Despite “encouraging” new data, iTeos Therapeutics is dropping a midstage cancer asset to focus on other programs, a move that will bring the biotech's clinical pipeline down to two investigational meds.
The immune checkpoint inhibitor therapy, dubbed inupadenant, didn’t meet iTeos’ scientific and clinical advisory boards’ bar to warrant further investment, iTeos CEO Michel Detheux, Ph.D., said in a Dec. 12 release. Given the deprioritization, iTeos will not be moving forward with a randomized, controlled portion of a phase 2 study assessing the candidate, a company spokesperson told Fierce Biotech.
The release largely focuses on inupadenant data that are being presented at the European Society for Medical Oncology Immuno-Oncology Congress 2024, with only two brief mentions about the discontinuation.
The data include an interim look at the dose-escalation portion of a phase 2 trial assessing the adenosine A2A receptor antagonist among patients with post-immunotherapy metastatic non-small cell lung cancer (NSCLC). The asset was being studied in combination with chemotherapy.
The combo showed a 63.9% overall response rate (ORR) and a median progression-free survival of 7.7 months for 36 evaluable patients across the cohorts. Patients receiving 40 mg of inupadenant plus chemotherapy had an ORR of 53.3%, while patients in the 60-mg cohort had an ORR of 66.7% and those receiving 80 mg had an ORR of 73.3%.
The safety profile for the combo was “manageable and tolerable,” with no dose-dependent toxicity observed, according to the release.
Eight patients remained on the treatment at the data cutoff, according to iTeos.
Detheux said the interim readout was “encouraging” and supports inupadenant’s “differentiated, insurmountable profile” when compared to chemotherapy alone, but that it “does not meet sufficient level of clinical activity to warrant further investment.”
The biotech declined to comment when asked whether it was pursuing an asset sale or licensing. Instead, the company spokesperson said, “iTeos believes inupadenant is a best-in-class A2AR antagonist with a manageable safety profile that could be pursued further in oncology.”
“We remain committed to focusing our resources on developing differentiated, first- or best-in-class therapies and look forward to providing updates on our pipeline in 2025,” Detheux said in the release.
iTeos’ pipeline includes two other clinical-stage programs, one of which is a GSK-partnered TIGIT program.
This September, the pair shared interim phase 2 data for belrestotug, an anti-TIGIT antibody, plus dostarlimab, GSK’s anti-PD-1 treatment sold under the name Jemperli. The combo demonstrated 30% more tumor shrinkage than Jemperli among patients with advanced PD-L1-high NSCLC.
However, patients receiving the combo with belrestotug doses of 100 mg and 400 mg had a 19% rate of discontinuation of both study drugs, which was 13 percentage points higher than in the arm studying dostarlimab by itself, analysts at Leerink Partners said at the time. The rate is also almost double the discontinuation rates reported for Roche's TIGIT/PD-L1 combo of tiragolumab and Tecentriq in the same setting, Leerink Partners said, though Roche reported in November that its phase 3 NSCLC study failed to improve overall survival.
GSK and iTeos are addressing the discontinuations by adjusting the protocol for investigators. The companies have also launched a late-stage study of the investigational TIGIT program.
iTeos’ other clinical asset is a small molecule—dubbed EOS-984—being studied in an early-stage trial as a monotherapy for advanced malignancies.