Two Agents Approved For Psma
On May 26, FDA approved piflufolastat F 18 for use in a type of imaging procedure called PSMA PET in people with prostate cancer. The approval covers the use of piflufolastat F 18 in patients suspected of having metastatic prostate cancer or recurrent prostate cancer . Last year, the agency approved another imaging agent for PSMA PET, Ga 68 PSMA-11, for the same uses, but its use is largely limited to the two institutions where it is made.
In a statement, Lantheus, which manufactures piflufolastat F 18, said the imaging agent will be immediately available in parts of the mid-Atlantic and southern regions with broad availability across the U.S. anticipated by year end.
PSMA is often overproduced by prostate cancer cells but is generally not produced by most normal cells, making it an excellent target for both PET imaging and targeted systemic radiation therapy like 177Lu-PSMA-617, Dr. Morris said.
What Are The Benefits Of Psma Pet Treatment At Ucsf
- FDA approved imaging technique for prostate cancer.
- The PSMA PET scan can identifiy cancer that is often missed by current standard-of-care imaging techniques.
- The PSMA tracer can also be used in conjunction with CT or MRI scans.
- UCSF is only one of two medical centers in the U.S. that offers the FDA approved PSMA PET.
- PSMA PET is more effective and precise for localizing mestatic prostate cancer.
- UCSF researchers, along with colleagues at UCLA, studied PSMA PET for several years to better precisely locate prostate cancer.
- PSMA PET works using a radioactive tracer, called 68Ga-PSMA-11, which is manufactured on site at UCSF.
How Do Psma Pet Scans Work And What Are Their Benefits
Weve been using PET imaging to detect cancers for decades. Until recently, however, we havent been able to image prostate cancer well because older PET radiotracers these are radioactive molecules that stick to cancer cells and can be seen on PET scans do not routinely bind to prostate cancer. However, a new radiotracer, piflufolastat F-18 , does bind to the PSMA on prostate cancer cells. Doctors can look at a PET scan and see if piflufolastat lights up prostate cancer cells anywhere in the body. Today, PSMA PET is the single best method we have to precisely visualize prostate cancer in the body. Knowing the anatomic location of prostate cancer helps us make better treatment decisions and monitor a patients response to therapy.
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Treating Pca With A Psma
Targeted antibodies are a class of cancer immunotherapy treatment that send signals to the immune system to kill cancer cells. Antibodies are naturally produced proteins that target and bind to antigens on the cell surface.
There are now several types of targeted antibodies being researched for cancer treatment, including
- Monocolonal antibodies , which target tumor cells rather than immune cells
- Antibody-drug conjugates , which combines targeted antibodies with anti-cancer drugs
- Bispecific antibodies, which can bind to two different targets
Researchers have developed several antibodies that are targeted at PSMA to eliminate prostate cancer cells. The first anti-PSMA antibody was the mAb 7E11, which recognized and bound a PSMA intracellular or cytoplasmic epitope. Newer antibodies have been developed to bind at different locations, such as the extracellular portion of PSMA. Additionally, recent PSMA antibodies are either fully immune or humanized, as opposed to murine antibodies.
Axumin Pet Scanning For Prostate Cancer Care
Axumin is an FDA-approved agent used for Axumin PET scans for prostate cancer. Axumin is often able to image and restage recurrent prostate cancer better than any other conventional imaging techniques. Biochemical recurrence, typically suspected with rising PSA levels, is the standard in monitoring patients for suspected recurrent prostate cancer. Traditional imaging techniques are often limited in that they may detect a small lymph node or suspicious finding, but cannot further functionally characterize the molecular activity to determine the level of suspicion. The introduction of Axumin PET scanning has been a breakthrough, allowing physicians the ability to accurately locate and restage prostate cancer with precision, especially in the setting of suspiciously rising PSA levels.
How Do Axumin PET Scans Work?
An Axumin PET uses a radioactive tracer, given as an injection, that is linked to an amino acid which is absorbed by prostate cancer at a much more rapid rate than normal cells. The rapid uptake of Axumin by prostate cancer cells is then imaged by the advanced technology within the PET scan equipment. The PET scan images are then reviewed in order to determine if there has been any spread to other areas in the body.
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How Long Does A Psma Scan Take
The PSMA PET scan usually takes about 2 hours, although timing may vary.
To conduct a PSMA PET scan, a nurse or technician will inject a special dye with a radioactive tracer into one of your veins. They will ask you to wait approximately 30 to 60 minutes to allow the dye to travel throughout your body.
Next, they will ask you to lie down on a padded exam table. They will slide the table through a PET-CT or PET-MRI scanner to create images of your body. This scan may take 30 minutes or longer to complete.
After the scan is finished, a specialist will review the images and report the results to your doctor. Your doctor will share the results with you.
Ask your doctor how long it will take to receive the results of the scan.
Improved Survival Largely Safe For Patients
The VISION trial enrolled 831 people with metastatic castration-resistant prostate cancer. All of them had previously been treated with chemotherapy and other standard treatments, such as enzalutamide and abiraterone . In addition, all participants had PSMA-positive tumorsthat is, their tumors overproduced PSMAas determined by PSMA PET imaging.
Trial participants were randomly assigned to receive treatment with 177Lu-PSMA-617 along with their physicians choice of treatment, which had to be among several commonly used options for cancers no longer responding to other established treatments, or their physicians treatment choice alone.
Physicians’ choices of treatment could not include chemotherapy or radium-223 , a radiopharmaceutical specifically used to treat bone metastases in patients with prostate cancer. The typical options included enzalutamide or abiraterone as well as palliative treatments, like radiation and steroids, Dr. Morris explained in an interview. Under the trials design, doctors could adapt treatment as they felt necessary.
We were trying to mirror practices in this particular context, he said. If the patient needed a change, they could go from one treatment to another.
In addition to improving how long patients lived overall, participants treated with 177Lu-PSMA-617 also had improved progression-free survival, which is how long somebody lives without their cancer getting worse: 8.7 months versus 3.4 months.
| Treatment group | |
| 11.3 months | 3.4 months |
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Is Psa The Same As Psma
The PSA test is different from the PSMA PET scan.
The PSA test is a blood test that measures the level of PSA in your blood. PSA is a protein produced by cells in your prostate gland. High levels of PSA are often a sign of prostate cancer.
The PSMA PET scan is used after PSA testing if your doctor isnt sure if or where prostate cancer has spread. It can more accurately pinpoint where prostate cancer cells are located throughout the body.
Your doctor may order a PSA blood test to:
- screen for prostate cancer if you dont have symptoms of the disease
- determine whether further tests are necessary to diagnose prostate cancer if you do have symptoms of the disease
- check for signs that prostate cancer has come back if youve received successful treatment for the disease
PSA blood test results are not enough to diagnose prostate cancer or learn whether it has spread or returned. If you have high levels of PSA, your doctor will order other follow-up tests to develop an accurate diagnosis.
Your doctor will only order a PSMA PET scan if they think you may have prostate cancer that has spread beyond the prostate gland.
Greater Accuracy And Changing Treatment
Approximately 300 men were enrolled in the Australian trial, all with newly diagnosed localized prostate cancer , and all were considered to have high-risk disease. For all men in the trial, the planned treatment was either surgery or radiation therapy to the prostate only.
Half the men were randomly assigned to initially undergo a CT and bone scan, and the other half to PSMA PET-CT.
Based on the imaging, PSMA PET-CT was 27% more accurate than the standard approach at detecting any metastases . Accuracy was determined by combining the scans sensitivity and specificity, measures that show a tests ability to correctly identify when disease is present and not present.
PSMA PET-CT was more accurate for both metastases found in lymph nodes in the pelvis and in more distant parts of the body, including bone. Radiation exposure was also substantially lower with PSMA PET-CT than with the conventional approach.
The trial investigators also tracked how imaging results influenced clinicians treatment choices. Based on imaging findings, the initial treatment plan was changed for 15% of men who underwent conventional imaging compared with 28% of men who underwent PSMA PET-CT.
Another key finding, Dr. Hofman noted, was that PSMA PET-CT was much less likely to produce inconclusive, or equivocal, results .
Thats important, he continued, because if you have a scan with equivocal findings, it often leads to more scans or biopsies or other tests.
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How A Psma Pet Scan Works
A positron emission tomography scan tracks a small amount of a radioactive compound or tracer as it moves through your body.
Most PET scans use a type of sugar as a tracer. PSMA PET scans use a tracer to help pinpoint. There are two availablr, piflufolastat F 18 injection or gallium 68 PSMA-11.
It targets a protein called prostate-specific membrane antigen . You can find it on all prostate gland cells, but cancer cells have far more PSMA than normal. The tracer binds to it and lights up on the scan, even in tiny amounts. This helps your doctor pinpoint whether and where your cancer has spread.
What About The Cancer Cells That Dont Make Psma
Pomper is developing new molecules and therapies to target PSMA-invisible forms of prostate cancer. We are working on agents that work through different mechanisms and can complement the PSMA-targeted agents, he says. I believe that combining theranostics with immunotherapy, PARP inhibitors and other emerging agents in addition to further optimization of dosage, dose rate and type of isotope of the PSMA-targeting agents will be able to stave off progression of the disease for years, and that eventually, these patients will not die of their prostate cancer.
There are even wider implications, too: It took a long time, but now were seeing many exciting offshoots of our work in other forms of cancer, as well. Some pretty amazing things are happening.
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Psma Pet/ct May Have Major Impact On Treatment Of Patients With Prostate Cancer
Prostate cancer experts speaking at the 2020 Genitourinary Cancers Symposium alluded to the fact that prostate-specific membrane antigen positron-emission tomography /computed tomography scanning is more sensitive than conventional imaging for the detection of occult lesions in men with prostate cancer. The fact that PSMA PET/CT scans detect more cancerous lesions compared with conventional imaging is not controversial, and many experts think this is the wave of the future.
But the most important question is the clinical utility of this modality: will its use change practice? One of the largest studies to date, presented at the Symposium during a poster session, showed that the use of PSMA PET/CT did in fact change management in 40% to 67% of patients, depending on the scenario.1
These results are extremely encouraging. PSMA PET/CT detects more disease than widely used PET radiotracers for prostate cancer. Ida Sonni, MDTweet this quote
PSMA PET/CT significantly impacted the stage and management of patients with prostate cancer across various clinical scenarios. Its utility goes beyond the two classic clinical applications of biochemical recurrence and presurgical staging, said Ida Sonni, MD, of the David Geffen School of Medicine, University of California, Los Angeles .
Study Details
Impact Of Psma Pet/ct On Staging
Per patient, the tumour N and M stage based on the composed conventional staging was compared to the tumour stage based on the additional information of the PSMA PET/CT. Differences in observed staging frequencies were tested for independence using a Chi-square test . For both N and M staging, upstaging was defined as a change from negative to equivocal or positive, or from equivocal to positive. Downstaging was defined as a change from positive to equivocal or negative, or from equivocal to negative.
Furthermore, the level of confidence in the correct assessment of the tumour stage based on the imaging findings was defined. This was done according to above mentioned N and M staging three-category systematics. For both N and M staging, increase in LoC was defined as a change from equivocal to positive or negative. Decrease in LoC was defined as a change from positive or negative to equivocal.
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Doctors Can See Prostate Cancer Anywhere In The Body With Psma Pet Imaging
For years, one of the most powerful molecular imaging tools, positron emission tomography , has frustrated doctors when it comes to detecting prostate cancer cells. Until recently, the available radiotracers the radioactive molecules doctors use to show cancer cells on PET scans did not routinely bind to this specific type of cancer.
We would know that a patients tumor had spread since their PSA was rising, but we wouldnt know where or how much and wed have to use our best guess when planning treatments, explained Daniel Appelbaum, MD, a radiologist and nuclear medicine physician at the University of Chicago Medicine. Now, however, a new radiotracer is capable of precisely and reliably tagging prostate cancer cells anywhere in the body. UChicago Medicine is one of the first institutions in Chicago to offer the PSMA PET scan and the only institution in the city to have participated in the CONDOR and OSPREY clinical trials that helped piflufolastat F 18, also known as Pylarify , gain FDA approval. It’s exciting because it’s the single best method we now have available to visualize prostate cancer in the body, said urologic oncologist Scott Eggener, MD. Knowing the anatomic location of prostate cancer can obviously help us make smarter treatment decisions for patients.
To now be able to see this all directly on a scan is a real game-changer in the fight against prostate cancer.
How Is Psma Pet Imaging Different From Current Prostate Cancer Imaging
- Current standard technique called fluciclovine PET, involves physicians injecting patients with a synthetic radioactive amino acid.
- PSMA PET imaging is a FDA approved scan with more precise detection of prostate cancer for better treatment planning and targeted care.
- More effective in pinpointing and eliminating tumors not only in the prostate but also throughout the pelvis and the body in cases where the tumors have migrated.
- Imaging with PSMA PET was able to detect significantly more prostate lesions than fluciclovine PET in men who had undergone a radical prostatectomy but had experienced a recurrence of their cancer.
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What Is A Psma Scan
PSMA stands for prostate specific membrane antigen, which is a complex protein found in the cell walls of many types of cell, but greatly increased in prostate cancer. Radio-tracers have been developed to attach to the antigen and thus show up abnormal cells, usually related to prostate cancer. A nuclear scan can detect the radiotracers and show their location on a CT scan done simultaneously. At Garran Medical Imaging we do a Technetium scan. We have developed a much higher resolution scan adapting the latest reconstruction techniques and utilising specialised windowing. Our results are comparable with Gallium PET scans.
New Psma Probe Has Potential To Improve Patient Outcomes
MEDIA RELEASE
London, ON Scientists at Lawson Health Research Institute are the first in Canada to capture prostate cancer images using a new molecule. Known as a Prostate Specific Membrane Antigen probe, the new molecule is used in Positron Emissions Tomography scans. The probe targets PSMA, a unique molecule on prostate cancer cells, to provide highly specific images for better diagnosis and management of patient disease.
PET probes are used in imaging to correctly diagnose cancer. The probes are injected into a patient where they spread to identify sites of disease. PET scans are commonly acquired as combined or hybrid images with Computed Tomography or Magnetic Resonance Imaging . The CT or MRI component helps more accurately determine where the PET probe is being concentrated.
The most common PET probes are suitable for many types of cancer, but are not as sensitive in identifying prostate cancer. PSMA probes provide higher accuracy by targeting PSMA molecules, which are highly over-expressed on prostate cancer cells.
PSMA probes are gaining popularity across the globe. This specific probe is a molecule called18F-DCFPyL and was developed by Dr. Martin Pomper at the John Hopkins Hospital in Baltimore. Dr. Pomper, also a Scientific Advisor to Lawsons prostate imaging team, worked in collaboration with Canadas Centre for Probe Development and Commercialization to bring the probe to our nation.
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For more information, please contact: Robert DeLaet
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Early Detection Is Key
When caught early and confined to the gland, prostate cancer is highly treatable. Yet, there are aggressive forms of the disease, which is why you and your doctor must carefully weigh the benefits of screening.
The Prostate Cancer Foundation urges men to begin annual screening for prostate cancer at age 50, providing they have no prostate-related symptoms or risk factors. If you are African American, then you should begin screening at age 45. If you have a family history of prostate cancer, then you should begin at age 40. If you are 55 to 69 but have no symptoms, then speak with your doctor.
Contact the Department of Molecular Imaging and Therapeutics to learn more about PSMA PET imaging. Quality of life for prostate cancer patients has definitely improved, Dr. Osborne says. Theres no question they live longer and better with this technology.