Povsic, Thomas J.

Abstract Patients with heart failure experience limitations in daily activity and poor quality-of-life. Prospective surveillance of health-related quality-of-life supplemented traditional death and hospitalization outcomes in the multinational, randomized, double-blinded CHART-1 clinical trial that assessed cardiopoiesis-guided cell therapy in ischemic heart failure patients with reduced left ventricular ejection fraction. The Minnesota Living with Heart Failure Questionnaire (MLHFQ), a Food and Drug Administration qualified instrument for evaluating therapeutic effectiveness, was applied through the 1-year follow-up. Cell treated (n = 109) and sham procedure (n = 140) cohorts reported improved MLHFQ scores comparable between the 2 study arms (mean treatment difference with baseline adjustment −3.2 points, P = .107). Superiority of cell treatment over sham in betterment of the MLHFQ score was demonstrated in patients with pre-existing advanced left ventricular enlargement (baseline-adjusted mean treatment difference −6.4 points, P = .009). In this highly responsive subpopulation, benefit on the MLHFQ score paralleled reduction in death and hospitalization post-cell therapy (adjusted Mann-Whitney odds 1.43, 95% CI, 1.01-2.01; P = .039). The potential of cell therapy in addressing the quality-of-life dimension of heart failure requires further evaluation for disease relief.

Stem cell and regenerative approaches that might rejuvenate the heart have immense intuitive appeal for the public and scientific communities. Hopes were fueled by initial findings from preclinical models that suggested that easily obtained bone marrow cells might have significant reparative capabilities; however, after initial encouraging pre-clinical and early clinical findings, the realities of clinical development have placed a damper on the field. Clinical trials were often designed to detect exceptionally large treatment effects with modest patient numbers with subsequent disappointing results. First generation approaches were likely overly simplistic and relied on a relatively primitive understanding of regenerative mechanisms and capabilities. Nonetheless, the field continues to move forward and novel cell derivatives, platforms, and cell/device combinations, coupled with a better understanding of the mechanisms that lead to regenerative capabilities in more primitive models and modifications in clinical trial design suggest a brighter future.

Abstract The concept that cell-based repair of myocardial injury might be possible was introduced almost two decades ago; however, the field of cardiovascular reparative medicine has been criticized as translation to clinically effective approaches has been slow. The recent retraction of a series of papers has further impacted perception of this area of research. As researchers, clinicians, and teachers in this field, we felt it incumbent to critically appraise the current state of cardiac cell repair, determine what can be learned from past mistakes, and formulate best practices for future work. This special communication summarizes an introspective assessment of what has fallen short, how to prevent similar issues, and how the field might best move forward in the service of science and patients.

Abstract Aims This study aims to explore long-term clinical outcomes of cardiopoiesis-guided stem cell therapy for ischaemic heart failure assessed in the Congestive Heart Failure Cardiopoietic Regenerative Therapy (CHART-1) trial. Methods and results CHART-1 is a multinational, randomized, and double-blind trial conducted in 39 centres in heart failure patients (n = 315) on standard-of-care therapy. The ‘active’ group received cardiopoietic stem cells delivered intramyocardially using a retention-enhanced catheter. The ‘control’ group underwent patient-level sham procedure. Patients were followed up to 104 weeks. In the entire study population, results of the primary hierarchical composite outcome were maintained neutral at Week 52 [Mann–Whitney estimator 0.52, 95% confidence interval (CI) 0.45–0.59, P = 0.51]. Landmark analyses suggested late clinical benefit in patients with significant left ventricular enlargement receiving adequate dosing. Specifically, beyond 100 days of follow-up, patients with left ventricular end-diastolic volume of 200–370 mL treated with ≤19 injections of cardiopoietic stem cells showed reduced risk of death or cardiovascular hospitalization (hazard ratio 0.38, 95% CI 0.16–0.91, P = 0.031) and cardiovascular death or heart failure hospitalization (hazard ratio 0.28, 95% CI 0.09–0.94, P = 0.040). Cardiopoietic stem cell therapy was well tolerated long term with no difference in safety readouts compared with sham at 2 years. Conclusions Longitudinal follow-up documents that cardiopoietic stem cell therapy is overall safe, and post hoc analyses suggest benefit in an ischaemic heart failure subpopulation defined by advanced left ventricular enlargement on tolerable stem cell dosing. The long-term clinical follow-up thus offers guidance for future targeted trials.

Abstract Aims Left ventricular (LV) reverse remodelling is an important marker of improved outcomes in patients with advanced heart failure (HF). We examined the impact of the intramyocardial administration of bone-marrow-derived, lineage-directed, autologous cardiopoietic mesenchymal stem cells (C3BS-CQR-1) on LV remodelling in patients with advanced HF enrolled in the CHART-1 study. Methods and results Patients (n=351) with symptomatic advanced HF secondary to ischaemic heart disease, and reduced LV ejection fraction (LVEF <35%) were randomized to receive C3BS-CQR-1 or a sham procedure. In a post hoc analysis we examined the effect of C3BS-CQR-1 on LV reverse remodelling within 1 year of the procedure and the influence of C3BS-CQR-1 dosing in the 271 patients treated as randomized. Delivery of C3BS-CQR-1 was associated with a progressive decrease in both LV end-diastolic volume (LVEDV) and end-systolic volume (LVESV) within 52 weeks after treatment. At 1 year, the LVEDV and LVESV of treated patients decreased by 17.0 mL and 12.8 mL greater than controls (P=0.006 and P=0.017, respectively). The effect on LVEDV was maintained after multivariable adjustment for baseline age, systolic blood pressure, LVEDV, LVEF and history of myocardial infarction. The largest reverse remodelling was evident in the patients receiving a moderate number of injections (<20). Conclusion In CHART-1, intramyocardial administration of cardiopoietic stem cells led to reverse remodelling as evidenced by significant progressive decreases in LVEDV and LVESV through the 52 weeks of follow-up. Further studies are needed to explore the dose response with regard to cell number and injected volume, and reverse remodelling.

An increasing number of patients have refractory angina despite optimal medical therapy and are without further revascularization options. Preclinical studies indicate that human CD34 + stem cells can stimulate new blood vessel formation in ischemic myocardium, improving perfusion and function. In ACT34-CMI ( N = 167), patients treated with autologous CD34 + stem cells had improvements in angina and exercise time at 6 and 12 months compared to placebo; however, the longer-term effects of this treatment are unknown. ACT34 was a phase II randomized, double-blind, placebo-controlled clinical trial comparing placebo, low dose (1 × 10 5 CD34/kg body weight), and high dose (5 × 10 5 CD34/kg) using intramyocardial delivery into the ischemic zone following NOGA ® mapping. To obtain longer-term safety and efficacy in these patients, we compiled data of major adverse cardiac events (MACE; death, myocardial infarction, acute coronary syndrome, or heart failure hospitalization) up to 24 months as well as angina and quality of life assessments in patients who consented for 24-month follow-up. A total of 167 patients with class III–IV refractory angina were randomized and completed the injection procedure. The low-dose-treated patients had a significant reduction in angina frequency ( p = 0.02, 0.035) and improvements in exercise tolerance testing (ETT) time ( p = 0.014, 0.017) compared to the placebo group at 6 and 12 months. At 24 months, patients treated with both low-and high-dose CD34 + cells had significant reduction in angina frequency ( p = 0.03). At 24 months, there were a total of seven deaths (12.5%) in the control group versus one (1.8%) in the low-dose and two (3.6%) in the high-dose ( p = 0.08) groups. At 2 years, MACE occurred at a rate of 33.9%, 21.8%, and 16.2% in control, low-, and high-dose patients, respectively ( p = 0.08). Autologous CD34 + cell therapy was associated with persistent improvement in angina at 2 years and a trend for reduction in mortality in no-option patients with refractory angina.

Abstract Aims Cardiopoiesis is a conditioning programme that aims to upgrade the cardioregenerative aptitude of patient-derived stem cells through lineage specification. Cardiopoietic stem cells tested initially for feasibility and safety exhibited signs of clinical benefit in patients with ischaemic heart failure (HF) warranting definitive evaluation. Accordingly, CHART-1 is designed as a large randomized, sham-controlled multicentre study aimed to validate cardiopoietic stem cell therapy. Methods Patients (n = 240) with chronic HF secondary to ischaemic heart disease, reduced LVEF (<35%), and at high risk for recurrent HF-related events, despite optimal medical therapy, will be randomized 1:1 to receive 600 × 106 bone marrow-derived and lineage-directed autologous cardiopoietic stem cells administered via a retention-enhanced intramyocardial injection catheter or a sham procedure. The primary efficacy endpoint is a hierarchical composite of mortality, worsening HF, Minnesota Living with Heart Failure Questionnaire score, 6 min walk test, LV end-systolic volume, and LVEF at 9 months. The secondary efficacy endpoint is the time to cardiovascular death or worsening HF at 12 months. Safety endpoints include mortality, readmissions, aborted sudden deaths, and serious adverse events at 12 and 24 months. Conclusion The CHART-1 clinical trial is powered to examine the therapeutic impact of lineage-directed stem cells as a strategy to achieve cardiac regeneration in HF populations. On completion, CHART-1 will offer a definitive evaluation of the efficacy and safety of cardiopoietic stem cells in the treatment of chronic ischaemic HF. Trial registration: NCT01768702