A decade ago, only a few radiopharmaceutical agents were used to help treat cancer patients. That has changed and the field of theranostics is expanding rapidly in various ways, as described in part 1 of AuntMinnie.com's series on the rise of theranostics.
However, few freestanding theranostics centers exist today. Even if some private urology, radiation oncology practices, or radiologist groups are building the ability to perform theranostics, experts are cautious about patient management, radiation safety, and the risk of unnecessary imaging. They're also mindful of the multiple dedicated teams required to build a theranostics clinic properly.
AuntMinnie.com asked leaders in the field to discuss what to know before branching into prostate cancer theranostics.
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A decade ago, only a few radiopharmaceutical agents were used to help treat cancer patients. That has changed and the field of theranostics is expanding rapidly in various ways, as described in part 1 of AuntMinnie.com's series on the rise of theranostics.
However, few freestanding theranostics centers exist today. Even if some private urology, radiation oncology practices, or radiologist groups are building the ability to perform theranostics, experts are cautious about patient management, radiation safety, and the risk of unnecessary imaging. They're also mindful of the multiple dedicated teams required to build a theranostics clinic properly.
AuntMinnie.com asked leaders in the field to discuss what to know before branching into prostate cancer theranostics.
Thomas Hope, MD, a radiologist and nuclear medicine physician at the University of California, San Francisco (UCSF), said that approval of lutetium-177 (Lu-177) prostate-specific membrane antigen (PSMA) radioligand has driven a marked interest and excitement about theranostics and radioligand therapies (RLT). Hope, vice chair of clinical operations and strategy in the UCSF department of radiology, established the radioligand therapy group at the university. He also helped lead the theranostics conference at the Society of Nuclear Medicine and Molecular Imaging (SNMMI) 2024 midwinter meeting.
Not your thyroid theranostics
For nuclear medicine physicians who haven't really managed patients with prostate cancer, Hope said, they will want to understand the theranostics business model, therapy center workflow, and best way to staff the nurse team, in addition to the role of the nuclear medicine physician relative to the medical oncologist.Â
North of 600 theranostics treatments are administered at UCSF each year, with a team of five people. Up to now, most Lu-177 DOTATATE therapies for the treatment of somatostatin receptor-positive neuroendocrine tumors (NETs) have, for example, been administered only within the top 20-40 of between 300 and 400 sites -- larger academic centers like UCSF or private practice hospitals -- in the U.S., Hope added.
"But prostate cancer will be different," Hope continued. "A lot of care will be provided in the community, so this will be a very different setting than we've seen historically with radioligand therapies."
Hope explained that a key problem with setting up a theranostic practice for prostate cancer is understanding patient management. The key is multidisciplinary care and creating a nursing team to manage the workflow of patients undergoing treatment.
Expect growing pains
"How many centers have true multidisciplinary teams in which nuclear medicine, medical oncology, and radiation oncology are working hand-in-hand in clinics to best treat these patients?" asked Michael Morris, MD, of Memorial Sloan Kettering Cancer Center in New York for an article in the Journal of Nuclear Medicine (JNM) last year. Morris specializes in prostate cancer and new investigational agents.
"How many centers have the physical space in their nuclear medicine departments to treat a disease as common as prostate cancer?" Morris continued in the JNM. "It’s really a need to organize joint care for patients, upskilling the medical oncologists to understand nuclear medicine issues and nuclear medicine physicians to understand general medical oncology issues. This process will go through growing pains."
Who should champion theranostics?
"It's really critical that someone -- typically the nuclear radiologist -- champions this process and leads this cohesive, multidisciplinary team approach," Penny Vroman, MD, told AuntMinnie.com. Vroman is a dual board-certified nuclear radiologist and associate professor at the University of Texas (UT) Health Science Center in San Antonio.
Having practiced theranostics for over a decade, Vroman is among those watching the outcomes of potentially practice-changing clinical trials that could open doors for theranostics agents as first-line therapies in 2024 and as a replacement for chemotherapy within the next five to 10 years.
"These targeted molecular therapies really do bind to the cancer cells and primarily kill the cancer cells," Vroman said. She shared her experience and perspectives on standing up a theranostics practice in an interview recently with AuntMinnie.com.
"I would recommend starting with a pilot program of five to 10 patients to help test the program's processes," Vroman explained. "And then once these processes have been optimized, then opening up the therapy to the community.
"The issue is you really do need an experienced, authorized user (AU) to administer these therapies," Vroman continued, "who knows all the rules, regulations, requirements for dealing with radioactive material and treatment."
Building theranostics takes time
For the well-established theranostic practice at UT Health, it took about one year to add one new treatment, Pluvicto, into the practice as a new targeted molecular therapy for prostate cancer.
"It's a very complex process to stand up such a program or add a new therapeutic theranostic agent," Vroman explained. "It requires a dedicated multidisciplinary team to include our nuclear radiologists, our nuclear medicine technologists, radiation safety team, our oncologists; the radiopharmaceutical manufacturer; our administrative team to include financial analysts, coders; public affairs; leadership team, to include radiology department, UT health leaders. And we would all meet on a nearly monthly basis to discuss our process, our workflows, logistics."
Even after all of the teams and processes were in place and treatments had begun, the group reviewed all of the processes on a regular basis and discussed areas for possible improvement, she said.
"Now that we've successfully started this therapy program for prostate cancer patients, we're actively working on introducing theranostic therapy for neuroendocrine cancer patients too," she added.
PSMA imaging agents
Experience of the treating and interpreting providers plays a critical role in the PSMA imaging agent decision-making process, in particular given the types of cancers patients may have already been treated for, David Albala, MD, chief of urology at Crouse Hospital and medical director of Associated Medical Professionals in Syracuse, NY, told Urology Times in December 2023.
"Our choice aligns with the expertise of our radiologists, who become highly skilled in reading scans with the same agent repeatedly," Albala said in the article.
Providing guidance to physicians treating prostate cancer, the American Society for Clinical Oncology (ASCO) in September 2023 issued a rapid recommendation systemic therapy update to its prostate cancer guidelines.Â
When, in 2022, the U.S. Food and Drug Administration (FDA) first approved Pluvicto for the treatment of adult patients with prostate-specific membrane antigen-positive metastatic castration-resistant prostate cancer (mCRPC), the FDA also approved Locametz (Ga-68 gozetotide) as the radioactive diagnostic agent to use in PSMA-PET for patient selection, according to the FDA.
Nuances, availability prompt new guidelines
"After that approval, the primary imaging modality at the time of this initial drug [Pluvicto] approval was based on gallium-68, which was used in that clinical trial, which was VISION," stated lead author of the ASCO update Rohan Garje, MD. Garje is chief of genitourinary medical oncology at the Miami Cancer Institute at Baptist Health South Florida.
"Since then, we have access to a couple of new radiotracers, one of them being piflufolastat, also called Pylarify, and the newer one called flotuflastat F-18, which is also called Posluma, as additional imaging agents to detect PSMA-positive lesions [on a PSMA scan]," Garje continued, "... we thought to add these additional choices for patient selection because this provides the treating physicians additional options because there really are nuances involved in these imaging agents."Â
For ASCO, Garje explained that one of the reasons behind these additional agents is that each institution may have limited access to certain imaging agents, and other agents may be equally good in their detection of PSMA.
"For example, if a patient had a testing done by piflofolastat or flotufolastat, if they are PSMA-positive, it has shown PSMA-positive lesions as per VISION criteria, we do not suggest the patients to undergo gallium-68 assisted imaging again to have selection for PSMA lutetium therapy. This is unnecessary imaging," Garje said. "We have evidence now, based on the studies which were done with Pylarify, which is the piflofolastat, or the flotufolastat, which is Posluma, that they are equally good in detecting PSMA-positive lesions. This way we can avoid additional imagings for patients who are being screened for lutetium therapy."
Key to a good theranostics center
Stay tuned for the next article in this series.
