Idera Pharmaceuticals has completed patient enrollment in its ILLUMINATE-301 registrational trail evaluating tilsotolimod in combination with ipilimumab in patients with anti-PD-1 refractory advanced melanoma.

The randomised, Phase III trial is designed to compare the effectiveness of intratumoral tilsotolimod in combination with ipilimumab and with ipilimumab alone.

It has a primary endpoint family of overall response rate (ORR) per RECIST v1.1 and overall survival (OS). Secondary endpoints include durable response rate, time to response, progression-free survival, patient-reported outcomes, and safety.

The ILLUMINATE-301 trial has enrolled 481 patients across 80 sites in 11 countries.

The ORR and other preliminary data from ILLUMINATE-301 are expected to be announced in the first quarter of next year.

Tilsotolimod is an investigational receptor 9 agonist. Its intratumoral injection is said to assist innate (Type-I IFN, antigen presentation) and adaptive (T cells) immune activation.

Tilsotolimod received both fast-track designation and orphan drug designation from the US Food and Drug Administration (FDA). The drug is currently being analysed in multiple tumour types in combination with multiple checkpoint inhibitors.

Idera Pharmaceuticals CEO Vincent Milano: “We are making outstanding progress in moving toward our goal of delivering tilsotolimod to the market in our lead indication for anti-PD-1 refractory advanced melanoma patients.

“We achieved this critical milestone earlier than anticipated, which we believe is truly a testament to the high unmet need facing these patients.”

American Cancer Society has estimated that almost 100,000 people in the US will be diagnosed with invasive melanoma this year.