Mirna Therapeutics this week announced interim data from its ongoing Phase I trial of MRX34, a microRNA mimic designed to treat cancer, which showed the drug to have a "manageable safety profile."
According to the company, an interim analysis of 26 patients with unresectable primary hepatocellular carcinoma (HCC) or solid tumors with liver involvement revealed a single incident of a dose-limiting toxicity. Other treatment-related adverse events consisted primarily of infusion reactions.
The data were presented at this year's American Association for Cancer Research annual meeting.
Given these data, the company is on track to begin Phase II testing, most likely in HCC patients, around the middle of 2015, Mirna President and CEO Paul Lammers said.
MRX34 is a synthetic version of miR-34a, an miRNA known to play a key role in the p53 tumor-suppressor pathway. Mirna has also said that its own work indicates that miR-34a represses the expression of more than 20 oncogenes and inhibits processes required for cancer cell viability, cancer stemness, metastasis, and chemoresistance.
Formulated with Marina Biotech's Smarticle liposomal delivery technology, the agent entered the clinic in mid-2013, making it the first miRNA mimetic to be tested in humans. That study is evaluating escalating intravenous doses of MRX34 in around 30 patients with either primary HCC or advanced solid tumors with liver involvement.
After finding the compound's maximum tolerated dose, Mirna had originally anticipated enrolling an additional 18 patients with select tumors into the trial to test MRX34's efficacy outside the liver.
But according to Lammers, that expansion arm will now likely enroll only HCC patients.
"We feel that HCC provides a great opportunity to show clinical [proof of concept] for MRX34 based on our preclinical data, as well as the high unmet need in this very difficult to treat cancer type," he told Gene Silencing News.
He also noted that 29 patients have now been enrolled in the trial, and that study investigators have yet to reach MRX34's maximum tolerated dose.