RESUMEN
During the last decade, a plethora of novel therapies containing live microorganisms as active substance(s) has emerged with the aim to treat, prevent, or cure diseases in human beings. Both the Food and Drug Administration (FDA) and the European Directorate for the Quality of Medicines and Health Care (EDQM) codified these biotherapies as Live Biotherapeutic Products (LBPs). While these innovative products offer healthcare opportunities, they also represent a challenge for developers who need to set the most suitable designs for non-clinical and clinical studies in order to demonstrate a positive benefit/risk ratio through relevant quality, safety, and efficacy data that are expected by the drug competent authorities. This article describes how YSOPIA Bioscience, supported by the Pharmabiotic Research Institute (PRI), addressed the regulatory challenges during the early development phase of their single-strain LBP, Xla1, in order to obtain the necessary authorizations to bring this drug to the clinical stage.
RESUMEN
Antimalarial drug resistance has historically arisen through convergent de novo mutations in Plasmodium falciparum parasite populations in Southeast Asia and South America. For the past decade in Southeast Asia, artemisinins, the core component of first-line antimalarial therapies, have experienced delayed parasite clearance associated with several pfk13 mutations, primarily C580Y. We report that mutant pfk13 has emerged independently in Guyana, with genome analysis indicating an evolutionary origin distinct from Southeast Asia. Pfk13 C580Y parasites were observed in 1.6% (14/854) of samples collected in Guyana in 2016-2017. Introducing pfk13 C580Y or R539T mutations by gene editing into local parasites conferred high levels of in vitro artemisinin resistance. In vitro growth competition assays revealed a fitness cost associated with these pfk13 variants, potentially explaining why these resistance alleles have not increased in frequency more quickly in South America. These data place local malaria control efforts at risk in the Guiana Shield.
All recommended treatments against malaria include a drug called artemisinin or some of its derivatives. However, there are concerns that Plasmodium falciparum, the parasite that causes most cases of malaria, will eventually develop widespread resistance to the drug. A strain of P. falciparum partially resistant to artemisinin was seen in Cambodia in 2008, and it has since spread across Southeast Asia. The resistance appears to be frequently linked to a mutation known as pfk13 C580Y. Southeast Asia and Amazonia are considered to be hotspots for antimalarial drug resistance, and the pfk13 C580Y mutation was detected in the South American country of Guyana in 2010. To examine whether the mutation was still circulating in this part of the world, Mathieu et al. collected and analyzed 854 samples across Guyana between 2016 and 2017. Overall, 1.6% of the samples had the pfk13 C580Y mutation, but this number was as high as 8.8% in one region. Further analyses revealed that the mutation in Guyana had not spread from Southeast Asia, but that it had occurred in Amazonia independently. To better understand the impact of the pfk13 C580Y mutation, Mathieu et al. introduced this genetic change into non-resistant parasites from a country neighbouring Guyana. As expected, the mutation made P. falciparum highly resistant to artemisinin, but it also slowed the growth rate of the parasite. This disadvantage may explain why the mutation has not spread more rapidly through Guyana in recent years. Artemisinin and its derivatives are always associated with other antimalarial drugs to slow the development of resistance; there are concerns that reduced susceptibility to artemisinin leads to the parasites becoming resistant to the partner drugs. Further research is needed to evaluate how the pfk13 C580Y mutation affects the parasite's response to the typical combination of drugs that are given to patients.