Oncopeptides (ONCO) Study update summary

Initial findings

• Active PDC metabolites were present at pharmacologically relevant concentrations in tumor tissue from the first three surgically evaluated patients, confirming human blood-brain barrier penetration; intratumoral PK aligned with preclinical data and met the primary endpoint for this study part.

• Findings provide clinical proof of concept for delivering a cytotoxic payload into brain tumor cells and support PDC development in solid brain tumors.

Study design and status

• Open-label Window-of-Opportunity study OP-701 (INSULA) evaluates melflufen 30 mg IV on day 1 before surgery in patients with recurrent glioblastoma at Oslo University Hospital.

• Target enrollment is ~10 patients; Cohort I plans five patients to assess blood-brain barrier penetration, while Cohort II explores pharmacodynamics.

• Three Cohort I patients have been surgically evaluated; a fourth is enrolled but has not received study medication. Two patients are in the open-label extension; Patient 1 completed five monthly cycles and Patient 2 completed two.

• Priorities include completing Cohort I and starting Cohort II during 2026; full-study data are expected next year.

• Further PK/PD analyses and recruitment toward the full study population are intended to inform next steps and future PDC development in neuro-oncology.

Safety

• Treatment was well tolerated, with safety consistent with prior clinical experience, no major drug-related toxicity to date, and no unexpected surgical complications.

• Patient 1 had no new tumor-related neurological symptoms; postoperative paresis related to surgery was improving.