Idera Pharmaceuticals (IDRA) reported Sunday that 6 out of 9 melanoma patients, or 67%, experienced clear disease control when treated with IMO-2125, the company’s intratumorally-delivered Toll-like Receptor (TLR) 9 agonist, in combination with Bristol-Myers Squibb’s (BMY) Yervoy, or ipilimumab; overall response rate was 44%.
The company said that the data was positive and encouraging as majority of patients with solid tumors do not respond to anti-PD-1 therapy and the published response rate to ipilimumab alone in anti-PD-1 refractory melanoma is only 10%-13%. IMO-2125 in combination with ipilimumab is tolerable at all dose levels studied.
The final results were from the company’s dose-selection phase of an ongoing phase 1/2 trial which included 18 patients, all but one of whom had progressed on nivolumab or pembrolizumab. Patients were treated with up to 6 doses of intratumoral IMO-2125 at doses ranging from 4 to 32 mg, along with standard dosing of ipilimumab. No dose-limiting toxicities were seen and the maximum tolerated dose was not reached. No previously unreported immune-related toxicities were observed. The 8 mg IMO-2125 dose was selected for further development in combination with ipilimumab based upon acceptable safety, clinical activity, and evidence for target engagement on serial biopsies of the injected tumor and a distant (non-injected) metastasis.