Translarna (Ataluren)

Translarna (ataluren) is an oral small-molecule treatment developed by PTC Therapeutics.

The therapy is approved — with conditions — in the European Union for ambulatory (able to walk) patients, 2 years and older, who have Duchenne muscular dystrophy (DMD). The treatment is also approved in Russia and Brazil, and is accessible to patients in the U.K. Translarna’s conditional approval in Europe means that more evidence is needed to attain full approval.

In 2020, the Committee for Medicinal Products for Human Use, part of the European Medicines Agency, recommended expanding the use of Translarna to DMD patients who lost their ability to walk.

In the U.S. however, the Food and Drug Administration rejected Translarna’s approval, stating that it is unable to approve the therapy due to the lack of substantial evidence of its effectiveness.

How Translarna works

DMD is an inherited progressive condition, characterized by gradual muscle weakening. Becker muscular dystrophy is a milder version of the disease. Both conditions are caused by a mutant (faulty) copy of the DMD gene, which codes for a protein called dystrophin that is essential to protect muscles from damage.

Symptoms of DMD can begin as early as age 2. As the disease progresses, patients will find activities such as walking increasingly more difficult, and may develop scoliosis (a sideways curvature of the spine), contractures — when muscles become shortened, restricting movement of the joints — as well as digestive, respiratory, and cardiac problems.

Translarna is designed to treat patients who have a particular type of defect in the DMD gene called a nonsense mutation.

A nonsense mutation introduces a stop signal in the gene that causes the synthesis of the dystrophin protein to stop prematurely. This results in a truncated protein that cannot function normally and is subsequently destroyed by the cell. Up to 15% of DMD cases are caused by this type of mutation.

Translarna forces the cell to ignore this abnormal stop signal, enabling the production of the full-length, functional protein. Thus, Translarna works as a “protein restoration therapy,” which means that it aims to facilitate the production of a functional protein in patients who cannot produce it normally.

Translarna in clinical trials

Translarna was tested in a randomized, double-blind Phase 2b study (NCT00592553) conducted in 11 countries to assess the treatment’s safety, dosage, and efficacy in males (5 years or older) with DMD caused by nonsense mutations.

Results at 48 weeks showed that the treatment was generally well-tolerated and led to increases in the distance walked in six minutes, a standard test of functional capacity, compared to a placebo. Statistically significant benefits were found in timed function tests, such as the 10-meter run/walk test, the 4-stair climbing test, and the ability to stand when lying on the back or with the face upward.

STRIDE — an ongoing observational global study (NCT02369731) — is following patients treated with Translarna, plus standard care (including corticosteroids), for at least five years. It’s being conducted in partnership with the neuromuscular network TREAT-NMD, and is currently recruiting participants.

Data from this study showed that Translarna delayed the loss of walking abilities by more than five years in DMD boys with nonsense mutations, compared to those on standard treatment alone. In the treated boys, lung function decline was slowed by nearly two years. The treatment has been well-tolerated, with adverse events consistent with the medication’s known safety profile.

The long-term effects of Translarna on walking abilities is being assessed in a placebo-controlled Phase 3 trial (NCT03179631) in 360 males, 5 and older, who can walk. The 72-week treatment period (about 1.4 years) is followed by an open-label period of the same duration in which all participants receive Translarna.

Other information

Translarna is available in sachets of 125, 250, and 1,000 mg. The treatment is taken orally after mixing it in liquid or in semi-solid food such as yogurt.

The therapy is to be taken three times a day. The recommended dose is 10 mg (per kg of body weight) in the morning and at midday, and 20 mg/kg in the evening. The total recommended daily dose is 40 mg/kg. Recommended dosing intervals are six hours between morning and midday doses, six hours between midday and evening doses, and 12 hours between the evening dose and the dose the following morning.

The most common side effects of Translarna in clinical trials were vomiting, diarrhea, nausea, headache, upper abdominal pain, and flatulence.

Translarna is contraindicated in patients who have had allergic reactions to ataluren or to any ingredient in the treatment. Patients should not take Translarna alongside intravenous (into the vein) aminoglycosides, a class of antibiotics.

Patients with severe kidney impairment should only start treatment with Translarna if the anticipated clinical benefit outweighs the potential risk, and should be closely monitored to assess the treatment’s toxicity and possible decrease in efficacy. Patients should also be monitored for changes in blood levels of lipids (fats).

More information may be found on the treatment’s summary of product characteristics.

 

Last updated: Feb. 23, 2022, by Teresa Carvalho MS

 


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