US-based Rexahn Pharmaceuticals has conducted stage 2 of the Phase Ib/IIa clinical trial with the new oral anti-cancer agent RX-3117 in patients with relapsed or refractory pancreatic cancer.
RX-3117 is an investigational, small molecule nucleoside compound and once intracellularly activated (phosphorylated) by UCK2, it is incorporated into the DNA or RNA of cells and inhibits both DNA and RNA synthesis, which induces apoptotic cell death of tumour cells.
The company reported that the decision to proceed with the second stage was based on satisfying the predefined criteria for preliminary efficacy for stage 1 of the trial.
In the first stage of the trial, RX-3117 was safe and well-tolerated, with preliminary efficacy seen in pancreatic cancer patients for whom three prior therapies had been ineffective.
The ongoing multicentre, open-label, single-agent Phase Ib/IIa trial of RX-3117 is being conducted at ten clinical centres in the US.
Rexahn chief medical officer Ely Benaim said: "This data is very promising since there are no available treatments for pancreatic cancer patients who have failed three prior therapies.
"These patients would usually be offered palliative or best supportive care. Having 40% of patients showing responses beyond two months is certainly encouraging. I look forward to further evidence of benefit at the end of the trial."
In the trial patients receive a 700mg daily oral dose of RX-3117, five times weekly on a three weeks on, one week off dosing schedule in a 28 day cycle for up to eight treatment cycles, or until their disease progresses.
Around ten patients with relapsed or refractory metastatic pancreatic cancer were enrolled in the first stage of the trial, which follows a two-stage design.
The company noted that based on predefined criteria, if 20% or more of the patients had progression free survival of more than four months, or an objective clinical response rate and reduction in tumour size, then an additional 40 pancreatic cancer patients would be enrolled into the second stage.
Patients enrolled into the first stage of the trial had an actively progressing disease, with 44% of them having failed more than three prior cancer therapies.
Rexahn CEO Peter Suzdak said: "The initiation of stage 2 of the Phase Ib/IIa clinical trial in refractory metastatic pancreatic cancer marks a major milestone in the RX-3117 clinical development programme.
"Results from stage 1 of the Phase Ib/IIa clinical trial have been submitted for presentation at the European Society for Medical Oncology (ESMO) conference that will take place in October 2016."
The company had previously completed an exploratory Phase I trial of RX-3117 in cancer patients conducted in Europe, which evaluated the compound's oral bioavailability, safety and tolerability.
During the trial, oral administration of a 50mg dose of RX-3117 showed an oral bioavailability of 56% and a plasma half-life (T1/2) of 14 hours.