FDA approves first gallium-68 PSMA PET scan imaging agent in US, BUT …

Yesterday the US Food and Drug Administration (FDA) gave its approval for the first gallium-68 prostate-specific membrane antigen imaging agent (Ga-67 PSMA-11), for the use in association with positron emission tomography (PET) scanning for the evaluation of men with suspected prostate cancer — and most particularly for those men  with high-risk characteristics suggesting the possibility of metastasis, including men with newly diagnosed or recurrent disease. However, here’s the “but”…

Initially this approval has been granted exclusively to just two clinical sites here in the USA: at the University of California, San Francisco, and the University of California, Los Angeles.

The full announcement from the FDA can be found here, and a report on the MedPage Today web site may also provide useful reading for many patients.

We had been expecting approval of one of these new imaging agents soon, but this was, in fact, slightly sooner than we though possible, and the nature of the initial approval (through restriction to just two sites, both on the West Coast of the US) will be something of a disappointment to many.

Other radioactive tracer imaging agents that can be used with PET or PET/CT scans, such as F-18 fluciclovine (Axumin) and C-11 choline, have already received FDA-approved indications for use in the management of prostate cancer, but these two products have indications limited to their use in patients believed to have prostate cancer recurrence. In one of the  clinical trials leading to the approval of Ga-68 PSMA-11, this product was compared directly to F-18 fluciclovine, and Ga-68 PSMA-11 targeted scans proved able to detect significantly more prostate cancers in men who had recurrence after radical prostatectomy.

It is currently unclear exactly why the initial FDA approval has been limited to the two sites above indicated. Neither the FDA nor MedPage Today commented on this issue specifically. Our suspicion is that this may have something to do with the technical expertise and experience needed to use this type of product and the skills needed to interpret the scans. However. we hope that this new form of imaging agent will be more widely available swiftly.

According to the FD’s media release:

No serious adverse reactions were attributed to Ga 68 PSMA-11. The most common adverse reactions to Ga 68 PSMA-11 were nausea, diarrhea and dizziness. There is a risk for misdiagnosis because Ga 68 PSMA-11 binding may occur in other types of cancer as well as certain non-malignant processes which may lead to image interpretation errors. There are radiation risks because Ga 68 PSMA-11 contributes to a patient’s overall long-term cumulative radiation exposure, which is associated with an increased risk for cancer.

It may be that the limitation on the initial approval has to do with the “risk for misdiagnosis”.

We also need to make it clear that this PSMA imaging agent is not the same as the one being developed by Progenics (a division of Lantheus) properly referred to as F-18 DCFPyL but commonly known as “Pyl”. We expect that this agent will also gain FDA approval in the not too distant future. Whether it will be as effective and safe as Ga-68 PSMA-11 is still to be determined.

What we can be quite sure of is that this initial approval of the first Ga-68 PSMA imaging agent is likely to transform the work-up of men with high-risk and recurrent forms of prostate cancer over the next 5 years. The role of bone scans and CT scans may soon  be a thing of the past.

5 Responses

  1. My bigger question – why is it taking US healthcare so long to catch up on this with Europe? Years behind – I know as I traveled to Europe for my PSMA three years ago. And the Ferrotran MRI which is far more sensitive; interesting that this began as Combidex in US in 1990s. So much is wrong with prostate cancer diagnosis and treatment in US.

  2. Bluntly … because there is almost no motivation to develop products in the US once their patent life has been exhausted. We have a medical R&D model that is almost exclusively driven by for-profit enterprises, and if a product has no significant patent life it will not attract the attention of investors. Places like Australia and some companies in Europe have very different R&D models. This has NOTHING to do with prostate cancer. It is true across the medical/scientific spectrum.

  3. Can we get a list of location test centers and does insurance cover it?

  4. Dear John:

    As indicated above, the only sites currently approved to use this imaging method are those at UCLA and UCSF in California.

    Alas, I have no information as yet about whether any specific individual insurance provider will cover this test. Medicare certainly will, but what the commercial insurers will do probably depends on price and other factors.

  5. I was referred to the UCLA EAP (expanded access protocol) which is currently under way with about 2,500 new patient slots. While my previous MRI and PET/CT scans did not indicate any metastasis, the PSMA did show small lesions in other lymph nodes. This has allowed my oncology radiation team to re-evaluate the amount, location, and duration of radiation treatment in the coming months. As this scan was after the study, I had to bear the cost of the scan at $3,000.00, which was non-reimbursible thus far.

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