The chronotherapy of cancers, discovered twenty years ago by the researcher Francis Lévi, is based on the principle that drug efficacy may double depending on the time of day they are administered. “In addition, it is at this optimal time that the drugs are also up to 5 times less toxic for the body”, specifies Inserm. This technique was however not completely developed because there are important differences in biological rhythm between the patients, difficult to establish.
The team led by Francis Lévi therefore sought to work on this aspect of chronotherapy. “If, for 50% of patients, the optimal time is the same, the remaining 50% are either early or late on that time,” they explain. To better understand these differences, the researchers studied the toxicity of an anticancer drug, irinotecan, depending on the time of administration in several groups of mice.
They concluded that the optimal time for better tolerance to treatment varies up to eight hours between groups of mice. Result: the researchers worked on a mathematical model to establish the precise time at which irinotecan is least toxic to the body.
The next step is to validate this model for other molecules used in chemotherapy. “Beyond the expression of genes, they would also like to find other physiological parameters linked to the biological clock allowing to predict the optimal time of treatment for each patient. This work should make it possible to increase the efficiency and tolerance of treatments, but also considerably improve the quality of life of patients, ”concludes Inserm.
