Idera: Idera Pharmaceuticals' stock tanks after AbbVie cuts enrollment early in a PhIb trial

When Idera Pharmaceuticals flunked a Phase III melanoma trial with its Toll-like receptor 9 agonist tilsotolimod back in March, executives clung to the hope that separate trials in other cancers would turn up better results. Without the results it was hoping for, Idera says it's now discontinuing enrollment in a key Phase II study and considering out-licensing the candidate. AbbVie's also cutting recruitment short in an earlier-stage partnered study - causing Idera's stock $IDRA, already worth less than a $1, to tank more than 27% on Wednesday afternoon. "While our clinical trials with tilsotolimod have not yet translated into a new treatment alternative for patients, data supporting tilsotolimod's mechanism of action and encouraging safety profile from across the array of pre-clinical and clinical work to date, together with its intellectual property protection, are noteworthy," CEO Vincent Milano said in a statement. "As a result, we will consider an out-licensing arrangement for tilsotolimod so that its full potential may continue to be explored on behalf of patients who do not respond to traditional immunotherapy," he added. The first set of bad news on Wednesday came from the second 10 patients in the safety cohort of ILLUMINATE-206, a Phase II trial testing tilsotolimod in combination with Bristol Myers Squibb's Opdivo and Yervoy in microsatellite-stable colorectal cancer. Of eight patients who had a post-baseline disease assessment, only one saw stable disease, and the rest saw progression of their cancer, Idera said. However, that includes one patient who experienced a pseudo-progression, meaning that the initial increase from baseline in tumor burden was followed by a decrease, which is considered an immune-related partial response on another scale. Idera says it won't enroll any more patients in ILLUMINATE-206. According to clinical trials.gov, the study was supposed to enroll 30 patients total. Enrollment is also being discontinued in an AbbVie-sponsored trial for recurrent or metastatic head and neck squamous cell carcinoma, looking at tilsotolimod in several combinations with AbbVie candidates. The Phase Ib study, which was announced back in 2019, was testing three separate arms: An OX40 agonist called ABBV-368 plus tilsotolimod; ABBV-368 plus tilsotolimod and chemotherapy (nab-paclitaxel); and ABBV-368 plus tilsotolimod, nab-paclitaxel and a PD-1 antagonist called ABBV-181. Idera says the discontinuation "was not related to safety concerns," and that current treatment and follow-up is ongoing. AbbVie wasn't available for comment as of press time. This isn't the first time a Big Pharma partnership with tilsotolimod didn't work out. Back in May, Bristol Myers Squibb said it wouldn't finish a trial assessing tilsotolimod in combination with ipilimumab versus ipilimumab alone in patients with anti-PD-1 refractory advanced melanoma. "Our conclusion is that the totality of the data, with all patients having completed the study treatment, does not support the likelihood that the combination of tilsotolimod with ipilimumab would achieve a statistically significant OS benefit over ipilimumab alone," Milano said in a statement at the time. According to Idera's website, it appears that tilsotolimod is the only candidate in the company's pipeline. The company says there are still two investigator-sponsored studies of tilsotolimod ongoing at the VU University Medical Center (VUmc) Amsterdam and the Gustave Roussy Cancer Campus in Paris, as a monotherapy in melanoma and a combination therapy with Opdivo and Yervoy in advanced cancers, respectively. "We also continue both to preserve cash and to identify and explore potential development or commercial-stage assets for Idera's portfolio, and we are encouraged by the opportunities presented to us," Milano said.