A phase II study of belumosudil for chronic graft-versus-host disease in patients who failed at least one line of systemic therapy in China

BACKGROUND

Chronic graft-versus-host disease (cGVHD) is an immune-related disorder that is the most common complication post-allogenic hematopoietic stem cell transplant. Corticosteroids with or without calcineurin inhibitors (CNIs) remain the mainstay of cGVHD treatment for first-line therapy. However, for many patients, cGVHD symptoms cannot be effectively managed and thus require second-line therapy. Currently, there is no approved treatment for second-line cGVHD treatment in China. In this study, belumosudil, a highly selective and potent rho-associated coiled-coil-containing protein kinase-2 inhibitor demonstrated to be effective for cGVHD in the United States and other Western countries, is investigated in patients with cGVHD in China for its overall benefit-risk balance.

METHODS

This multicenter, open-label phase II study evaluated the safety, efficacy, and pharmacokinetics of oral belumosudil 200 mg once daily in cGVHD patients who had been treated with at least one line of systemic therapy in China. The primary endpoint was overall response rate (ORR); each individual patient's response was assessed by the investigator using the 2014 National Institutes of Health consensus criteria. Secondary endpoints were duration of response (DOR), time to response (TTR), changes in Lee Symptom Scale (LSS) score, organ response rate, corticosteroid dose change, CNI dose change, failure-free survival, time-to-next-treatment, overall survival, and safety.

RESULTS

Thirty patients were enrolled in the study with a median follow-up time of 12.9 months. ORR was 73.3% (95% confidence interval: 54.1-87.7%) and all responders achieved partial response. Median DOR among responders was not reached and median TTR was 4.3 weeks (range: 3.9-48.1). Fifteen patients (50.0%) achieved clinically meaningful response in terms of reduction in LSS score by ≥ 7 points from baseline. Corticosteroid and CNI dose reductions were reported in 56.7% (17/30) and 35.0% (7/20) of patients, respectively. Most treatment-emergent adverse events (TEAEs) were mild to moderate in severity, with 11 patients (36.7%) experiencing grade ≥ 3 TEAEs. The most common grade ≥ 3 TEAE was pneumonia (n = 5, 16.7%).

CONCLUSIONS

Belumosudil treatment demonstrated a favorable benefit-risk balance in treating cGVHD patients who previously have had standard corticosteroid therapy in China where approved second-line setting is absent.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT04930562.

Unraveling the rationale and conducting a comprehensive assessment of KD025 (Belumosudil) as a candidate drug for inhibiting adipogenic differentiation-a systematic review

Rho-associated kinases (ROCKs) are crucial during the adipocyte differentiation process. KD025 (Belumosudil) is a newly developed inhibitor that selectively targets ROCK2. It has exhibited consistent efficacy in impeding adipogenesis across a spectrum of in vitro models of adipogenic differentiation. Given the novelty of this treatment, a comprehensive systematic review has not been conducted yet. This systematic review aims to fill this knowledge void by providing readers with an extensive examination of the rationale behind KD025 and its impacts on adipogenesis. Preclinical evidence was gathered owing to the absence of clinical trials. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and the study's quality was assessed using the Joanna Briggs Institute (JBI) Checklist Critical Appraisal Tool for Systematic Reviews. In various in vitro models, such as 3T3-L1 cells, human orbital fibroblasts, and human adipose-derived stem cells, KD025 demonstrated potent anti-adipogenic actions. At a molecular level, KD025 had significant effects, including decreasing fibronectin (Fn) expression, inhibiting ROCK2 and CK2 activity, suppressing lipid droplet formation, and reducing the expression of proadipogenic genes peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα). Additionally, KD025 resulted in the suppression of fatty acid-binding protein 4 (FABP4 or AP2) expression, a decrease in sterol regulatory element binding protein 1c (SREBP-1c) and Glut-4 expression. Emphasis must be placed on the fact that while KD025 shows potential in preclinical studies and experimental models, extensive research is crucial to assess its efficacy, safety, and potential therapeutic applications thoroughly and directly in human subjects.

Belumosudil Impacts Immunosuppression Pharmacokinetics in Patients with Chronic Graft-versus-Host Disease

Belumosudil (BEL) is a novel Rho-associated coiled-coil containing protein kinase 2 (ROCK2) inhibitor approved for the treatment of chronic graft-versus-host disease (cGVHD) in patients who have failed 2 or more prior lines of systemic therapy. Although the pharmacokinetic effects of BEL on other immunosuppressive (IS) agents have not been clinically evaluated, in vitro data indicate that BEL may have possible interactions with drugs with a narrow therapeutic index used to treat cGVHD, such as tacrolimus, sirolimus, and cyclosporine, through cytochrome P450 (CYP3A) and p-glycoprotein interactions. Further evaluation of these potential interactions is warranted to optimize the safety and effectiveness of these medications when combined with BEL. In this study, we investigated the potential effects of BEL on sirolimus and tacrolimus levels when used concurrently by assessing changes in IS levels after the addition of BEL. This retrospective single-center study of patients who started BEL while on tacrolimus and/or sirolimus between February 1, 2019, to February 1, 2023, included patients who had IS levels measured at baseline prior to starting BEL and at least 1 subsequent IS measurement to assess changes over time. The primary endpoint was the concentration-dose (C/D) ratio analyzed before and after the addition of BEL. Secondary endpoints included the incidence of IS levels outside of the therapeutic range (subtherapeutic or supratherapeutic) and mean dosage changes over time. Thirty-seven patients met our eligibility criteria and were included in this analysis. Patients taking sirolimus (n = 30) or tacrolimus (n = 16) concurrently with BEL had a statistically significant increase in the C/D ratio (sirolimus recipients, 160% [P < .001]; tacrolimus recipients, 113% [P = .013]) between the pre-BEL and final post-BEL assessments. The C/D ratios for both tacrolimus and sirolimus recipients continued to increase at several time points after initiation of BEL, indicating that multiple drug dosage adjustments may be required. After BEL initiation, 19% of tacrolimus levels and 57% of sirolimus levels were supratherapeutic. Despite dosage adjustments, 27% of tacrolimus levels were supratherapeutic at both the second and third assessments after starting BEL, and 28% and 30% of sirolimus levels were supratherapeutic at these 2 time points, respectively. All 12 of the patients who discontinued BEL during the study period (100%) showed a return to their baseline C/D ratio, confirming that the C/D ratio change can be attributed to BEL. The impact of BEL on IS levels is clinically significant, warranting dosage adjustments of concurrent medications. A significant number of patients taking sirolimus with BEL had levels >15 ng/mL during the study period, indicating a potential risk for toxicity if this interaction is unmonitored. We recommend empiric dose reductions of 25% for tacrolimus and 25% to 50% for sirolimus when adding BEL, as well as close monitoring of IS levels during the initial weeks of BEL therapy. Future studies are warranted to better describe the impact of BEL on patients taking CYP3A inhibitors.

Correlation of Patient-Reported Outcomes with Clinical Organ Responses: Data from the Belumosudil Chronic Graft-versus-Host Disease Studies

Chronic graft-versus-host disease (GVHD) is a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT) owing to both the disease itself and the immunosuppressive agents used for treatment. Response criteria endorsed by the National Institutes of Health (NIH) Consensus Conference on Clinical Trials in chronic GVHD include both clinician-documented measures and patient-reported outcomes (PROs) since both are considered clinical benefits by the Food and Drug Administration. The correlation between clinically assessed responses in organs and PRO improvements in organ-specific symptoms has not been investigated in depth. We used data from 2 published studies of belumosudil, an oral rho-associated coiled-coil-containing protein kinase-2 (ROCK2) inhibitor, for chronic GVHD to test the correlation between clinical and PRO outcomes. Participants completed PROs at enrollment and every 1 to 2 cycles according to the study design. Individual organ responses (complete plus partial response) and clinically meaningful changes in PROs were defined according to published methods. Generalized estimating equation methods were used to correlate changes in PROs associated with clinical responses according to NIH criteria, accounting for missing information and repeated measures. Data from all doses in both trials were included without stratification. The liver and genital tract were not included owing to a lack of site-specific PROs. Our pooled analysis of clinical and PRO data included 170 patients enrolled in 2 belumosudil studies (NCT02841995, n = 54; NCT03640481, n = 132) for whom we had baseline PROs, at least 1 follow-up PRO, and at least 1 response assessment. There was a strong positive correlation between complete and partial organ and overall responses and changes in PRO symptom scores, as well as clinically meaningful improvements. For all organs except joints, esophagus, and lower gastrointestinal tract, there was at least 1 PRO statistically correlated with NIH organ response. These data support the use of PROs for response assessment to document clinically meaningful benefit in chronic GVHD clinical trials.

Belumosudil, ROCK2-Specific Inhibitor, alleviates cardiac fibrosis by inhibiting cardiac fibroblasts activation

Cardiac fibrosis is thought to be the hallmark of pathological hypertrophic remodeling, of which the myofibroblasts transdifferentiation is the key cell biological event. However, there is still no specific and effective therapeutic agent approved for cardiac fibrosis. To investigate the effects of Belumosudil, the first ROCK2-specific inhibitor, on cardiac hypertrophy, fibrosis and dysfunction induced by pressure overload, the transverse aortic constriction (TAC) or sham operation was carried out on wild-type C57BL/6 mice (male, 6-8 week old) under pentobarbital anesthesia. After that, mice were randomly divided into three groups: sham operation + vehicle, TAC + vehicle, TAC + 50 mg·kg^-1·d^-1 Belumosudil. We found that Belumosudil effectively ameliorated cardiac hypertrophy, fibrosis and dysfunction in TAC mice. To elucidate the underlying mechanism, we inhibited the expression of ROCK2 in vitro by either Belumosudil or siRNA. We showed that the inhibition of ROCK2 by either Belumosudil or knockdown suppressed cardiac fibroblasts activation and proliferation significantly induced by Transforming Growth Factor-β1 (TGF-β1). Furthermore, our study confirmed ROCK2 mediates cardiac fibrosis by interacting with Transforming Growth Factor-β1 (TGF-β1)/mothers against decapentaplegic homolog (Smad2) pathway. Taken together, we demonstrated that Belumosudil ameliorates cardiac hypertrophy and fibrosis induced by TAC via inhibiting cardiac fibroblasts activation. In conclusion, Belumosudil may be a promising therapeutic drug for cardiac hypertrophy and fibrosis induced by myocardial pressure overload.

Belumosudil with ROCK-2 inhibition: chemical and therapeutic development to FDA approval for the treatment of chronic graft-versus-host disease

Belumosudil (BLM) is a ROCK inhibitor that has been firstly developed by Surface Logix, later acquired by Kadmon Pharmaceuticals for the treatment of chronic graft-versus-host disease (cGVHD), Psoriasis Vulgaris (PV), idiopathic pulmonary fibrosis (IPF), hepatic impairment (HI), diffuse cutaneous systemic sclerosis (dcSSc). BLM received a breakthrough therapy designation and priority review from the FDA, which reviewed the NDA under the real-time oncology review (RTOR) pilot programme and approved it six weeks ahead of the PDUFA deadline of August 30, 2021. On July 16^th, 2021, The USFDA authorized BLM under the brand name REZUROCK^TM for the treatment of cGVHD in adults and pediatric patients aged ≥ 12 years after the failure of at least two prior lines of systemic therapy. It has been granted orphan drug status by the FDA on August 9, 2020, for the treatment of systemic sclerosis. The European Union (EU) granted Quality Regulatory Clinical Ireland Limited, Ireland, orphan drug status for BLM (KD025) for the treatment of cGVHD on October 17, 2019. BLM is under regulatory assessment by Therapeutic Good Administration (TGA) Australia, Health Canada, MHRA (UK), and The Swiss Agency for Therapeutic Products (Swissmedic), Switzerland for cGVHD. A clinical trial is ongoing in the United States for cutaneous systemic sclerosis. This review article summarizes the milestones in the development of BLM chemistry, Chemical synthesis and development, mechanism of action, pharmacokinetics (PK), pharmacodynamics (PD), adverse effects, regulatory status, and ongoing clinical trials (CT) of BLM.

ROCK2, a critical regulator of immune modulation and fibrosis has emerged as a therapeutic target in chronic graft-versus-host disease

Chronic graft-versus-host disease (cGVHD) is an immune-mediated disorder characterized by chronic inflammation and fibrosis. Rho-associated coiled-coil-containing protein kinases (ROCKs) are key coordinators of tissue response to injury, regulating multiple functions, such as gene expression and cell migration, proliferation and survival. Relevant to cGVHD and autoimmunity, only the ROCK2 isoform drives a pro-inflammatory type 17 helper T (Th17) cell response. Moreover, ROCK2 inhibition shifts the Th17/regulatory T (Treg) cell balance toward Treg cells and restores immune homeostasis in animal models of autoimmunity and cGVHD. Furthermore, the selective inhibition of ROCK2 by belumosudil reduces fibrosis by downregulating both transforming growth factor-β signaling and profibrotic gene expression, thereby impeding the creation of focal adhesions. Consistent with its anti-inflammatory and antifibrotic activities, belumosudil has demonstrated efficacy in clinical studies, resulting in an overall response rate of >70% in patients with cGVHD who failed 2 to 5 prior lines of systemic therapy. In summary, selective ROCK2 inhibition has emerged as a promising novel therapeutic approach for treating cGVHD and other immunologic diseases with unique mechanisms of action, targeting both immune imbalance and detrimental fibrotic responses.