Targovax ASA, a biotechnology company, has recently announced the demonstration of 35% ORR (objective response rate) among anti-PD1 refractory malignant melanoma patients. This significant ORR has been achieved by combining pembrolizumab (Keytruda) and ONCOS-102.

In the 2-part, open-label Phase 1 clinical trial, the combination of anti-PD1 CPI (checkpoint inhibitor) pembrolizumab and ONCOS-102 was tested among patients suffering from advanced, unresectable melanoma. These patients have had disease progression even after receiving the anti-PD1 CPI treatment. Moreover, they are resistant to the approved immunotherapies and other treatment alternatives.

In the trial, there were tumor responses in 7 out of 20 patients treated with this ONCOS-102 & pembrolizumab combination. Additionally, there were several other responses in the non-injected lesions. In 2 patients, a non-injected lesion was disappeared completely, indicating the capability of ONCOS-102 to induce a systemic anti-tumor immunity.

The clinical trial was designed into 2 different parts that assessed various dosing regimens. In the 1st Part, three intra-tumoral injections of ONCOS-102 were given to 9 patients in the 1st week, followed by the systemic treatment using pembrolizumab in every 3rd week for over 24 weeks. Preliminary tumor responses were witnessed among 3 out of the 9 patients, with 1 patient since being considered as non-evaluable.

In Part 2, 12 patients were enrolled to test the extended dosing regimen of twelve intra-tumoral injections of ONCOS-102. In the 1st two weeks, 4 injections were given, followed by the concomitant administration of pembrolizumab and ONCOS-102 from the 3rd week for over 24 weeks. Tumor responses were witnessed in 4 patients in at least 1 CT scan. In addition, patients in Part 2 had more advanced disease, with the majority of them being diagnosed with Stage IV metastatic melanoma.

The response rate in the ONCOS-102 treatment and effect in the non-injected lesions can lead to the significant treatment of patients with anti-PD1 refractory malignant melanoma. The trial was conducted in 3 U.S. sites and one in Norway. Additionally, Memorial Sloan Kettering CC was the coordinating site.

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