Oncopeptides reports drug uptake in three glioblastoma patients, not proven clinical benefit

Oncopeptides reported on October 9 that its ongoing OP-701, or INSULA, Window-of-Opportunity study had evaluated tumor tissue from three treated patients with recurrent glioblastoma. The open-label study is conducted at Oslo University Hospital in Norway. Its early aim is to assess whether a peptide drug conjugate reaches tumor tissue, not to establish an effective treatment for brain cancer.

The study uses melflufen, also called melphalan flufenamide, as a clinical probe. Patients were scheduled for surgery, allowing researchers to examine resected tumor tissue after administration of the drug. The company reports the presence of active compound in all three evaluated patients and tumor concentrations in line with its preclinical models. These are sponsor-reported findings; the announcement does not provide a completed comparative efficacy trial.

The company says no major drug-related toxicity had been observed in the evaluated patients at the time of its release. It also reports postoperative paresis related to surgery in the first patient, described as improving. A small early cohort and a limited observation period cannot establish safety across patients, exclude uncommon harms or show that a drug improves survival or neurological function.

Recruitment remains ongoing toward approximately 10 patients. The company explains that the study measures drug uptake, tissue distribution and related biological activity rather than long-term endpoints such as progression-free or overall survival. Reaching tumor tissue is a development milestone, not proof that the treatment controls the cancer or benefits patients.

Regulatory status differs by jurisdiction and indication. The European Medicines Agency lists Pepaxti, containing melphalan flufenamide, as authorised for a specific group of adults with refractory multiple myeloma, in combination with dexamethasone. That is not an approval for glioblastoma. In the United States, FDA announced its final decision to withdraw Pepaxto approval on February 23, 2024, because the confirmatory study did not confirm clinical benefit and the available evidence did not show it to be safe or effective under its conditions of use.

The October9 announcement is a company release, not an independently published full clinical study. It should be read as an early tissue-delivery result with unresolved clinical outcomes. It does not establish a new approved brain-cancer treatment, support self-directed use or provide a reason to seek a peptide product outside a regulated clinical setting.