NEW YORK – Cyclacel Pharmaceuticals said on Tuesday that it has dosed the first patient in a Phase I/II trial of its CDK2/9 inhibitor fadraciclib, in which it is exploring the activity of the drug in solid tumors or lymphomas.
In the first phase of the multi-cohort, registration-directed trial, investigators will determine the recommended Phase II dose for single-agent, oral fadraciclib. Then, the trial will advance to its Phase II portion, at which time patients will be stratified into up to eight cohorts according to tumor type.
These cohorts will include breast, colorectal, endometrial, hepatocellular, and ovarian cancers as well as certain lymphomas. The breast cancer cohort will include patients with metastatic, hormone receptor-positive, HER2-negative breast cancer patients whose cancers have progressed following treatment with a CDK4/6 inhibitor as well as patients who are refractory to HER2-targeting treatment and patients with triple-negative breast cancer. Beyond the histology-defined cohorts, the trial will also include a tumor-agnostic cohort consisting of patients with MCL1- or MYC- or cyclin E-amplified cancers.
Berkeley Heights, New Jersey-based Cyclacel is evaluating biomarkers in the Phase I/II trial based on results of a prior Phase I trial, in which patients with high copy cyclin E, MYC, or MCL1 were particularly sensitive to fadraciclib. During this trial, one patient with MCL1-amplified endometrial cancer experienced a partial response to fadraciclib after a month of treatment and then saw a complete reduction in tumor size over two years of treatment. Another patient with cyclin E-amplified ovarian cancer experienced a 29 percent reduction in target tumor size.
The Phase I/II trial is initially enrolling patients at City of Hope and MD Anderson Cancer Center but will expand to additional locations. The trial is also designed to allow for cohort expansion and facilitate Cyclacel's registration plans for fadraciclib.
According to Cyclacel CEO Spiro Rombotis, the study is the first of four Phase I/II trials the firm plans to launch in the coming months as it focuses on evaluating fadraciclib, as well as its oral PLK1 inhibitor CYC140 in solid tumors, lymphomas, and leukemias.