‘Immunotherapy is revolutionizing treatment’
Dr. John Lee, who studies the molecular, cellular and genetic causes of advanced prostate cancer, discussed ongoing efforts to harness the immune system to better recognize and fight cancer. The three immunotherapy approaches that are furthest along in development for prostate cancer patients: an approved T cell-stimulating vaccine, checkpoint inhibitor drugs and cell therapy.
In 2010 the U.S. Food and Drug Administration approved a therapeutic vaccine called Provenge for treating men with advanced prostate cancer. The vaccine turns on T cells to fight cancer cells and has been shown to extend the life of patients. Meanwhile, drugs known as checkpoint inhibitors are helping the immune system defeat cancer in a subset of patients with metastatic prostate cancer.
A bit further from the clinic is adoptive cell therapy, where patients’ immune cells are genetically reprogrammed to attack cancer cells. One version of this tactic is CAR T-cell therapy, where T cells are weaponized with an artificial molecule known as a chimeric antigen receptor, or CAR, that enables immune cells to recognize and kill cancer cells. Some patients with blood cancers have seen astonishing results, but the approach hasn’t had the same success with solid tumors like prostate cancer.
Lee’s research is building CARs that are specific to prostate cancer. It’s early days, he cautioned, “but we’re seeing that with CAR T cells, we can inhibit the growth of prostate cancer in mice. We want to build on these early results and enhance this technology to ultimately bring this to patients and make a huge impact on prostate cancer.”
Imaging advances: Searching and destroying
New technologies for imaging prostate cancer will help doctors detect tumors more effectively and hopefully improve treatment outcomes, said Dr. Evan Yu, a medical oncologist who treats patients with prostate cancer at Seattle Cancer Care Alliance, Fred Hutch’s clinical-care partner.
“Today, the field is moving beyond just finding cancer,” Yu said. “We’re finding new targets for new drugs. We’re imaging with agents and bringing something to the cancer cell that can attack it.”
He highlighted several next-generation uses of PET imaging. PET, or positron emission tomography, uses radioactive dyes that are injected into the patient’s vein and then taken up into certain tissues, like prostate cancer cells, and then revealed on scans.
The FDA has approved the use of novel radiotracers like fluciclovine that can detect prostate cancer at very low levels. That sensitivity can better guide treatment, Yu said.
And these more sensitive PET techniques can power the new field of “theranostics,” which combines imaging and targeted treatment.
“We already have fluciclovine PET imaging, but there are other new imaging and treatment modalities that we will soon bring here to our patients in the Northwest,” Yu said.