Secretome Therapeutics, a clinical-stage biotechnology company developing regenerative therapies derived from neonatal cardiac progenitor cells, has reported initial Phase 1 safety and exploratory clinical findings for STM-01 in patients with heart failure with preserved ejection fraction (HFpEF). In results announced on October 9, 2026, ahead of a scheduled presentation at the Heart Failure Society of America Annual Scientific Meeting on October 11, the company reported no treatment-related adverse events among 10 patients treated across two dose levels, alongside preliminary improvements in patient-reported health status.
The findings represent an early clinical assessment of an investigational cell-based therapy intended to influence inflammatory, fibrotic and tissue-repair processes associated with heart failure. Seven of the 10 participants experienced improvements exceeding five points on the Kansas City Cardiomyopathy Questionnaire, a validated instrument for evaluating heart failure symptoms, physical limitations and health-related quality of life. However, the study was open-label, involved no control group and followed patients for only 56 days, preventing firm conclusions about whether STM-01 caused the observed improvements.
The distinction between initial tolerability and established therapeutic benefit is particularly important because HFpEF has become an increasingly competitive cardiovascular treatment area. Sodium-glucose cotransporter-2 inhibitors, mineralocorticoid receptor antagonists and selected incretin-based treatments have expanded the available therapeutic options, creating a higher evidence standard for investigational products seeking a role in future care. STM-01 enters this environment with a different biological approach, but its development programme must eventually demonstrate benefits beyond those achievable with established medical therapy.
The October disclosure provides greater visibility into how STM-01 performed in its initial human HFpEF study, including adverse events, patient-reported outcomes, exercise capacity and selected cardiac measurements. It does not establish that the therapy reverses cardiac fibrosis, restores myocardial function, reduces hospitalisations or improves survival. Those more consequential questions remain dependent on appropriately controlled studies with larger patient populations and longer follow-up.
What did the 10-patient Phase 1 STM-01 study reveal about safety and tolerability in HFpEF?
The Phase 1 study evaluated STM-01 through an open-label, sequential dose-escalation design involving two groups of five patients with heart failure with preserved ejection fraction. Participants received intravenous infusions containing either 100 million or 200 million cells on Day 0 and Day 28, with safety and clinical follow-up extending through Day 56. The registered study, identified as NCT06560762, was designed primarily to assess treatment safety and tolerability rather than establish therapeutic efficacy, with exploratory clinical measurements included to guide subsequent development.
Secretome Therapeutics reported nine treatment-emergent adverse events involving five participants across the two cohorts. Investigators did not consider any of these events related to STM-01, and the company reported no treatment-related serious treatment-emergent adverse events, deaths, or adverse events leading to treatment discontinuation, withdrawal or interruption. These findings offer preliminary reassurance about short-term tolerability at the evaluated doses, although the announcement did not provide a detailed breakdown of individual adverse-event types and severity grades.
The absence of investigator-attributed treatment-related events is encouraging for a first-in-human programme involving intravenously administered cells. Nevertheless, a sample of 10 participants is too small to reliably identify uncommon adverse reactions, particularly those that may occur in fewer than one in several hundred treated patients. The 56-day observation period also provides limited information about potential delayed effects, repeated-dose tolerability beyond the tested schedule or the longer-term consequences of exposure to an allogeneic cellular product.
For a cell therapy, future safety evaluations may need to consider infusion reactions, immune responses, product-related variability and other risks associated with its specific cellular characteristics and manufacturing process. These considerations do not indicate that such complications occurred in the STM-01 study, but they illustrate why a favourable initial safety profile cannot substitute for larger and longer investigations. The disclosed findings support continued clinical evaluation rather than a definitive conclusion about the treatment’s safety across the broader HFpEF population.
Why does the reported improvement in seven patients’ KCCQ scores not establish STM-01 efficacy?
Among the exploratory findings, the Kansas City Cardiomyopathy Questionnaire results offer the clearest numerical indication of a possible clinical response. Secretome Therapeutics reported that seven of the 10 participants experienced improvements exceeding five points during the 56-day evaluation period. A five-point change is commonly used as a threshold for a small but potentially clinically meaningful change in heart failure health status, making the reported individual improvements relevant to future efficacy research.
However, achieving a meaningful within-patient improvement is different from demonstrating a treatment effect against an appropriate control group. Without randomisation or a placebo comparator, investigators cannot reliably separate effects associated with STM-01 from natural symptom fluctuations, changes in background treatment, patient expectations or variation in repeated assessments. The study’s open-label design is especially relevant because participants and investigators knew that the investigational treatment was being administered.
The company did not disclose a complete distribution of KCCQ changes, a placebo-adjusted treatment effect or a statistical comparison capable of establishing efficacy. The seven-patient finding therefore identifies a potential signal rather than confirming that STM-01 improves quality of life. It also remains unclear from the disclosed aggregate results whether improvements were concentrated in one dose cohort or distributed consistently across both groups.
Dose-response information will be important because the study evaluated cell quantities differing twofold between cohorts. A consistent relationship between exposure and clinical response could help guide dose selection, although such a pattern would remain preliminary in an uncontrolled study of this size. Conversely, similar outcomes across both doses would require evaluation alongside safety, biological activity and the practical requirements of manufacturing a larger cellular dose.
These distinctions make the KCCQ findings useful for designing a subsequent trial but insufficient for supporting claims of established therapeutic benefit. A randomised study could determine whether changes in patient-reported health status are meaningfully greater among STM-01 recipients than among patients receiving standard care and a suitable control intervention. It could also assess whether any initial improvement persists after the short observation period used in Phase 1.
What do the six-minute walk test and cardiac biomarker results suggest about STM-01’s activity?
The Phase 1 evaluation also included six-minute walk testing, echocardiography and circulating biomarkers, providing several ways to examine potential changes in cardiovascular function. Secretome Therapeutics reported a favourable overall trend in six-minute walk distance, suggesting that some participants demonstrated improved exercise capacity during follow-up. However, the company did not provide a detailed numerical treatment effect, a statistical significance result or a controlled comparison for the walking assessment in its October 9 disclosure.
Exercise capacity is an important consideration in HFpEF because patients frequently experience breathlessness, fatigue and limitations during physical activity despite retaining a relatively preserved left ventricular ejection fraction. The six-minute walk test can capture functional changes relevant to daily activity, although performance may also be influenced by motivation, familiarity with the test, musculoskeletal limitations and concurrent medical treatment. Repeated testing in a small uncontrolled study therefore provides useful exploratory information but cannot independently establish a therapeutic response.
The echocardiographic findings were less suggestive of a measurable short-term change in cardiac function. The company reported that E/e’, an echocardiographic measurement commonly used as part of assessing left ventricular filling pressure, and stroke volume remained broadly stable over the study period. Neither observation establishes structural improvement or reversal of the underlying disease process, although the relatively short follow-up may also limit the ability to detect changes in cardiac physiology.
The findings involving N-terminal pro-B-type natriuretic peptide, or NT-proBNP, introduce another important qualification. Secretome Therapeutics described heterogeneous responses and reported no statistically significant change in the biomarker, which is widely used in heart failure assessment and reflects myocardial wall stress. While NT-proBNP can be influenced by factors including obesity, kidney function and other clinical characteristics, the absence of a statistically significant change means the disclosed biomarker findings do not independently corroborate a meaningful improvement in cardiac status.
Taken together, the reported outcomes suggest that patient-reported symptoms and functional measurements may be worth examining in a larger study, but they do not yet provide a consistent physiological picture of STM-01 activity. Future trials could strengthen interpretation by evaluating symptoms, exercise capacity, biomarkers and echocardiographic measures together, with prespecified analyses and sufficient statistical power. Demonstrating agreement across multiple endpoints would help distinguish a reproducible therapeutic effect from the variability expected in a heterogeneous heart failure population.
How is Secretome Therapeutics attempting to target inflammation and fibrosis in preserved-ejection-fraction heart failure?
STM-01 is being developed from neonatal cardiac progenitor and related cardiac-derived cellular technology, with Secretome Therapeutics seeking to exploit biological activity associated with the cells’ secretome. A cellular secretome comprises substances released by cells, including proteins, signalling molecules and extracellular vesicles, some of which may influence surrounding tissues and immune responses. The company’s therapeutic hypothesis centres on the possibility that these biological effects can modulate inflammatory activity, fibrotic processes, angiogenesis and tissue repair in cardiovascular disease.
It is important to distinguish STM-01 itself from the company’s separate cell-free development programme. STM-01 is an investigational cellular therapy administered intravenously, while STM-21 is an investigational programme based on secretome components, including extracellular vesicles and exosomes. Although both programmes originate from related biological research, evidence generated for one formulation cannot automatically establish the effectiveness or safety of the other.
The biological rationale is relevant because HFpEF encompasses several overlapping disease mechanisms rather than a single uniform pathological process. Obesity, diabetes, hypertension, chronic kidney disease and other comorbidities can contribute to systemic inflammation, endothelial dysfunction and alterations in myocardial stiffness. In some patients, inflammatory signalling and fibrotic remodelling may contribute to impaired ventricular relaxation and exercise intolerance, creating a potential rationale for therapies directed at these pathways.
Secretome Therapeutics has described preclinical findings involving neonatal cardiac-derived cells and their secretome, including effects on inflammatory pathways and cardiac injury responses. Those findings provide a scientific basis for investigation, but they do not establish that STM-01 reverses fibrosis or produces regenerative effects in patients with HFpEF. The early clinical study also did not report direct human evidence demonstrating that the proposed biological mechanisms produced the observed KCCQ changes.
A key development challenge will therefore be connecting the therapy’s proposed mechanism to measurable human responses. Future research may need to identify biological markers of treatment activity, assess which HFpEF phenotypes are most likely to respond and determine whether any changes in inflammatory or fibrotic processes correspond with improvements in cardiovascular function. Such evidence would strengthen the programme’s rationale beyond the preliminary symptom measurements available from Phase 1.
How does STM-01 fit into the changing treatment landscape for heart failure with preserved ejection fraction?
The therapeutic environment for HFpEF has evolved substantially as treatments with demonstrated benefits have become available. Sodium-glucose cotransporter-2 inhibitors, including empagliflozin and dapagliflozin, have established a role in reducing heart failure events among patients with preserved or mildly reduced ejection fraction. The addition of finerenone, supported by the FINEARTS-HF programme and its expanded United States regulatory indication in 2025, has further strengthened the evidence base for treatment directed at cardiovascular outcomes.
The American College of Cardiology’s 2026 expert consensus pathway places sodium-glucose cotransporter-2 inhibitors and appropriate mineralocorticoid receptor antagonist treatment among the central components of contemporary HFpEF management. Selected patients with obesity-related HFpEF may also benefit from incretin-based therapies, including semaglutide or tirzepatide, depending on their clinical characteristics and the applicable treatment indication. This evolving therapeutic landscape means new investigational products must demonstrate a meaningful contribution beyond the benefits already achievable through existing approaches.
Secretome Therapeutics reported that most Phase 1 participants received STM-01 alongside treatment that included glucagon-like peptide-1-based therapies and sodium-glucose cotransporter-2 inhibitors. This provides some initial experience with STM-01 in patients receiving contemporary medications, although the company did not disclose a sufficiently detailed breakdown of background treatment to establish how these therapies influenced individual outcomes. The concurrent use of effective medications also complicates interpretation of uncontrolled improvements in symptoms or exercise performance.
For STM-01, a commercially and clinically credible development strategy would likely require evidence of additional benefit when used alongside appropriate standard treatment. Potential outcomes include improved health status, exercise capacity or a reduction in worsening heart failure events, but each would require prospective evaluation rather than extrapolation from the current dataset. The therapy’s intravenous administration and cellular manufacturing requirements would also need to be considered against established oral or subcutaneous treatment options.
The broader HFpEF population is heterogeneous, and a treatment targeting inflammation or tissue repair may not produce equivalent effects across every clinical phenotype. Patients with predominantly obesity-related disease, advanced fibrosis, pulmonary vascular abnormalities or other underlying conditions may differ in both biological response and baseline risk. Identifying a suitable population could therefore become an important part of STM-01’s future development, although the current study does not provide enough evidence to define a validated responder subgroup.
What manufacturing and regulatory challenges could shape STM-01’s future development?
Unlike conventional small-molecule heart failure medications, STM-01 is a biologic cellular product whose development requires attention to cell identity, manufacturing consistency, biological potency and product stability. Manufacturing controls are especially important for therapies whose proposed effects depend on complex biological activities rather than a single readily measurable molecular interaction. Regulators would need adequate evidence that the characteristics of material used in clinical trials remain sufficiently consistent as production processes are developed and scaled.
Secretome Therapeutics has described its technology as an allogeneic, off-the-shelf cell therapy approach, meaning the intended product is derived from donor-origin cells rather than manufactured individually from each patient’s own cells. This approach could offer production and distribution advantages if consistent manufacturing and storage processes can be established. However, the company has not disclosed enough current commercial-scale manufacturing information to assess production capacity, expected cost per treatment or readiness for widespread clinical supply.
Dose selection will also be important because Phase 1 evaluated 100-million-cell and 200-million-cell regimens without publicly establishing a preferred dose for future HFpEF studies. A larger dose is not necessarily more effective, and increasing administered cell quantities could affect manufacturing requirements and safety considerations without guaranteeing additional therapeutic benefit. Dose selection should therefore be informed by the complete clinical, biological and safety dataset rather than by the numerical size of the administered dose alone.
STM-01 remains investigational and has not received regulatory approval for treatment of HFpEF. The reported Phase 1 findings do not establish an approvable evidence package, and subsequent development would require appropriately designed clinical investigations addressing efficacy and safety in a substantially larger population. No confirmed HFpEF Phase 2 initiation date or definitive pivotal development timeline was provided in the October 9 announcement.
Why is the broader STM-01 pipeline relevant to Secretome Therapeutics’ development strategy?
The HFpEF data form part of a wider development programme examining STM-01 across cardiovascular and neuromuscular conditions. Secretome Therapeutics also lists programmes involving dilated cardiomyopathy and Duchenne muscular dystrophy-associated cardiomyopathy, conditions in which cardiac injury, inflammation and fibrosis may contribute to disease progression. This approach gives the company opportunities to investigate its underlying cellular technology in multiple clinical settings, although results from one indication cannot be assumed to predict outcomes in another.
On September 29, 2026, Secretome Therapeutics announced the initiation of THRIVE-2, an open-label Phase 2 study evaluating STM-01 in patients with Duchenne muscular dystrophy. The study was described as open for enrolment, with the first participant expected to enter the programme subsequently. THRIVE-2 is intended to evaluate safety and efficacy through assessments involving skeletal muscle and cardiac function, reflecting a distinct clinical development objective from the Phase 1 HFpEF study.
The progression into Phase 2 development for Duchenne muscular dystrophy does not mean that STM-01 has established efficacy in HFpEF or that the two clinical programmes are at equivalent stages. Different patient populations, disease mechanisms, outcome measures and treatment durations will require separate clinical evidence. Nevertheless, the programmes may generate complementary information about administration, tolerability, product consistency and biological activity that could inform broader development decisions.
Secretome Therapeutics is privately held, and the October HFpEF announcement does not provide a publicly traded share price or a reliable market-based assessment of investor reaction. From a financing perspective, the more consequential milestones will involve controlled clinical evidence, the selection of future development pathways and demonstration that the cellular platform can be manufactured consistently. The company has not disclosed a detailed financing requirement specifically for the next HFpEF study.
What should clinicians and biotechnology investors watch after the HFSA 2026 STM-01 presentation?
The scheduled presentation by Ambarish Pandey at the Heart Failure Society of America Annual Scientific Meeting on October 11 provides an opportunity for the cardiovascular research community to examine the initial STM-01 findings in greater detail. Pandey, now affiliated with the University of Michigan, is scheduled to present the Phase 1 experience as part of the meeting’s oral abstract programme in Phoenix, Arizona. The company’s October 9 release provides the principal numerical results available ahead of that presentation, but it is not a substitute for a complete clinical dataset or peer-reviewed publication.
Additional details about adverse-event classification, individual patient responses, baseline characteristics and outcomes by dose cohort would help clarify the interpretation of the early study. Particular attention is likely to focus on whether the reported KCCQ and walking-distance trends are consistent across patients and whether biological measurements support the proposed treatment mechanism. More complete information about concomitant medications would also help investigators understand the extent to which existing therapies may have contributed to changes observed during follow-up.
The central development decision will be whether the early safety findings and exploratory clinical measurements justify a randomised HFpEF study, and what that study should be designed to demonstrate. A controlled trial with sufficient enrolment and follow-up could assess whether STM-01 improves clinically relevant outcomes beyond standard treatment, while also providing a more informative assessment of safety and dose selection. Longer observation would be particularly valuable for evaluating the durability of any functional improvement and identifying adverse effects that cannot be meaningfully assessed during a 56-day study.
For now, STM-01 has produced a preliminary tolerability dataset and several exploratory clinical observations, including improvements in patient-reported health status among seven participants. Those findings justify scientific interest but do not yet establish a reliable treatment effect, particularly given the absence of statistically significant NT-proBNP changes and broadly stable echocardiographic measurements. Secretome Therapeutics’ next challenge is to establish whether the biological activity proposed for its cellular platform can translate into reproducible, clinically meaningful benefit for patients with HFpEF receiving contemporary heart failure therapy.
