TILT Biotherapeutics Reports Promising Phase 1b Results for Ovarian Cancer Treatment

HELSINKI, Finland, Oct. 26, 2026 /CourierPR/ -- TILT Biotherapeutics, a clinical-stage biotechnology company, has announced encouraging results from a Phase 1b portion of its PROTA study, presented at the European Society for Medical Oncology (ESMO) Congress 2026. The study evaluated TILT-123 (igrelimogene litadenorepvec) in combination with MSD's anti-PD-1 therapy KEYTRUDA® (pembrolizumab) and pegylated liposomal doxorubicin (PLD) in patients with platinum-resistant ovarian cancer.

The trial, known as PROTA (NCT05271318), involved 14 patients, with nine being evaluable by Response Evaluation Criteria in Solid Tumours (RECIST) version 1.1 at the time of data cut-off. Four patients achieved confirmed partial responses, corresponding to an overall response rate (ORR) of 44%. Notably, two of these patients subsequently converted to complete responses, while a third continued to demonstrate an ongoing response that had been maintained for 12 months. The fourth responder experienced disease progression 21 months after initiating treatment. Of the remaining five evaluable patients, three achieved stable disease and two had progressive disease, resulting in a disease control rate (DCR) of 78%.

Akseli Hemminki, Founder and CEO of TILT Biotherapeutics, expressed optimism about the findings.

The study builds on results from the Phase 1a portion of PROTA, which reported encouraging safety findings and preliminary evidence of anti-tumour activity with TILT-123 in combination with pembrolizumab. Approximately 100 patients have been treated in five international clinical trials with favourable safety profiles and preliminary evidence of anti-tumour activity.

KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

The Phase 1b study was completed in January 2026, with several patients continuing into an extended treatment period following the initial treatment phase. Some patients are still receiving therapy because of ongoing clinical benefit. The study was designed to evaluate the safety and efficacy of the triplet combination in platinum-resistant ovarian cancer, a significant unmet medical need with limited treatment options once resistance to platinum-based chemotherapy develops.

TILT's approach aims to enhance anti-tumour immune responses through the use of oncolytic immunotherapy in combination with immune checkpoint inhibition and standard therapies. The Company believes these encouraging findings continue to support the development of TILT-123 in solid tumours. The results from the Phase 1b portion of the PROTA study are part of a broader strategy to advance TILT-123 as a potential treatment option for patients with difficult-to-treat cancers.