New Drug Combo Study Helps Push back Myotonic Dystrophy in Mice

A recently published article used a combination of erythromycin and the prodrug of furamidine (pafuramidine) orally administed to mice that had Myotonic Dystrophy. This combination help with the problems that DM causes in the cells. A promising potential therapy however with some limitations.

Already a study back in 2014 showed that Erythromycin an FDA approved drug can help with a therapeutic approach to the disease in Mice. Many individuals have also taken this FDA approved drug to help with the myotonic dystrophy disease.

The new combination involves combination of erythromycin and the prodrug of furamidine (pafuramidine), The second drug pafuramidine is not available yet. It was studied in a phase III study for African sleeping sickness but not easily commercially available. The drug was found effective for African Sleeping sickenss. It looked very promising with a phase 3 study in many countries in Africa.  However, the phase I testing in healthy volunteers there was a possible adverse reaction to pafuramidine casing renal issues in 2 of 175 healthy volunteers (1.1%) . Looking more deeply into the adverse reaction there were 2 individuals with serious reactions including one that required dialysis as a probably result of the drug pafuramidine.  As such the drug was not further pursed. In the study in Mice with myotonic dystrophy the amount of pafuramidine was 5X lower than what was used in humans for African sleeping sickness so potentially much safer. There is some research into other analogs (Variations) of pafuramidine for future studies.

Th study still shows that erythromycin can be potentiated (enhanced) by other drugs but this combo seems to dangerous to use in humans due to the kidney reactions in a small group. Its small but the drug seemed to seriously degrade the urinary system

Here is some information on the study:

In DM1 patient-derived myotubes, the rescue of mis-splicing was observed with little to no celltoxicity. In a DM1 mouse model, a combination of erythromycin and the prodrug of furamidine (pafuramidine), administered orally, displayed both additive and synergistic mis-splicing rescue. Gene expression was only modestly affected, and over 40% of
the genes showing significant expression changes were rescued back toward WT expression levels. Further, the combination treatment partially rescued the myotonia phenotype in the DM1 mouse. This combination treatment showed a high degree of
mis-splicing rescue coupled with low off-target gene expression changes. These results indicate that combination therapies are a promising therapeutic approach for DM1. But the exact Drug pafuraminde has a severe adverse reaction so it can not be used now. Perhaps other drugs that potentiate erythromycin can be used in the future.

 

Combination-Therapy-Erythromycin-and-Furamidine

Below is the supporting information including the instructions for making the second drug pafurmidine

Synthesis-scheme-for-pafuramidine-manufacturing

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Combination Drugs May be More Effective in Treating Myotonic Dystrophy

A recent review study suggested that combination therapies may be the most optimal pathway to treat myotonic dystrophy. A few years ago when the defective pathway for myotonic dystrophy was identified it was proposed that treatment would be easy to find as it was proposed that the clumping would be easy to defeat. This has proven not to be the case. Here is a summary from the study:

One potential strategy is a combination approach (e.g., di erent small molecule
combinations, small molecules plus ASOs, transcription inhibition plus RAN protein ablation, etc.)targeting multiple processes and allowing synergy in disease modulation. As proof of concept, a recent study reported that two previously characterized compounds that separately displayed ecacyin DM1 models, furamidine and erythromycin, displayed an even greater rescue of mis-splicing in
combination than expected from a mere additive e ect [110]. Importantly, this combination treatment yielded lower toxicity and fewer o -target e ects than when either drug was administered alone inDM1 patient and mouse models [110]. Hence, if combination treatments are a viable therapeutic strategy for treating DM, there are already many unexplored therapeutic avenues that could potentially hold promise. Given the number of small molecule therapies for DM on the horizon, it will be exciting
to follow their development. These studies will lay the groundwork for the eventual therapies for treating DM and will likely illuminate disease biology and treatment avenues for other microsatellite expansion disorders involving toxic RNA mechanisms.

 

Review-of-Drug-Therapies-for-myotonic-Dystrophy

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Exercise May help Strengthen Muscles in Myotonic Dystrophy

A new study ( But only of two people) shows that it is possible to increase muscle strength in Myotonic Dsytrophy. This study seemed to show that the exercise program needs to be adopted to the individual so that they maintain the exercise program. The Muscle strength increase seems to be linked to how diligent the person followed the training regime. From the Study:

Our results suggest that muscular adaptations linked to muscle growth can occur in DM1 as demonstrated by the CSA increase of type I and type II myofibers. Training might also influence the distribution of myofibers, in favour of type II. The myogenic and inflammatory markers evaluated do not seem to be modulated by the training stimulus in our participants. Compliance to the program seems to be an important factor to consider. Patient’s preferences regarding training regimen should be considered in the perspective of personalized training/precision medicine. It should be noted that beyond the positive impact of training on muscle adaptations, it could also bring positive changes in other organ systems. Further studies comprising a higher number of participants and controls are needed to validate our findings and determine to which extent and how skeletal muscles of DM1 patients adapt to strength training.

Excercise-Training-Program-DM1

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MDA Invests 550K into San Diego Therapy Company

MDA Awards Locana $550K to Advance Potential RNA-targeting Therapy for Myotonic Dystrophy

Locana Logo

 
MDA Awards Locana $550K to Advance Potential RNA-targeting Therapy for Myotonic Dystrophy
 

The Muscular Dystrophy Association (MDA) has awarded Locana $550,000 through its MDA Venture Philanthropy (MVP) program to help advance the biotech company’s therapy platform for myotonic dystrophy (DM).

Specifically, the grant to the San Diego, California-based gene therapy company is aimed at furthering the development of its RNA-targeting technology.

“We’ve witnessed incredible innovation with the development of the first FDA-approved gene therapy for a neuromuscular disease,” Lynn O’Connor Vos, the MDA’s president and chief executive officer, said in a news release. She was speaking in reference to Zolgensma (AveXis and Novartis), approved May 24 by the U.S. Food and Drug Administration to treat spinal muscular atrophy.

“This gives us hope that novel approaches — such as Locana’s for designing highly specific RNA-targeting candidates — for treatment of myotonic dystrophy can address the significant unmet needs for patients who live with this genetic disease.”

The project’s chief investigator will be Ranjan Batra, Locana’s vice president of research and development.

“We appreciate the support of MDA to address this devastating disease,” said Jeffrey M. Ostrove, PhD, Locana chief executive officer. “DM is caused by expression of dysfunctional, repetitive RNA in diseased tissues, where application of Locana’s core RNA-targeting technology has been shown to have  potential for single-dose benefit, and could provide a long-lasting approach for patients.”

Estimated to affect one in 8,000 individuals globally, myotonic dystrophy is the most common adult-onset form of muscular dystrophy (MD) and has two types, both caused by genetic mutations. DM1 results from an abnormal expansion in a region of the DMPK gene. DM2 is caused by an expansion in the CNBP gene.

Locana is using its gene-editing CRISPR/Cas9 technology to target disorders, including DM and Huntington’s disease, caused by abnormally repeated genetic sequences.

With this monetary support, the MDA is hoping to build upon work detailed in proof-of-concept studies published the journal Cell in 2017. Those efforts involved researchers, including founding officers of Locana, that used CRISPR to edit RNA originating from mutations responsible for myotonic dystrophy. Scientists were able to successfully edit the faulty RNA in muscle cells of those with DM and related diseases, as well as reverse hallmark features of disease.

Producing RNA-targeting molecules could lead to enduring effects, the company said. That means the therapy might need to be administered just once.

The strategy is distinct from DNA-targeted approaches, as well as from nucleic acid-based RNA targeting. Its overarching goal is to produce a portfolio of treatments that address the primary cause of genetic diseases caused by the actions of dysfunctional RNA.

“Mutations in our DNA can cause disease, and our RNA-targeting technology platform allows us to precisely address these mutations,” Locana states on its website. “By targeting RNA, our approach avoids the risk of off-target effects in DNA.”

MVP, the MDA’s drug development program, is solely focused on funding the discovery and clinical application of treatments and cures for neuromuscular diseases.

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French Myotonic Dystrophy Registry

A new article gives good information on the breakdown of DM1 in the French population. 

Fig. 3 Cartography of place of residence of enrolled DM participants. a The individual representation (N = 2875). Each dot refers to one patient
place of residence and dots position is allocated to a random position in the corresponding department (top left). b The regional distribution
according to the density of population (N = 2875). Darker the green is, more the DM is prevalent in the department (top right). c Distribution of
DM-Scope Registry enrolled patients among paediatric French neuromuscular expert centres (26 centres, N = 255). The number of enrolled
patients is spot-size dependent (bottom left). d Distribution of DM-Scope Registry enrolled patients among adult French neuromuscular expert
centres (29 centres, N = 2620). The number of enrolled patients is spot-size dependent (bottom right)
French-Registry-article-dm1-myotonic-dystrophy

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