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

Cuyamycin Molecule looks promising for Myotonic Dystrophy Treatment

A new study published shows that a small molecule (Potential new treatment) disrupted the long CTG repeats but left short repeats mostly alone.This was tested in mice that had myotonic dystrophy and seemed to work well.  Here is a piece form the journal about the impact of this study

                                                     Significance
Development of small-molecule lead medicines that potently and specifically modulate RNA function is challenging. We designed a small molecule that cleaves r(CUG)exp, the RNA repeat expansion that causes myotonic dystrophy type 1. In cells and in an animal model, the small-molecule cleaver specifically recognizes the 3-dimensional structure of r(CUG)exp, cleaving it more selectively among transcripts containing short, nonpathogenic r(CUG) repeats than an oligonucleotide that recognizes RNA sequence via Watson-Crick base pairing. The small molecule broadly relieves disease-associated phenotype in a mouse model. Thus, small molecules that recognize and cleave RNA structures should be

Cugamycin-Mouse-Model

Ionis Pharmaceuticals Pursuing More Potent Myotonic Dystrophy Drug

Recent information came to light that Ionis is still continuing pursue a drug for myotonic dystrophy. The first trial ended and was not successful. What we learned is that the team was impressed that progress was made. Rather than pursue this initial drug they may be switching to a new more highly improved drug. This makes sense as the cost to pursue a drug is high $$$$ and you want your best candidate forward.

International Scientist meeting of Myotonic Dystrophy Researchers in San Francisco Sept 5-9 2017

The IDMC meeting will be in San Fransisco this year. Make plans to attend the scientific sessions  or the meeting of the Myotonic Dystrophy foundation

Please save September 5th – 9th, 2017 for the IDMC-11 conference being held in San Francisco, California. If you are interested in receiving updates about IDMC-11, please sign up online at www.idmc11.org.

IDMC 11

Welcome to the IDMC website, home of the International Myotonic Dystrophy Consortium (IDMC, or International Dystrophia Myotonica Consortia). This site is dedicated to the community of scientists, physicians and health care providers who have taken up the fight against Myotonic Dystrophy, a progressive neuromuscular disease that effects people and families around the world.

Potential Myotonic Dystrophy Drug Fails! – Ionis Myotonic Dystrophy Drug fails to reach minimal therapeutic value

In a instant news email the Myotonic Dystrophy Foundation (MDF) released information that the Ionis Pharmaceutical Drug DMPK-2.5Rx research project has been canceled. The drug DMPK-2.5Rx did not work, and did not get the correct amount of therapeutic drugs into the cells of the patients with myotonic dystrophy. The company may still continue research on a more potent combination but the current trial is halted.

This is hard to hear news for the myotonic community. This is the second drug in development to fail. This new drug is part of a number of new generation of interest drugs  in trying to find a drug to treat the disease. There are still a number of drugs in development but the Ionis one was the most advanced. Perhaps the information in this trial will be of help to the other drugs in development.  For those in the late stages of the disease the length of time to find a treatment that is FDA approved in unlikely now.

There continues to be some “off label” treatments including erythromycin and some NSAIDS as well as Actinomycin-D but none have had any proven human effect.

More information below.

Ionis Pharmaceuticals Reports on
DMPKRx Phase 1/2 Clinical Trial

Ionis Pharmaceuticals recently concluded a Phase 1/2 clinical trial to evaluate IONIS-DMPK-2.5Rx in myotonic dystrophy patients. IONIS-DMPK-2.5Rx was designed to target the toxic DMPK RNA in muscle that is responsible for myotonia or muscle dysfunction in DM1 patients. The clinical trial used dose escalation to assess safety and explore biomarkers for target engagement in muscle biopsies.

Ionis reports that small but encouraging trends in biomarker and splicing changes were observed during the trial, and that this study provided a much better understanding of how future clinical trials and improved clinical endpoints may be used. However, drug levels measured in biopsy tissue from trial participants indicated that the amount of target engagement would not achieve the desired therapeutic benefit to treat this disease.

Without the desired drug levels in muscle, Ionis has decided not to advance IONIS-DMPK-2.5Rx. It will instead pursue the discovery of a more potent drug to target DMPK using new muscle-targeting LICA chemistry made at Ionis.

The company sincerely thanks everyone in the DM community that participated in the study – patients, caregivers and physicians, noting, “we are committed to the DM patient community and we hope to advance a new, more potent drug into development that will benefit people living with DM1.”

Ionis invites DM community members to submit questions regarding the above announcement via this email address. MDF will collect questions through January 12th and then work with Ionis to get answers out to the community as soon as possible.