Redx said it communicated with the Medicines and Healthcare products Regulatory Agency (MHRA) to interrupt the clinical trial of the Porcupine inhibitor.
The company detected significant adverse events when the first patient has been dosed with the Porcupine inhibitor in the trial.
Redx, along with academic colleagues, thought that adverse events are the result of RXC004 on-target effects and Wnt pathway inhibition.
Analysis from the first patient showed that their systemic RXC004 exposure was significantly higher than that anticipated from preclinical studies.
RXC004 is a novel, oral and potent small molecule that targets the Wnt pathway, an embryonic signalling pathway that is involved in the maintenance of cancer stem cells in multiple cancer types.
The pathway is linked with tumorigenesis, metastasis, recurrence and resistance in cancer.
The first-in-man clinical trial of RXC004 is a modular, multi-arm, multi-part and adaptive design study designed to evaluate the safety and tolerability of the drug in patients with advanced malignancies.
Redx is planning to recruit 50 patients in the phase 1/2a clinical study.
According to the company, patients are allocated to a dose in the first phase and followed for a period time for potential dose limiting toxicities.
Once the first phase completes, the next arm of the study will be started with higher dosing until a maximum tolerated dose is reached.
Redx Pharma chief medical officer Dr Andrew Saunders said: “It is our current intention to propose a protocol amendment that enables dose-escalation to re-start at significantly lower dose levels.
“This protocol amendment will be finalised with consultation with both the MHRA and principal investigators.”
Redx Pharma executive chairman Iain Ross said: “The Board continues to believe the overall risk/benefit assessment of RXC004 as an investigational drug is unchanged.”