Since the appearance of SARS-CoV-2, researchers have looked at therapeutic repositioning strategies. Concretely, they have tested drugs already authorized for other indications, to determine if they could have beneficial effects against Covid-19. It is in this context that debates have arisen around hydroxychloroquine, without the numerous clinical data available to date really confirming the therapeutic interest of this molecule used in the management of lupus erythematosus or of rheumatoid arthritis. For a few days it has been another treatment, plitidepsin, which is talking about him.
A medicine used in the treatment of multiple myeloma
Scientists from the Quantitative Bioscience Institute, UC San Francisco and the Icahn School of Medicine at Mt.Sinai have indeed shown that plitidepsin, a drug approved by the Australian Regulatory Agency for the treatment of multiple myeloma (a type of blood cancer), has a powerful antiviral activity against SARS-CoV-2. It has currently only been the subject of a phase I / II clinical study, but the first results published in the journal Science indicate that it is 27.5 times more potent against SARS-CoV-2 in vitro than remdesivir, an antiviral that received in 2020 an emergency use authorization from the FDA (United States Medicines Agency) for the treatment of COVID-19.
A phase III study soon to be launched
This drug was developed by the Spanish company Pharmamar, which affirms in a press release that “the data and the first positive results of the clinical trial suggest than plitidepsin should be strongly considered for expanded clinical trials for the treatment of COVID-19. She says she is in talks with regulators to start phase III trials. Plitidepsin works by blocking the eEF1A protein present in human cells and of which SARS-CoV-2 is used to reproduce and infect other cells. This inhibition prevents its reproduction inside the cell, limiting its spread in the body.
The study carried out in vitro and in vivo also showed that the drug leads to a strong reduction in viral replication, resulting in a 99% reduction in viral load in the lungs of mice treated with plitidepsin. The researchers also tested the synergy between plitidepsin and remdesivir in vitro, and the data show that plitidepsin has an additive effect with remdesivir, which would make it a potential drug candidate to consider for combination therapy. Knowing however, in France the HCSP considers that, “After analysis of the data in the literature available as of May 31, 2020 on the efficacy and safety of use of remdesivir for the treatment of patients with Covid-19, that they are insufficient to estimate a benefit / risk ratio of this treatment according to the severity of the Covid-19. ”
“Plitidepsin is a extremely potent SARS-CoV-2 inhibitor, but its most important strength is that it targets a host protein rather than a viral protein, ”explains Prof. Kris White of the Icahn School of Medicine at Mount Sinai. “This means that if plitidepsin is successful in treating COVID-19, the virus will not be able to gain resistance against this drug by mutation, which is a major concern with the spread of the British and South African variants.” Another study should confirm this, but if SARS-CoV-2 and its variants use the same “infection route”, this means that they could be sensitive to the same molecules inhibiting this virus-host interaction. The Spanish pharmaceutical company first isolated this molecule (under the trade name “Aplidin”) from a marine organism known as “Aplidium albicans.” ”
To find out more about the coronavirus, the editorial staff invites you to discover its more complete and regularly updated articles:
- an article on Covid-19 disease and the evolution of the epidemic
- an article on the different screening tests
- an article on vaccines under development.