Drug repurposing shows promise in the treatment of inherited retinal degenerations (IRDs), according to a new study, published in Nature Communications.1
The researchers found that a combination treatment incorporating three existing drugs – tamsulosin, metoprolol, and bromocriptine – slowed disease progression in pre-clinical retinopathy models.
Drug repurposing refers to the use of existing drugs to treat diseases or conditions that they were not originally developed or approved for. The most significant advantages of drug repurposing can be found in faster drug development times and lower costs. Since repurposed drugs have already undergone several mandatory safety tests and early stages of clinical trials, their market entry is considerably faster and cheaper than that of completely new drugs.
The new study focussed on drug repurposing in the context of IRDs. IRDs are a group of genetic diseases that cause the deterioration of retinal anatomy and function, leading to gradual loss of vision and often blindness.
The researchers found that a combination treatment incorporating the three drugs significantly slowed disease progression and decreased disease manifestation in four different animal models of IRD.
The combination included the blood pressure and heart failure drug metoprolol; tamsulosin, which is used for the treatment of benign prostatic hyperplasia; and bromocriptine, a Parkinson’s disease drug.
“In drug repurposing, it does not matter to which diseases or conditions the drugs were originally developed for, but it is the molecular-level effects of drugs, or pharmacology, that count,” said the article’s first author Dr Henri Leinonen in a news release.2
“We hypothesised that the combined effect of these drugs would alleviate the disease, which it indeed did in several distinct animal models of IRDs.”
But he said that the efficacy and safety of this combination in humans with retinal degeneration is not guaranteed and noted that further controlled clinical trials are needed.
It is noteworthy that none of the drugs used in the study were effective against retinal degeneration on their own; instead, their combination was necessary for efficacy.
References
- Leinonen H, Zhang J, Occelli LM et al. A combination treatment based on drug repurposing demonstrates mutation-agnostic efficacy in pre-clinical retinopathy models. Nat Commun 15, 5943 (2024). doi: 10.1038/s41467-024-50033-5.
- University of Eastern Finland, Combination treatment based on drug repurposing shows promise in the treatment of retinal degenerations (media release, 22 July 2024), available at: eurekalert.org/news-releases/1052081 [accessed 23 July 2024].