2 recruiting under NCT06516068 alongside a 300-patient long-term safety Phase 2 (NCT07021963) and a separate Phase 2 exploring heart failure with preserved ejection fraction (NCT07269717) [5][6][14]. The mechanism works. The real question is whether a China-originated third entrant can carve out share against two Western drugs. Camzyos generated roughly $600M in 2024 per BMS's annual report, and Myqorzo only launched in the US in early 2026, so cardiologist familiarity outside the mavacamten franchise is still forming [11][13]. First-in-human PK, safety, and food-effect data were published in British Journal of Clinical Pharmacology in early 2026, so the compound has cleared basic drug-ability [1]. What comes next is proof it can move the pressure gradient across the left ventricular outflow tract on par with the incumbents. HRS-1893 is delivered as an oral tablet [3]; a specific once-daily versus twice-daily regimen has not been publicly disclosed.

HRS-1893 is a novel small molecule, never approved anywhere. Phase 1 first-in-human dosing, food-effect, and bioavailability work is complete or wrapping up, with results published in BJCP in early 2026 [1]. The BJCP paper reports PK, safety, and food effect in healthy volunteers; it does not disclose pharmacodynamic readouts on contractility or LVEF, which is standard for this class since healthy volunteers lack the hypercontractile substrate to show a meaningful signal. Additional Phase 1 records exist for a completed food-effect study (NCT07272330), a bioequivalence study of two tablet formulations (NCT07479641), and an early single-ascending-dose study in Australia (NCT07033455) [2][3][4]. Two Phase 2 trials in HCM are actively recruiting: the obstructive HCM efficacy trial (NCT06516068) and a 300-patient long-term safety trial (NCT07021963) [5][14]. A separate Phase 2 in heart failure with preserved ejection fraction (HFpEF), NCT07269717, is also recruiting, hinting that Hengrui wants to run the same expansion play Cytokinetics is running with aficamten [6]. There are no publicly disclosed FDA designations: no breakthrough, no fast track, no orphan status. That is consistent with a compound developed China-first, where the initial regulatory path runs through the National Medical Products Administration (NMPA) rather than the FDA. On the China side, no NMPA breakthrough or priority review designation has been publicly announced for HRS-1893 as of August 2026, and no domestic filing has been signaled. Chinese cardiovascular drugs originating in domestic Phase 2 typically take three to five years to reach NMPA approval, so a Chinese approval before 2028 would be aggressive. Expected timeline: with Phase 2 recruitment still open, top-line data on the obstructive HCM cohort is unlikely before late 2026 or 2027, and Phase 3 initiation for a US or European filing has not been announced. The bioequivalence study of two tablet formulations is a quiet tell that commercial formulation work is underway, an activity typically preceding Phase 3 [3].

Cardiac muscle contracts because a motor protein called myosin grabs actin filaments and pulls, over and over, powered by ATP. In hypertrophic cardiomyopathy, mutations in the MYH7 gene (which codes for the heavy chain of cardiac myosin) leave the motor stuck in a hyperactive state. The muscle contracts too forcefully and does not relax properly. Over time the heart wall thickens, and in the obstructive form of HCM, the thickened septum crowds the outflow tract, choking blood leaving the ventricle [7]. Patients feel it as chest pain, shortness of breath, and syncope, and the risk of sudden death is real. A cardiac myosin inhibitor binds the motor and dials down the number of myosin heads engaging actin at any moment. Contractility drops toward normal, relaxation improves, and the outflow gradient falls. The genetic case is airtight: MYH7 mutations directly cause the disease, with an Open Targets evidence score of 0.89 for HCM. The pharmacological case is also settled. Mavacamten (BMS's Camzyos) won FDA approval in April 2022 based on EXPLORER-HCM, which showed clinically meaningful improvement in symptoms and outflow gradient [8][9]. Aficamten (Cytokinetics' Myqorzo) received FDA approval on December 19, 2025 based on the Phase 3 SEQUOIA-HCM trial [10][13]. In cross-trial comparisons, which are unreliable due to differences in patient selection, titration protocols, and monitoring cadences, aficamten appeared to show less LVEF suppression than mavacamten; no head-to-head data exist. The biology is not the question for HRS-1893. Whether Hengrui's specific molecule matches that efficacy without the tolerability issues that dogged the first-generation compound is.

The obstructive HCM Phase 2 (NCT06516068) is the primary asset [14]. Public registration is thin on specifics, and the study protocol has not appeared in a peer-reviewed venue. Companion trials give useful context. The long-term safety Phase 2 (NCT07021963) enrolls 300 HCM patients and tracks adverse event incidence and severity, an unusually large safety database for a Phase 2 and a signal Hengrui is preparing infrastructure for a Phase 3 pivot [5]. The HFpEF Phase 2 (NCT07269717) enrolls 48 patients with adverse events as the primary endpoint, which is a Phase 1b/2a-style safety readout rather than an efficacy trial [6]. The Phase 1 bioequivalence study of two tablet formulations (NCT07479641, n=58) suggests the program is finalizing commercial formulation [3]. What is missing from the public record: specific efficacy endpoints in the obstructive HCM trial, whether a comparator arm is included, and details on genotype-based patient selection. Mavacamten and aficamten both used the Valsalva-provoked left ventricular outflow tract (LVOT) gradient (the outflow obstruction measured during a forced breath-hold maneuver that exaggerates obstruction, the standard stress test in HCM) and the KCCQ (Kansas City Cardiomyopathy Questionnaire, a validated patient-reported symptom score) as primary or key secondary endpoints [9][10]. If HRS-1893 does not use comparable endpoints, direct cross-trial comparison, the only credible path to a differentiation claim, becomes very difficult. That is a real concern for a compound that will need to compete against approved drugs on either efficacy magnitude or safety profile.

Our model estimates a 15% chance this drug is eventually approved. It starts from the historical base rate for Phase 2 drugs in this area (about 27%), then adjusts using ten facts about the trial and sponsor. What moves the number most: it is helped by a non-randomized design and more secondary endpoints than usual; it is held back by the sponsor's thin or weak approval record and weak or limited earlier-phase results. The other facts land near average for this stage, so they leave the estimate roughly where the base rate put it.

Efficacy risk is real but bounded by class validation. EXPLORER-HCM reported a placebo-corrected mean post-exercise LVOT gradient reduction of approximately 35 mmHg at week 30 in the mavacamten arm [9]; that is the reasonable benchmark HRS-1893 needs to approach on placebo-corrected metrics to be credible. If the magnitude falls short, or if the tolerability profile shows the same LVEF-suppression issue that gave mavacamten its FDA warning about systolic dysfunction, positioning becomes difficult against aficamten, which in cross-trial (not head-to-head) comparison appeared to show less LVEF suppression [10]. Safety risk is mechanism-based and predictable. Inhibiting cardiac contractility works by design; over-inhibition drops ejection fraction and can precipitate heart failure. Mavacamten is dispensed under a REMS (Risk Evaluation and Mitigation Strategy, an FDA-mandated safety monitoring program) that requires echocardiography every four weeks during titration and every twelve weeks thereafter [8]. Any myosin inhibitor faces a similar monitoring burden unless it shows a substantially wider therapeutic index. HRS-1893's Phase 1 PK data was published, but pharmacodynamic markers of contractility suppression at therapeutic doses have not been made public [1]. Commercial risk is where this drug lives or dies outside China. Camzyos posted roughly $600M in 2024 per BMS's 10-K, and Myqorzo (aficamten) only became available in the US in early 2026 after December 2025 FDA approval, so cardiologists have less than a year of experience with the second entrant [11][13]. A third entrant needs a differentiation story: cheaper, safer, more convenient dosing, or better outcomes in a defined subgroup. Otherwise it becomes a China-only asset. Regulatory risk in the US is meaningful. China-generated Phase 3 data alone rarely supports first-cycle US approval without bridging studies, and FDA has not designated HRS-1893.

Watch, don't chase. The mechanism is settled, so HRS-1893 is an execution story more than a science story. The signals worth watching, in priority order: (1) top-line efficacy data from NCT06516068 on Valsalva-provoked LVOT gradient reduction (the outflow obstruction measured during a forced breath-hold that provokes worst-case obstruction) versus baseline, ideally with a placebo-controlled arm, this is the single most informative readout [14]; (2) LVEF changes and any protocol-mandated dose interruptions during the long-term safety Phase 2 (NCT07021963), which will telegraph the therapeutic-window story [5]; and (3) any Hengrui announcement of a Phase 3 initiation or a licensing deal with a Western partner, either of which would signal genuine commercial ambition beyond China. Check back in Q4 2026 through Q2 2027 for first Phase 2 obstructive HCM data. Realistic first commercial approval, China only, is 2028 at the earliest given typical NMPA timelines for cardiovascular Phase 2-to-approval. US pathway is 2029 or later if it happens at all through Hengrui alone, sooner with a Western licensee. The China commercial opportunity is meaningful but bounded: HCM prevalence estimates place several hundred thousand to low millions of patients in China, of which roughly two-thirds have the obstructive form, but domestic pricing is a fraction of US pricing and NMPA-approved competition already exists since Myqorzo received NMPA approval in December 2025 [13]. Context on the sponsor: Jiangsu Hengrui is one of the top three Chinese pharma companies by R&D spend, with a growing track record of out-licensing assets to Western partners (Merck for a PARP inhibitor, GSK for a GLP-1 program). Shandong Suncadia Medicine is the internal cardiovascular vehicle. Hengrui's demonstrated willingness to spin assets into out-licensing deals is the most credible path for HRS-1893 to matter outside China. The base case: real China product by 2028, uncertain ex-China future.