SillaJen said a combination of its oncolytic viral therapy Pexa-Vec (JX-594) with immune check inhibitor Libtayo (ingredient: cemiplimab) has reduced tumor in 12 out of 16 kidney cancer patients. It also shrank the size of the tumor more than 30 percent in nine out of the 12 patients, the company added.
The company released the interim results of the Phase-1b trial at the meeting of the American Association for Cancer Research (AACR) on Monday.
Twelve out of the 16 patients available for analysis had a 75 percent disease control rate (DCR), which combined complete response (CR), partial response (PR), and stable disease (SD). More specifically, one showed CR, and five, PR. Six had SD without cancer progression, and four, progressive disease (PD) with cancer progression.
In total, 12 out of 16 patients had tumor size reduction, and nine among them had more than 30 percent tumor burden reduction. However, three patients had either progressive or stable disease because new lesions appeared.
In terms of safety, 5.7 percent of patients showed severe adverse reactions of Grade 3 or higher. Most of the other adverse reactions were mild side effects such as fever immediately after a drug administration and a temporary increase in blood pressure.
Even though the study did not directly compare the combined therapy with Libtayo alone, the combo could be effective given the immunotherapy’s low response rate at around 20 percent, the company said.
“The latest findings partially demonstrated that Pexa-Vec plus immunotherapy might be more effective than immunotherapy alone,” SillaJen said. “It is particularly encouraging that the mechanism of Pexa-Vec, which had been proved in an animal test last year, was proven to have the same effect in humans.”
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