Conventional hemotoxicity, bone marrow toxicity also called myelotoxicity, is usually part of the toxicity checklist performed during the pre-clinical animal testing stage of drug development. This is when at least 2 different mammalian species are used to test one or more lead drug candidates so that information can be obtained which might indicate or predict the dose and effect in human subjects.
Conventional hemotoxicity testing usually consists of measuring a number of circulating blood cell parameters as well as looking at bone marrow morphology to ascertain whether abnormal cells are present as a result of drug administration.
With the exception of anti-cancer, anti-inflammatory and even anti-viral drugs, conventional hemotoxicity testing is considered to have a low priority compared to other toxicities such as neurotoxicity, liver toxicity, etc. Even then, hemotoxicity of many anti-cancer drugs is assumed to be an acceptable risk because, from the mechanism of action of the drug, it will be known that the agent will probably affect normal blood-forming stem and progenitor cells as well as the tumor cells.
However, there is a good chance that if a drug affects proliferating and dividing cells, the effect is not going to be on the circulating cells, but on those cells that give rise to the circulating cells. These are the all-important stem and progenitor cells of the blood-forming system. Damage to these cells takes time to become amplified so that the effects can be observed in the circulation as anemia, neutropenia, thrombocytopenia etc. If only the circulating blood-parameters are measured, it follows that the effects of a potentially toxic drug cannot be predicted until the response is seen in the circulation. Thus, conventional hemotoxicity testing has little, if any, predictive value.
Even the monitoring value of measuring the circulating blood parameters during clinical trials, once a drug has been approved, has questionable value because potentially harmful effects to the patient may have already occurred prior to observing any changes in the circulation.
HemoGenix® understood that conventional hemotoxicity testing, as provided by the guidelines of the regulatory agencies, was insufficient to provide adequate safety for the patient as far as hemotoxicity was concerned. As a result, faster, more reliable and sensitive assays were developed. The first of these was HALO®, followed by LUMENESC™ and LumiSTEM™.