Efficacy of vamorolone in treatment of Duchene muscle dystrophy. A meta-analysis

The latest developments in synthetic approaches to Duchenne muscular dystrophy

INTRODUCTION

Duchenne muscular dystrophy (DMD) is a rare X-linked genetic disorder caused by mutations in the dystrophin gene, leading to an almost complete absence of dystrophin, which is essential for muscle cell structure and function. This resulting muscle deterioration and fibrosis, eventually causes respiratory failure and cardiomyopathy. While there is currently no cure, existing therapies aim to prolong survival and alleviate symptoms.

AREAS COVERED

This paper reviews current and emerging therapies for DMD, focusing on their safety and efficacy. Although corticosteroids remain the standard treatment, newly approved drugs such as exon-skipping therapies, vamorolone, delandistrogene moxeparvovec, and givinostat provide new treatment options. Additionally, future therapies, including gene therapy, stem cell treatments, and anti-fibrotic agents, show promise for clinical application.

EXPERT OPINION

Advancements in DMD treatments have expanded patient options. While gene therapy offers potential for correcting the genetic defect and alleviating symptoms, corticosteroids remain the most cost-effective and well-researched treatment. This is partly due to the lack of compelling long-term safety and efficacy data for gene therapies. The accelerated FDA review process has enabled faster approval of new medications; however many have provided minimal clinical benefit to patients. Despite these challenges, continued drug development and innovative research offer hope to patients.

The Potential of Targeting APE1/Ref-1 as a Therapeutic Intervention for Duchenne Muscular Dystrophy

Significance: Inflammation and oxidative stress play crucial roles in the development and progression of skeletal muscle diseases. This review aims to examine the existing evidence regarding the involvement and inhibition of APE1/Ref-1 (apurinic/apyrimidinic endonuclease 1/redox factor 1) in diseases, then extrapolate this evidence to the context of skeletal muscle and discuss the potential beneficial effects of APE1/Ref-1 inhibition in ameliorating myopathy with a particular focus on dystrophic pathology. Critical Issues: Currently, therapeutic interventions targeting pathways, such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and nuclear factor erythroid 2-related factor 2 (NRF2), have shown limited efficacy in both clinical and preclinical settings. Thus, there is a need for a more comprehensive treatment approach. Recent Advances: APE1/Ref-1 is a multifunctional protein that was initially identified as being involved in DNA repair. However, newer research has revealed its additional role as a redox-sensitive regulator of transcription factors, including NF-κB and NRF2. Numerous studies have reported increased expression of APE1/Ref-1 in various disorders and have demonstrated the beneficial effects of inhibiting its redox function using the small molecular inhibitor, APX3330. Although these pathways are similarly dysregulated in neuromuscular disorders, the specific role of APE1/Ref-1 in skeletal muscle remains unclear, with only a limited number of studies noting its presence in this tissue. Future Directions: Further studies investigating the role of APE1/Ref-1 in skeletal muscle and identifying whether APE1/Ref-1 is up- or downregulated in dystrophic skeletal muscle would be required to determine whether upregulating or inhibiting the redox function of APE1/Ref-1 will alleviate chronic inflammation and heightened oxidative stress. Antioxid. Redox Signal. 00, 000-000.

Meta-analysis of the efficacy and safety of vamorolone in Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is a severe neuromuscular disorder, often leading to wheelchair dependence by age 13 with limited treatment options, largely relying on glucocorticosteroids. We assessed the efficacy and safety of vamorolone, a modified synthetic corticosteroid, for DMD.

METHODS

We performed a systematic review and meta-analysis using seven databases including prospective studies comparing vamorolone with glucocorticosteroids or placebo in DMD patients. We extracted data on efficacy and safety outcomes. We built fixed effects models to assess mean differences. (PROSPERO: CRD42023396908).

RESULTS

Out of 210 identified records, two study reports were included in meta-analysis providing data from 210 patients. Vamorolone at 2.0 mg/kg/day was associated with improvement time to climb four stairs velocity (MD = 0.05 95% CI [0.03 to 0.08] P = 0.0002), and time stand from supine velocity (MD = 0.07 95% CI [0.01 to 0.07] P = 0.007). A higher dose of 6.0 mg/kg/day was additionally associated with higher time to run/walk 10 m velocity (MD = 0.10 95% CI [-0.0.1 to 0.21] P = 0.07, I2 = 0%). Among these beneficial effects only improvement in time to climb four stairs velocity was sustained after a follow-up period of 30 months. Vamorolone did not inhibit growth but increased the risk of weight gain, suppression of adrenal function, and insulin resistance.

CONCLUSION

The results of our systematic review and meta-analyis are suggestive of improved efficacy and safety of vamorolone for DMD compared to standard glucocorticosteroids but the external validity of these findings as well as the medication's long-term effects remain to be determined.

Efficacy and Safety of Vamorolone in Duchenne Muscular Dystrophy: A Systematic Review

BACKGROUND

Vamorolone has recently been approved for the management of Duchenne muscular dystrophy to replace glucocorticosteroids, which theoretically have more side effects. However, its efficacy and safety profile is unclear.

OBJECTIVE

We aimed to assess the efficacy of vamorolone in Duchenne muscular dystrophy through the 6-minute walk test (6MWT), the North Star Ambulatory Assessment (NSAA), time to stand velocity (TTSTAND), time to run 10 m (TTRW), time to climb four stairs (TTCLIMB) and a safety profile.

METHODS

A systematic search was conducted in MEDLINE, Scopus, Web of Science and the Cochrane Library from inception to June 2024 (PROSPERO: CRD42024558413) for studies evaluating the effect or safety profile of vamorolone in a population with Duchenne muscular dystrophy on 6MWT, NSAA and TTSTAND. TTRW, TTCLIMB and a safety profile were included. The risk of bias was assessed using the Cochrane Collaboration's risk of bias tool (RoB2) and the Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group from the US National Institutes of Health National Heart, Lung, and Blood Institute, depending on the type of design. Results were expressed as mean differences or proportions with 95% confidence intervals (CIs), depending on the outcome.

RESULTS

Six studies with a total of 145 individuals with Duchenne muscular dystrophy and a baseline age between 4.7 and 5.5 years were included in the systematic review. Overall, the most effective dose was 6 mg/kg/day. At 24 weeks, this dose showed a statistically significant effect compared with the untreated cohorts of 41.60 m (95% CI 14.30, 68.90) on the 6MWT, 3.57 points (95% CI 1.89, 5.25) on the NSAA, 0.06 events/s (95% CI 0.02, 0.10) on the TTSTAND, approximately 0.25 m/s on the TTRW and 0.04 (95% CI -0.00, 0.08) to 0.07 events/s (95% CI 0.03, 0.11) on the TTCLIMB. There was some discrepancy in the statistical significance of some studies, although the direction of the effect was usually similar. In general, the effect was maintained in the extension studies. Adverse events were less frequent than in historical cohorts treated with glucocorticoids. Finally, the risk of bias in the included studies was low.

CONCLUSIONS

According to our results, vamorolone offers a statistically and clinically significant benefit in the management of Duchenne muscular dystrophy, with fewer side effects than glucocorticoids. However, the number of studies limits the interpretability and generalisability of these data, requiring more studies with more participants to perform a meta-analysis.

Efficacy and safety of different doses of vamorolone in boys with Duchenne muscular dystrophy: a systematic review and network meta-analysis

Background and objectives

Several recent clinical studies have indicated that vamorolone is comparable in effectiveness to glucocorticosteroids for treating Duchenne muscular dystrophy (DMD). However, there is a lack of extensive data regarding the efficacy and safety of various doses of vamorolone. We conducted a study to evaluate the efficacy of different doses of vamorolone in boys with DMD, and compare the safety of vamorolone vs. glucocorticosteroids, prednisone or deflazacort in boys with DMD.

Methods

We performed systematic searches of the PubMed, Embase, and Cochrane Library databases for vamorolone, glucocorticosteroids, prednisone or deflazacort in boys with DMD. We assessed statistical heterogeneity across trials based on the Newcastle Ottawa scale (NOS) tool test and I2 values, and mean differences were pooled using the random-effects model. We used traditional meta-analysis to evaluate efficacy and safety of vamorolone 6.0 mg/kg/d vs. vamorolone 2.0 mg/kg/d and vamorolone vs. prednisone. A network meta-analysis was applied to estimated the safety of vamorolone in comparison to glucocorticosteroids, prednisone and deflazacort. Our meta-analysis were performed using Revman 5.4 software, and our network meta-analysis were performed using Stata/MP 18.0.

Results

In the meta-analysis, a total of 193 patients were analyzed across four clinical trials (97 patients receiving vamorolone 2 mg/kg per day; 96 patients receiving vamorolone 2 mg/kg per day). We observed that there were statistically significant differences in boys with DMD between vamorolone 6.0 mg/kg/d and vamorolone 2.0 mg/kg/d in TTSTANDV (MD = 0.03, 95%CI = 0.00-0.06, p = 0.04), TTRWV (MD = 0.13, 95%CI = 0.08-0.19, p < 0.01), 6MWT (MD = 24.54, 95%CI = 4.46-44.82, p = 0.02), TTCLIMBV (MD = 0.04, 95%CI = 0.01-0.06, p = 0.009), no significant difference in BMI z score (MD = 0.09, 95%CI = -0.03-0.20, p = 0.13). Indirect comparisons derived from network meta-analysis did not show significant differences among vamorolone, glucocorticosteroids, prednisone and deflazacort in BMI z score.

Conclusion

Our findings implied that boys with DMD who took vamorolone 6 mg/kg daily instead of 2 mg/kg daily may be safer and have superior motor function. However, more large sample randomized controlled trials are needed to confirm our results.

Systematic Review Registration

This systematic review and meta-analysis has been registered in the International Prospective Register of Ongoing Systematic Reviews PROSPERO (registration number: CRD42024562916).

Comparison of pharmaceutical properties and biological activities of prednisolone, deflazacort, and vamorolone in DMD disease models

Duchenne muscular dystrophy (DMD) is a progressive disabling X-linked recessive disorder that causes gradual and irreversible loss of muscle, resulting in early death. The corticosteroids prednisone/prednisolone and deflazacort are used to treat DMD as the standard of care; however, only deflazacort is FDA approved for DMD. The novel atypical corticosteroid vamorolone is being investigated for treatment of DMD. We compared the pharmaceutical properties as well as the efficacy and safety of the three corticosteroids across multiple doses in the B10-mdx DMD mouse model. Pharmacokinetic studies in the mouse and evaluation of p-glycoprotein (P-gP) efflux in a cellular system demonstrated that vamorolone is not a strong P-gp substrate resulting in measurable central nervous system (CNS) exposure in the mouse. In contrast, deflazacort and prednisolone are strong P-gp substrates. All three corticosteroids showed efficacy, but also side effects at efficacious doses. After dosing mdx mice for two weeks, all three corticosteroids induced changes in gene expression in the liver and the muscle, but prednisolone and vamorolone induced more changes in the brain than did deflazacort. Both prednisolone and vamorolone induced depression-like behavior. All three corticosteroids reduced endogenous corticosterone levels, increased glucose levels, and reduced osteocalcin levels. Using micro-computed tomography, femur bone density was decreased, reaching significance with prednisolone. The results of these studies indicate that efficacious doses of vamorolone, are associated with similar side effects as seen with other corticosteroids. Further, because vamorolone is not a strong P-gp substrate, vamorolone distributes into the CNS increasing the potential CNS side-effects.

An update on Becker muscular dystrophy

PURPOSE OF REVIEW

The purpose of this review is to summarise the recent developments in trial readiness, natural history studies, and interventional clinical trials for Becker muscular dystrophy (BMD).

RECENT FINDINGS

As several treatment concepts have claimed to convert patients with Duchenne muscular dystrophy (DMD) into a BMD phenotype, BMD itself has moved into the focus of clinical research. Natural history studies have helped to better characterize patients with BMD and the disease is now a target for interventional trials. In parallel, there have been advances in diagnostics and in the development of preclinical models.

SUMMARY

Despite increased collaborative efforts to improve trial readiness amongst patients with BMD, there is still a lack of long-term natural history data, and the broad spectrum of disease severity remains a challenge for well designed clinical trials.

Considering the Promise of Vamorolone for Treating Duchenne Muscular Dystrophy

This commentary provides an independent consideration of data related to the drug vamorolone (VBP15) as an alternative steroid proposed for treatment of Duchenne muscular dystrophy (DMD). Glucocorticoids such as prednisone and deflazacort have powerful anti-inflammatory benefits and are the standard of care for DMD, but their long-term use can result in severe adverse side effects; thus, vamorolone was designed as a unique dissociative steroidal anti-inflammatory drug, to retain efficacy and minimise these adverse effects. Extensive clinical trials (ongoing) have investigated the use of vamorolone for DMD, with two trials also for limb-girdle muscular dystrophies including dysferlinopathy (current), plus a variety of pre-clinical trials published. Vamorolone looks very promising, with similar efficacy and some reduced adverse effects (e.g., related to height) compared with other glucocorticoids, specifically prednisone/prednisolone, although it has not yet been directly compared with deflazacort. Of particular interest to clarify is the optimal clinical dose and other aspects of vamorolone that are proposed to provide additional benefits for membranes of dystrophic muscle: to stabilise and protect the sarcolemma from damage and enhance repair. The use of vamorolone (and other glucocorticoids) needs to be evaluated in terms of overall long-term efficacy and cost, and also in comparison with many candidate non-steroidal drugs with anti-inflammatory and other benefits for DMD.