Radiopharmaceutical therapy (RPT) is a revolutionary treatment that targets metastasized tumors at the cellular level, reducing radiation exposure to normal, healthy tissue and reducing significant side effects – a possibility that occurs with conventional external radiation therapies.
“RPT uses radioisotope therapy in the process of delivering the radiation intravenously to cancer cells by adding radioactive material, or radionuclides, to proteins that bind with the receptors on the cancer cells, destroying those cells,” explained Nitin Vaishampayan, M.D., radiation oncologist, physician lead for radiopharmaceuticals at the Barbara Ann Karmanos Cancer Institute, and member of the Gastrointestinal and Neuroendocrine Oncology and Genitourinary Oncology Multidisciplinary Teams, among others.
Medical and radiation oncologists often see RPT as an option for patients who have failed previous lines of treatment, such as androgen deprivation therapy for prostate cancer, and lanereotide and octreotide used to treat neuroendocrine cancer. RPT is non-invasive and does not require daily visits; patients receive infusions at a small number of appointments spread out over months. RPT is also painless, and most patients tolerate the treatment well. However, before this therapy is suggested, clinicians must investigate whether the compound can find the patient’s tumor cells.
“Each patient recommended for this treatment must undergo pre-imaging with a PET scan,” said Dr. Vaishampayan. “During this initial part of the process, we use an imaging version of the compound. We must see on the PET scan that the imaging compound is expressed on the surface of the cancer cells to move forward with radiopharmaceutical therapy. This ensures that the radioisotope is delivered accurately to the target cells with less uptake by normal tissues. If the PET scan does not show avidity for the target molecules, then we have other treatment options that we can recommend.”
Karmanos has been a pioneer in Michigan, using radiopharmaceuticals since 2017, with over 650 infusions completed to date. The latest FDA-approved radiopharmaceuticals are available to Karmanos patients, including Lutathera™ (177Lu-DOTA0-Tyr3-octreotate), used to treat neuroendocrine tumors that have spread throughout the body. The targeted agent is given to patients as an intravenous line (IV) treatment. Lutathera™ targets the somatostatin receptors found within neuroendocrine cancers.
“Patients who are getting Lutathera™ receive four- or five-hour treatments every two months – a total of four infusions,” said Dr. Vaishampayan.
FDA-approved metastatic prostate cancer treatments, Pluvicto™ (177Lu vipivotide tetraxetan) and Xofigo® (radium Ra 223 dichloride), are also available at Karmanos. Dr. Vaishampayan was a co-investigator in the nationwide VISION phase 3 clinical trials that used the PSMA-targeted radioligand 177Lu-PSMA-617 for patients with prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer (mCRPC). The study was published in The New England Journal of Medicine in 2021 and led to the FDA approval of Pluvicto™.
“When treating with Pluvicto™, patients receive outpatient treatment every six weeks for a maximum of six infusions. Appointment times are usually less than one hour,” Dr. Vaishampayan explained.
Xofigo® is FDA-approved treatment for bone metastatic prostate cancer that is no longer responding to androgen deprivation therapy. This treatment is given with an intravenous injection once every four weeks for a total of six injections. Xofigo® is also being investigated at Karmanos in a current clinical phase II trial of radium-223 dichloride in combination with paclitaxel in patients with bone metastatic breast cancer.
“Randomized studies have shown a modest survival advantage for the use of Xofigo®, Pluvicto™, and Lutathera™ for patients who meet the treatment criteria,” added Dr. Vaishampayan. “We’re excited that these new lines of treatment at Karmanos have been well tolerated, and we look forward to the additional tumor sites we are investigating to expand this treatment to more patients.”
Along with Dr. Vaishampayan, radiation oncologists Steven Miller, M.D., and Michael Dominello, D.O., also treat patients with radiopharmaceuticals. To learn more about the radiation therapy treatments available at Karmanos, click here. To begin the referral process for a patient you know could benefit from radiopharmaceutical treatment, visit karmanos.org/refer or call 1-877-KARMANOS.