Hanmi Pharmaceuticals and Kinex Pharmaceuticals recently announced preliminary findings from a Phase I clinical trial of Oratecan, an oral formulation of irinotecan (Camptosar), an already-approved intravenous treatment for colon cancer.
The oral form employs a specific and potent gastrointestinal P-glycoprotein inhibitor called HM30181, as opposed to the intravenous type 1 DNA topoisomerase inhibitor.
Prior to this study, two collaborative research efforts determined Oratecan’s maximum tolerated dose (MTD) when administered alone to be 20mg/m2 when given on days 1-5 in a 21-day cycle, and 10mg/m2 on days 1-5 and 8-12 in a similar cycle. Now, the HM-OTE-103 study entitled, “A Phase I Clinical Trial to Determine the Maximum Tolerated Dose and to Assess the Safety of Oratecan in Combination with Capecitabine in Patients with Advanced Solid Cancer”, had both drug developers working on determining the MTD of Oratecan when administered with Capecitabine in a 21-day cycle.
There were a total of 21 participants enrolled in the drug study. The first portion involved administering Capecitabine at 800mg/m2 twice a day for 2 weeks. Oratecan was then given on days 1-5 at 10, 15, or 12mg/m2. The second portion of the study administered Capecitabine at 1000mg/m2 twice a day in combination with Oratecan at 15mg/m2. The results showed Oratecan’s MTD to be 15mg/m2, and capecitabine’s to be 1000mg/m2 twice daily.
The researchers then performed an efficacy evaluation on the participants who received at least one dose of the two drugs, observing that two subjects showed a partial response, eight showed stable disease, and another eight showed progressive disease.
Dr. Jeewoong Son, Hanmi Pharmaceuticals’ Chief Medical Officer, stated in a Hamni press release that these results confirm the compatibility of the Orascovery platform with a second drug. While they only intended to determine the MTD of these drugs, they were pleased to note a good number of participants exhibited stable disease, thereby strengthening the concept of platform technology.
Dr. Rudolf Kwan, the Chief Medical Officer at Kinex Pharmaceuticals, confirmed these new findings will serve as the basis of an upcoming clinical study that will seek to refine the optimal dosing of Irinotecan, which is set to start in 3 US clinical sites within the 4th quarter of 2014.
“The convenience of an oral formulation of Irinotecan means a lot to patients can avoid lengthy infusions. Oral drugs may also provide an opportunity for long term maintenance therapy”, Dr. Wing Kai Chan, Kinex Vice President for Clinical Operations, Asia Pacific concluded in the press release.