A combination of ONCOS-102 plus standard chemotherapy continues to extend the time without disease progression and appears to induce immune system activity in people with malignant pleural mesothelioma unable to undergo surgery, updated results from a Phase 2 clinical trial show.
Developed by Targovax, ONCOS-102 is a genetically modified adenovirus designed to infect cancer cells specifically. Once inside these cells, the ONCOS-102 virus produces a protein known as GM-CSF (granulocyte-macrophage-colony-stimulating factor), which stimulates immune system activity against cancer.
The safety and efficacy of ONCOS-102 for adults with malignant pleural mesothelioma is being investigated in an ongoing Phase 1b/2 trial (NCT02879669), sponsored by Targovax
A total of 31 patients were split into two groups, with 20 receiving both ONCOS-102 and the chemotherapy treatments Alimta (pemetrexed) and cisplatin, and 11 patients on chemotherapy only. Injections with ONCOS-102 is given in three cycles at intervals of six weeks, and the chemotherapy in 21-day cycles.
Follow-up exams are being conducted every three months, and data reported here covers nine months of follow-up.
Treatment efficacy is being evaluated using progression free survival (PFS), which is the period on or after a treatment without cancer worsening.
After initial positive results were released in 2018, researchers earlier this year reported that the ONCOS-102 combination led to a significantly greater median PFS compared with chemotherapy only (8.4 months vs. 6.8 months). A slightly higher PFS (8.9 months) was seen in patients given the combination as first-line treatment. According to Targovax, such results compare favorably to data on untreated patients (PFS of 5.7–7.3 months).
Progression free survival benefits at nine months remained consistent with those reported in January.
“We are very pleased to see the encouraging early PFS figures holding up in the 9-month analysis,” Magnus Jäderberg, chief medical officer of Targovax, said in a press release. “The data look particularly promising for first line patients.”
The company intends to prioritize ONCOS-102 as a first-line treatment for mesothelioma, and to release one-year findings in these patients soon.
Researchers have also measured biomarkers of immune system activity as another means of evaluating ONCOS-102’s effectiveness.
They found evidence of greater immune activity, and changes to the area surrounding the tumor in the ONCOS-102-treated group, indicating that the treatment is working as intended.
Targovax, based in Norway, is also planning to investigate ONCOS-102 in combination with an immune checkpoint inhibitor in a future trial with mesothelioma patients.
Like ONCOS-102, checkpoint inhibitors are designed to enhance anti-cancer immune responses, doing so by removing the “brakes” on the immune system used by tumor cells to evade attack.
“The preparations for a subsequent checkpoint inhibitor combination trial in this population with a big pharma collaboration partner are progressing according to plan,” Jäderberg said.