We have an open clinical trial using radioimmunotherapy for men who have been diagnosed with prostate cancer, and whose PSAs are rising despite initial hormonal therapy but have no evidence of metastatic disease on scans (no tumors seen on CT/MRI and bone scan). This clinical trial is investigating whether attaching Lutetium 177 with the monoclonal antibody J591 (177Lu-J591) can delay or prevent the disease progression to overt metastatic disease in men with “biochemical progression”.
J591 can recognize a protein antigen known as PSMA (also known as anti-prostate-specific membrane antigen) that is present on the surface of nearly all prostate cancer tumors and circulating tumor cells.
The targeted treatment in this trial uses J591 as a delivery vehicle for the radioactive treatment (Lutetium 177) to be delivered directly to the prostate cancer cells that may be hiding or circulating in the body (for example in lymph nodes, the blood stream or the bones).
The Lutetium 177-J591 treatment approach may be ideal for men who are experiencing rising PSA levels after primary prostate cancer treatment and early hormonal therapy, but whose bone and CT scans remain negative. Even though we can’t detect the presence of cancer on these traditional imaging scans, we know from prior research that these men have what we call “micro-metastatic” disease, meaning that the prostate cancer cells are increasing throughout the body because otherwise PSA levels would not be so high or increasing at such a rapid rate. Unfortunately, even with traditional hormonal manipulation, metastases become evident in these men after months. Although we have treated many men with overt metastatic prostate cancer and demonstrated anti-tumor responses, we have also shown that we are able to target these micro-metastatic sites (tumors that are too small to be seen on CT or bone scan), and the properties of 177-Lu make it more optimal for tumors that are too small to be seen on conventional imaging.
Many patients fall in this category in a broad sense and usually these men feel completely fine. Approximately 50,000 new men per year in the U.S. suffer a biochemical relapse (rising PSA after surgery or radiation) and some of these men will have further PSA rises despite the most common type or hormonal therapy, which are injections to bring down testosterone levels. The goal is to intervene earlier on in order to bring more men to cure and suppress the disease from further progression and metastases.
Men in this phase II study will be randomized and all patients will receive oral hormonal therapy as part of treatment which also serves to boost their PSMA level (i.e. increase the number of “locks” per tumor cell). Since PSMA is the target for 177Lu-J591, radioimmunotherapy increased expression of PSMA can lead to more targeting of the otherwise invisible tumor cells. Two-thirds of patients will receive 177Lu-J591 at the highest tolerated dose that improved outcomes based on our prior study and the remaining one-third will get J591 with a diagnostic isotope (111Indium). The isotope 111-Indium (abbreviated 111In) is also an energetic radioactive particle, but it does not generally give off enough energy to kill cancer cells while still allowing researchers to take more detailed pictures of where the prostate cancer is located in the body.
Our goal is to ultimately cure the men who fall in this category by eradicating microscopic deposits of cancer, and the Weill Cornell Genitourinary Oncology team is available for patient consultations and to speak with physicians who are interested in referring patients to this trial, which is available at a number of sites across the country.
Learn more about how this treatment works in this article and video:
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