Every year, approximately 299,000 American men are diagnosed with prostate cancer, making it the most common cancer in men in the United States. For most, the disease is caught early and treated successfully — surgery, radiation, or active surveillance handle the majority of cases. But for the roughly 10 to 15% of men whose cancer eventually becomes metastatic and resistant to hormone therapy, options have historically been limited and the prognosis poor. A new class of treatment — one that belongs to neither chemotherapy nor immunotherapy, but uses nuclear physics in a way oncology has rarely employed before — has fundamentally changed that outlook. Its approval by the FDA in 2022, backed by a landmark clinical trial published in the New England Journal of Medicine, represents one of the most significant advances in prostate cancer treatment in a decade.
When Prostate Cancer Spreads Beyond the Gland
Prostate cancer is unusual among common cancers in the speed and predictability with which treatment often works — and in the characteristic way it eventually stops working. The overwhelming majority of prostate cancers depend on testosterone and other androgens to grow. Initial treatment typically involves suppressing those hormones through androgen deprivation therapy (ADT), which works well for years. The five-year survival rate for all stages of prostate cancer combined is approximately 97%, one of the highest of any cancer.
But for men whose cancer spreads to lymph nodes, bones, and other organs — metastatic prostate cancer — ADT eventually loses its effect. Tumor cells mutate and find ways to drive their own growth even in a low-testosterone environment. This stage, called metastatic castration-resistant prostate cancer (mCRPC), is where the disease becomes life-threatening. At this point, median survival has historically ranged from about 14 to 18 months, depending on prior treatments and disease burden.
The drugs available for mCRPC before 2022 included next-generation androgen receptor inhibitors (enzalutamide, abiraterone), chemotherapy (docetaxel, cabazitaxel), and PARP inhibitors for patients with specific DNA repair mutations (olaparib, rucaparib). Each has value, but none targets the cancer in a fundamentally new way. The approval of lutetium-177 PSMA-617 changed that — by exploiting a molecular feature that prostate cancer cells display in ways that normal cells do not.
The PSMA Protein: A Target Cancer Reveals Itself
PSMA stands for Prostate-Specific Membrane Antigen, a protein that sits on the surface of prostate cells. In normal prostate tissue, PSMA is present at low levels. In prostate cancer cells, PSMA is expressed at dramatically elevated levels — typically 100 to 1,000 times higher than in normal tissue. Critically, as prostate cancer progresses and becomes more aggressive and treatment-resistant, PSMA expression tends to increase further. The more dangerous the cancer, the more it advertises itself through PSMA.
This creates a therapeutic opportunity. If you can build a molecule that seeks out and binds to PSMA, you have a targeting system that will find prostate cancer cells throughout the body — in bone metastases, lymph nodes, liver, or anywhere else the cancer has traveled — while largely sparing the surrounding tissue. PSMA expression is low in most normal organs, with the exception of the kidneys, salivary glands, and small intestine, which have some physiological PSMA activity. This limits side effects substantially compared to drugs that hit all rapidly dividing cells indiscriminately.
The concept of using PSMA as a cancer-targeting GPS has driven two parallel innovations: a new imaging technique (PSMA PET scanning) that can detect tiny metastatic deposits that MRI and conventional CT miss, and a new treatment (radioligand therapy) that exploits the same GPS to deliver a lethal payload directly to those deposits.
How Radioligand Therapy Works
Lutetium-177 PSMA-617 (brand name Pluvicto, manufactured by Novartis) belongs to a class of drugs called radioligand therapies (RLTs) — sometimes also called theranostics, because the same targeting molecule can be used for both diagnosis (with an imaging isotope attached) and therapy (with a therapeutic isotope attached).
The drug has two components bound together. The first is a small molecule called PSMA-617, which has a high affinity for the PSMA protein — it binds to PSMA the way a key fits a specific lock. The second is lutetium-177, a radioactive isotope that emits a form of radiation called beta particles when it decays.
When Pluvicto is injected into the bloodstream, the PSMA-617 component circulates throughout the body seeking cells that display PSMA on their surface. When it finds a PSMA-expressing prostate cancer cell — whether in a bone metastasis, a lymph node, or anywhere else — it binds tightly to it. Once bound, the lutetium-177 delivers its radiation payload directly into the cancer cell from the inside. The beta particles emitted by lutetium-177 have a short tissue penetration range of about 1 to 2 millimeters, meaning the radiation kills the cancer cell and its immediate neighbors but does not travel far enough to damage tissue at a distance.
The result is something that was impossible with earlier cancer treatments: systemic, whole-body targeted radiotherapy. Instead of delivering radiation to a defined external beam target (which requires knowing exactly where every tumor is), radioligand therapy sends the radiation to every PSMA-expressing cancer cell throughout the body simultaneously, guided by the cancer’s own molecular marker. One injection becomes, in effect, an internal radiation treatment for every metastatic deposit at once.
The VISION Trial: What the Evidence Shows
The definitive evidence for lutetium-177 PSMA-617 came from the VISION trial (NCT03511664), a global Phase 3 randomized controlled study published in the New England Journal of Medicine in June 2021. The trial, led by Oliver Sartor at Tulane Cancer Center and Johann de Bono at the Institute of Cancer Research London, enrolled 831 men with PSMA-positive metastatic castration-resistant prostate cancer who had previously received both a next-generation androgen receptor pathway inhibitor (abiraterone or enzalutamide) and at least one taxane-based chemotherapy regimen.
These were heavily pretreated patients who had already exhausted the most commonly used treatment options for their disease. Eligibility required that their tumors express PSMA on PSMA PET-CT imaging — a step that both selected the patients most likely to respond and validated PSMA imaging as a companion diagnostic tool.
Patients were randomized in a 2:1 ratio: two-thirds received lutetium-177 PSMA-617 (administered as six intravenous infusions every six weeks) plus standard of care; one-third received best standard of care alone. The two co-primary endpoints were radiographic progression-free survival (rPFS: time until the cancer visibly progressed on imaging) and overall survival.
The Numbers in Plain Language
The results were decisive across both primary endpoints. Patients receiving lutetium-177 PSMA-617 had a median rPFS of 8.7 months versus 3.4 months in the control arm — a hazard ratio of 0.40, meaning a 60% lower risk of radiographic progression or death at any given point during the trial.
Overall survival improved from 11.3 months in the control arm to 15.3 months with lutetium-177 PSMA-617 — a hazard ratio of 0.62, representing a 38% reduction in the risk of death. In a disease context where gaining additional months of survival is a meaningful clinical achievement, nearly four additional months of median overall survival in a previously treated population is a substantial result.
Response rates reinforced the picture. Among patients with measurable soft-tissue disease, the objective response rate was 29.8% with lutetium-177 PSMA-617 versus 3.4% in the control group. PSA response (a decline of ≥50%) was observed in 46% of lutetium-treated patients versus 7.1% of controls.
The safety profile was considerably more favorable than chemotherapy. The most common side effects were fatigue (43%), dry mouth due to salivary gland uptake (39%), nausea (35%), and anemia (32%). Grade 3 or 4 adverse events occurred in 52.7% of patients, compared to 38.0% in the control group — a meaningful but not prohibitive increase, particularly given the severity of the disease being treated. Serious bone marrow suppression was manageable. No unexpected safety signals emerged.
Based on these results, the FDA granted full approval to Pluvicto (lutetium vipivotide tetraxetan) on March 23, 2022 — the first radioligand therapy ever approved for prostate cancer, and only the second radioligand therapy approved for any cancer by the FDA. The speed of the approval, and the breadth of its coverage in scientific and mainstream media, reflected the oncology community’s recognition that a genuinely new therapeutic modality had arrived.
PSMA PET Scanning: Seeing What MRI Misses
Radioligand therapy is only half of the PSMA-based revolution in prostate cancer. The same molecular targeting that makes lutetium-177 effective also powers a new generation of imaging that has substantially improved how prostate cancer is staged and monitored.
PSMA PET-CT scanning uses a PSMA-binding molecule tagged with a positron-emitting isotope (commonly gallium-68 or fluorine-18) instead of a therapeutic one. The result is a whole-body scan that lights up wherever PSMA-expressing prostate cancer cells are present — including tiny lymph node deposits and early bone metastases that are invisible on conventional CT and bone scans.
The proPSMA trial, published in The Lancet in 2020, compared PSMA PET-CT to the previous standard imaging combination (CT plus bone scan) in high-risk prostate cancer patients before surgery or radiotherapy. PSMA PET-CT achieved an accuracy of 92% versus 65% for conventional imaging — identifying spread that conventional imaging missed in 27% of cases, and avoiding false-positive findings that would have led to unnecessary treatment modifications. In a disease where staging accuracy determines whether a patient receives curative-intent local treatment or systemic therapy, this is a clinically profound difference.
The FDA approved two PSMA PET imaging agents for prostate cancer: Gallium-68 PSMA-11 (in 2020, for University of California sites, then more broadly) and piflufolastat F-18 (Pylarify) in 2021, with subsequent approvals for other agents following. PSMA PET is now a standard staging tool at major prostate cancer centers and is increasingly available nationally.
The connection between imaging and treatment is direct: PSMA PET-CT is also used to confirm PSMA expression before prescribing Pluvicto — a patient whose tumors do not express PSMA adequately on imaging would not be expected to benefit from PSMA-targeted therapy, and the FDA label requires PSMA-positive imaging as a prerequisite for treatment.
PSMAfore: Moving the Treatment Earlier
The VISION trial established lutetium-177 PSMA-617 as an effective treatment after prior chemotherapy. A natural follow-up question was whether the drug could work even earlier in the treatment sequence — before chemotherapy, in patients whose cancer has become castration-resistant but who have not yet required taxanes.
The PSMAfore trial (NCT04689828), published in The Lancet in 2024, enrolled patients with taxane-naive mCRPC who had progressed on one prior androgen receptor pathway inhibitor (such as enzalutamide or abiraterone). Patients were randomized to receive lutetium-177 PSMA-617 or a switch to a different ARPI — the approach most physicians would use at this point in the standard treatment algorithm.
Lutetium-177 PSMA-617 outperformed the ARPI switch decisively: median radiographic progression-free survival was 11.6 months versus 5.7 months (hazard ratio 0.41, p<0.0001). This moved the potential window for radioligand therapy substantially earlier in the disease course, before patients had been exposed to taxane-based chemotherapy and at a point when their performance status and organ function are typically better.
Regulatory applications based on PSMAfore data have been filed in multiple markets. The trajectory points toward lutetium-177 PSMA-617 eventually becoming a standard second-line option after first ARPI failure, considerably expanding the number of eligible patients.
What This Means for Patients Today
For men with prostate cancer and their families navigating the current treatment landscape, several practical points deserve attention:
- Ask for PSMA PET-CT imaging at staging and at progression. If you have high-risk prostate cancer being evaluated before surgery or radiation, or if your PSA is rising after local therapy, PSMA PET-CT provides significantly more accurate staging information than conventional CT and bone scan. At major cancer centers, it is already the standard of care for high-risk and biochemically recurrent disease. If you are being managed at a community practice, ask whether PSMA PET imaging is available or whether a referral to a center that offers it is appropriate.
- Ask about PSMA expression testing. Pluvicto (lutetium-177 PSMA-617) requires confirmation of adequate PSMA expression on PET imaging before treatment. The imaging and the therapy go together: the scan that stages your disease is also the test that determines whether you are eligible for the treatment.
- Understand the current approved indication. As of the FDA’s March 2022 approval, Pluvicto is indicated for PSMA-positive mCRPC in adults who have received at least one androgen receptor pathway inhibitor and at least one prior taxane-based chemotherapy. If you are in earlier stages of disease, this treatment is not yet approved for your situation — but the PSMAfore data and ongoing trials may change that in the near future.
- Seek treatment at a center experienced with radioligand therapy. Pluvicto requires specific nuclear medicine infrastructure for safe preparation and administration: the drug is radioactive and must be handled under radiation safety protocols. Not all oncology practices can offer it. Academic medical centers and comprehensive cancer centers with nuclear medicine departments are the appropriate setting. Referral from your primary oncologist is the typical pathway.
- Ask about clinical trials. Multiple trials are actively investigating lutetium-177 PSMA-617 in earlier disease settings (PSMA-ATLAS in biochemically recurrent disease, PSMAddition in metastatic hormone-sensitive disease) and in combination with other agents. These trials may offer access to treatment not yet available outside the study setting. CancerInsight’s clinical trial search tool and ClinicalTrials.gov can help you identify recruiting studies near you.
- Keep track of BRCA and DNA repair mutation status. Men with mCRPC who have mutations in BRCA1, BRCA2, or other homologous recombination repair genes are also eligible for PARP inhibitor therapy (olaparib, rucaparib). Testing for these mutations should be done at the time of metastatic diagnosis if not already performed. Multiple treatment options — including radioligand therapy and PARP inhibitors — may be sequenced for maximum benefit.
What Comes Next
The VISION approval opened a door that the prostate cancer research community is now moving through rapidly. Several major trials are defining the next phase of radioligand therapy’s role in prostate cancer treatment:
Earlier-stage applications. The PSMAddition trial is comparing lutetium-177 PSMA-617 plus standard of care versus standard of care alone in metastatic castration-sensitive prostate cancer — the stage before castration resistance develops. If positive, it would move radioligand therapy to the very beginning of the metastatic treatment sequence. The PSMA-ATLAS trial is investigating Pluvicto in biochemically recurrent prostate cancer after local therapy, in patients with rising PSA but no detectable metastases — a much earlier disease state than any currently approved indication. Results are anticipated in coming years.
Combination approaches. Researchers are exploring lutetium-177 PSMA-617 combined with PARP inhibitors (which may enhance radiation-induced DNA damage in tumors), androgen receptor inhibitors, and immunotherapy agents. Early-phase data are generating hypotheses about which combinations produce synergistic effects, though no combination has yet produced Phase 3 evidence.
The theranostics paradigm extends beyond prostate cancer. The success of PSMA-targeted radioligand therapy has accelerated interest in applying the same theranostic approach to other cancers. Fibroblast activation protein (FAP), which is expressed in the tumor microenvironment of many cancer types, and other tumor-specific antigens are being explored as radioligand targets. The intellectual framework — find a target the cancer overexpresses, build a molecule that binds it, attach a therapeutic isotope — is cancer-agnostic, and prostate cancer is providing the clinical proof of concept the field needed.
For men living with advanced prostate cancer, the message from the VISION trial and its successors is clear: the treatment options available today are meaningfully better than those available five years ago, and the pipeline of options in development is deeper than it has ever been. Radioligand therapy is not a cure — the cancer continues to evolve, and resistance to PSMA-targeted therapy is being actively studied. But for a disease that was once described as approaching a therapeutic ceiling, the ceiling has moved substantially higher.