In a new study, researchers have revealed details of the discovery of a new cancer drug that could be used to treat a range of cancer types, including some blood cancers and solid tumors.
The drug, called fadraciclib, is already being tested in early clinical trials targeting select hematological malignancies and solid tumors.
The research was conducted by scientists at The Institute of Cancer Research, London and elsewhere.
Fadraciclib is a leading dual inhibitor of two cancer-driving proteins from the cyclin-dependent kinase (CDK) family, CDK2 and CDK9.
It was designed by improving the chemical properties of a previous CDK inhibitor drug from Cyclacel, called seliciclib.
These structural design modifications led to a 20-fold more potent activity against the CDK2 and CDK9 targets and an equivalent 30-fold increase in therapeutic potency against a panel of human cancer cells, as well as a high degree of selectivity versus a wide range of 256 other protein kinases.
The researchers also provide clear evidence that CDK2 and CDK9 are inhibited in fadraciclib-treated cancer cells, leading to altered gene expression and cell death by apoptosis.
In the research, the team also did experiments in cells and mice that demonstrate fadraciclib’s potential as a treatment for leukemia.
They found that fadraciclib inhibited the growth of human acute myeloid leukemia tumors growing in immune-deprived mice by up to 100%.
A particularly important effect was a profound and sustained decrease in the levels of MCL1—a protein involved in cancer cell survival and drug resistance.
In the new paper, the researchers also found a link between sensitivity to fadraciclib and levels of the MCL1 and BCL2 proteins in cancer cells, and also the presence of ‘rearranged’ copies of a gene called MLL (mixed-lineage leukemia), which is often co-opted in blood cancers to drive the production of other cancer-causing proteins.
All of these factors could be tested in patients to help select those most likely to benefit from the drug, the scientists believe.
In addition to the promise in leukemia, the researchers observed beneficial activity for fadraciclib against human breast cancer cells.
This was again linked to a reduction in the expression of MCL1 and the important oncogene MYC.
Fadraciclib is currently undergoing Phase I clinical studies.
Fadraciclib is one of 20 drug candidates discovered by the scientists, of which 10 have entered clinical trials—making the team the most successful academic center in cancer drug discovery in the world.
The study is published in PLOS One.
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