Who is this for?
This is for men with advanced, castration-resistant prostate cancer (mCRPC) whose cancer has kept growing after the usual treatments — and whose cancer carries the PSMA target on a special scan.
Specifically, the men in this trial had already been treated with:
- Hormone-blocking pills (an ARPI, such as abiraterone or enzalutamide), and
- Chemotherapy — nearly all (97%) had received docetaxel, and about 38% had also had a second chemotherapy, cabazitaxel.
In other words, these were men who had run through the standard options and needed something new. They also had to have a PSMA-positive PET scan — proof that their cancer carried the target this drug seeks out.
What kind of trial is this?
VISION was a large phase III randomized trial — the most rigorous kind — run at 84 hospitals across North America and Europe. It tested whether adding this targeted radiation drug to standard care helped men live longer than standard care alone.
Background: a new way to attack the cancer
When prostate cancer becomes castration-resistant and then keeps growing through chemotherapy, the options narrow and the disease becomes life-threatening. Researchers needed a treatment that worked in a completely different way.
The idea behind this one is elegant. Most prostate cancer cells wear a protein called PSMA on their surface — far more of it than healthy cells carry. If you attach a radioactive atom to a molecule that seeks out PSMA, you can deliver radiation directly to the cancer cells, wherever they are in the body, while largely sparing normal tissue. And because the same PSMA target can be used for imaging, a simple PET scan shows in advance whether a patient’s cancer carries enough of the target to be worth treating. See it, then treat it.
The trial: what was tested and how
VISION enrolled 831 men with PSMA-positive mCRPC who had already had an ARPI and chemotherapy. They were randomly assigned (2 to 1) to one of two groups:
- Lutetium-PSMA + standard care (551 men): an infusion of 177Lu-PSMA-617 every 6 weeks, for 4 cycles — up to 6 if it was helping — on top of the best standard care their doctor chose.
- Standard care alone (280 men): the same standard care, without the radioligand. (Standard care here excluded chemotherapy, other radioactive drugs, and experimental agents, because it wasn’t yet known if those were safe to combine with the new drug.)
The two things the researchers most wanted to measure were how long men lived (overall survival) and how long the cancer was held back on scans (imaging-based progression-free survival).
A note before the results
Harold is a typical 83-year-old patient with prostate cancer. He had his original surgery to remove his prostate 15 years ago, but then his PSA started to climb and he had salvage radiation. A few years later, and again with a rising PSA, he was started on hormone therapy with testosterone suppression (androgen deprivation therapy, or ADT). A bone scan at the time was also positive for metastatic disease, although he felt well.
He started on hormone-blocking pills that worked for a couple of years, but then his PSA started to climb. He tried a few cycles of chemotherapy, but it was tough, and after a few cycles he asked to stop. Now his PSA is rising again and, although he feels well, the only next option is chemotherapy again.
We were able to obtain a PSMA PET, which was positive — opening up another option, with lutetium-PSMA.
Results: what they found
Adding lutetium-PSMA helped on every measure that mattered — men lived longer, the cancer was held back longer, and painful bone complications were delayed.
Lutetium-PSMA + standard care vs standard care alone
Men lived a median of about 4 months longer — a 38% lower risk of death (HR 0.62). Meaningful in a setting where standard options had run out.
The cancer was kept in check more than twice as long — a 60% lower risk of the cancer growing or death (HR 0.40).
Serious bone events (such as a fracture or the need for radiation to bone) were delayed by nearly 5 months (HR 0.50). Importantly, quality of life and pain also worsened later with lutetium-PSMA than without it.
Tumors also shrank far more often: among men with measurable disease, about half (51%) had their tumors shrink, including 9% whose measurable tumors disappeared entirely — compared with 3% on standard care alone.
What are the side effects? (dry mouth, fatigue, low blood counts)
Serious (grade 3 or higher) side effects were more common with lutetium-PSMA than without it (53% vs 38%). The most common problems — mostly mild — were fatigue (43%), dry mouth (39%), and nausea (35%). Dry mouth is characteristic of this drug because the salivary glands also carry a little PSMA, so they pick up some of the radiation; it was almost always mild. The more serious concern is the effect on the bone marrow — lower red cells (anemia), platelets, and white cells — which needs blood-count monitoring. Overall, side effects led to stopping the drug in about 12% of men, and there were a small number (5) of treatment-related deaths, mostly from low blood counts.
How does a doctor know if this treatment will find my cancer?
That’s the elegant part. Before treatment, you have a PSMA PET scan — a special scan that lights up wherever the cancer carries the PSMA flag. If the scan shows the cancer is “PSMA-positive,” the treatment can find those same spots. In VISION, men needed a PSMA-positive scan to take part, so the treatment was matched to the target in advance. Not every man’s cancer expresses enough PSMA, which is why the scan comes first.
Is this the same as external radiation therapy?
No. Ordinary radiation therapy is beamed from a machine outside the body at one area you can point to. Lutetium-PSMA is given as an infusion that travels through the bloodstream and seeks out PSMA-positive cancer anywhere in the body, delivering its radiation from the inside, cell by cell. Because it is radioactive, there are short-term precautions about close contact with others (especially children and pregnant people) for a few days after each dose — your treatment team explains these.
The bottom line
For men with advanced prostate cancer that had stopped responding to hormone therapy and chemotherapy, lutetium-PSMA was the first targeted radiation drug proven to help them live longer. It extended survival (median 15.3 vs 11.3 months), more than doubled the time the cancer was held back on scans, delayed painful bone complications, and shrank tumors in about half of men — all while preserving quality of life. The gains are measured in months rather than a cure, but they came in men who had run out of standard options, and with generally manageable side effects. On the strength of this trial, the drug (marketed as Pluvicto) was approved for this setting, and it is now being studied earlier in the disease.
What this could mean for you
- A new option after hormones and chemo. If prostate cancer has progressed through an ARPI and chemotherapy, lutetium-PSMA may be worth asking about — it works in a completely different way.
- A scan comes first. A PSMA PET scan shows whether your cancer carries the target. If it lights up, the treatment can find it.
- It’s given at specialized centers. Because it is radioactive, it is delivered through nuclear-medicine teams, with simple safety precautions for a few days after each dose.
- Side effects are usually manageable — dry mouth and fatigue are common but mostly mild; blood counts are watched closely.
An oncologist’s perspective
Theranostics is a branch of medicine that many of us do not have much knowledge of, or exposure to. Prior to lutetium-PSMA, we were using a radium compound to help reduce pain in men with metastatic prostate cancer; its survival benefit was modest, and it only reached disease in the bones, not elsewhere in the body. We also use theranostics for rarer neuroendocrine cancers, which express somatostatin receptors.
Now, with the advent of PSMA as a diagnostic and therapeutic tool, we have a whole new treatment modality. If we can find similarly sensitive biomarkers in other cancers, then perhaps theranostics will become more broadly used.
Questions & comments
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