An inhibitor of cyclin dependent kinase (CDK) originated by UK biopharmaceutical company Cyclacel has generated encouraging data in a Phase I trial.
The compound, called CYC202 (R-roscovitine) appears to induce cancer cells to undergo apoptosis, also known as programmed cell death, by acting on cell cycle regulators. It is hoped that this approach will stop uncontrolled cell division in cancer and other diseases involving abnormal cell proliferation.
The Phase I study used a novel biomarker developed specifically to detect cellular material release by cancer cells undergoing apoptosis. It also looked at plasma proteomic profiles before and after treatment with CYC202 in order to identify additional protein markers released in response to the drug.
The biomarker data revealed that out of 26 cancer patients treated with a single dose of the CDK inhibitor, 14 (56 per cent) tested positive for apoptosis using the assay. In addition, seven patients experienced long-lasting tumour stabilisation with CYC202 treatment.
Athos Gianella-Borradon, Cyclacel's medical director, said: "now that we have established a baseline for quantifying apoptosis in patients undergoing CYC202 monotherapy, we can use such biomarker techniques to assess the effects of the drug on patients receiving CYC202 in combination with chemotherapy."
Two Phase IIa trials looking at combination treatment in breast and lung cancer are already ongoing, and Cyclacel is also planning trials in patients with glomerulonephritis, a disease of renal cell proliferation.
The results of the biomarker trial were presented at the ongoing American Association of Cancer Research annual meeting in Washington DC.