The immunotherapy INO-5150 has shown promise as a treatment for prostate cancer that returns after surgery, according to a Phase 1b clinical trial.
Inovio Pharmaceuticals’ cancer vaccine generated immune responses in 60 percent of patients with recurrent prostate cancer and delayed the progression of the disease, researchers said.
The company presented the findings at the European Society for Medical Oncology Congress in Madrid, Sept. 8-12. The poster session was titled “Safety and immunogenicity of a DNA-vaccine immunotherapy in men with biochemically (PSA) relapsed prostate cancer.”
Researchers said INO-5150 triggered immune-system T-cell responses against two proteins associated with prostate cancer in 60 percent of men whose disease had returned. The proteins, PSA and PSMA, are biomarkers of the cancer. The therapy also delayed the progression of the cancer, as assessed through PSA doubling time — the amount of time it takes for PSA levels to double.
“Our study provides encouraging immunologic and clinical data that Inovio’s immunotherapy product can generate antigen-specific CD8+ killer T-cell responses in the blood and link such responses to PSA changes in prostate cancer patients,” Dr. Neil Shore, a prostate cancer specialist at Urologic Associates of North Carolina, said in a press release. “Our results suggest that further evaluation of this product in prostate cancer patients should be explored.”
INO-5150 is a cancer vaccine that encodes the antigens for the PSA and PSMA proteins, which are seen at high levels in prostate cancer. Antigens are parts of a protein that trigger an immune response in the body.
Key objectives of the Phase 1b trial (NCT02514213) were to determine the safety of INO-5150 alone or in combination with INO-9012 and patients’ ability to tolerate it. Researchers also were seeking early signs of the drug’s effectiveness.
INO-9012, Inovio’s other immunotherapy, encodes IL-12 proteins, which trigger the activation and expansion of immune T-cells.
The trial covered 62 patients with recurrent prostate cancer. Researchers wanted to see if INO-5150 was safe and whether it could generate immune responses against PSA and PSMA. They also wanted to know if patients could tolerate the therapy.
To assess safety, researchers recorded the number of adverse events stemming from treatment, injection site reactions, and changes in other parameters.
INO-5150 triggered CD8 T-cell responses against PSA and PSMA in the blood of 60 percent of patients. CD8 T-cells are the killer cells of the immune system.
Researchers also found lower levels of PSA in patients’ blood and a significant increase in PSA doubling time, a surrogate measure of disease progression.
“As a leader in active immunotherapy for cancer with its lead program in Phase 3, Inovio is pleased to report on promising Phase 1b clinical trial data of our prostate cancer therapy INO-5150,” said Dr. J. Joseph Kim, the company’s president and CEO. “The immunotherapy’s ability to generate anti-prostate cancer CD8+ T-cell responses in patients dosed is truly exciting. Perhaps even more importantly, we also observed that the treated patients with better T-cell responses saw a slower rise of PSA levels compared to those without the T cell responses.
“We believe the new clinical data positions INO-5150 as an attractive T-cell-generating immunotherapy component of a potential combination regimen,” he added.