First clear signs that CAR-T treatment may work in advanced prostate cancer

As regular readers will be aware, we rarely comment on the earliest signals that investigational treatment X or Y might turn out to have value in the treatment of prostate cancer. There are way too many such early signals, and most of them come to naught. But there are exceptions to all general rules.

The Prostate Cancer Foundation has been holding its annual scientific retreat in Washington, DC, this week, and one of the more exciting sets of data presented relate to very early signals that CAR-T immunotherapy may turn out to be applicable for at least some patients with progressive and advanced forms of prostate cancer.

According to a media release issued by the developing company, a specific form of this type of therapy, using a molecule currently known only as P-PSMA-101, has been shown to have “potent anti-tumor activity, a persistent and durable response, and no T-cell exhaustion observed” in a laboratory model of prostate cancer. Furthermore, the developers claim that this study has shown that P-PSMA-101 CAR-T cell therapy “could completely eliminate solid tumors in a previously incurable preclinical model of prostate cancer.”

P-PSMA-101 has been developed by Poseida Therapeutics and is the company’s primary PSMA-specific chimeric antigen receptor T cell (CAR-T) stem cell memory drug candidate (as of now).

However, let us be extremely clear that: (a) this study has shown only that this type of CAR-T therapy worked in cell lines in the laboratory; (b) no one has given this type of therapy to a man with prostate cancer as yet. It is therefore scientifically interesting, but still a long way from becoming available as a clinical treatment for men with advanced forms of prostate cancer.

On the other hand, CAR-T is showing signs of revolutionizing the treatment of some forms of cancer, and it has been associated with the ability to actually put patients with severe forms of some cancers back into long-term remissions. And from that perspective, this type of therapy is clearly of interest to the prostate cancer community.

Just 5 weeks ago, the US Food and Drug Administration (FDA) approved the very first form of CAR-T therapy, with the approval of a drug known as tisagenlecleucel (Kymriah) for the treatment of certain pediatric and young adult patients with a form of acute lymphoblastic leukemia (ALL). The potential of CAR-T therapies in the treatment of at least hematologic or blood cancers is real. Hopefully, it will prove to be real in prostate cancer too.

2 Responses

  1. CAR-T

    This is the first promising new treatment I’ve seen that “could” help my husband, battling Stage IV metastatic prostate cancer. He was diagnosed 5 years ago this month. He’s gone through 40 rounds of radiation, four different chemo drugs, Xtandi, Zytiga, docetaxel and cabazitaxel (Jevtana) along with Provenge and Lupron injections every 6 months — not to mention Flomax, Lasix; potassium, twice a day since this past March. Many other issues arose. After the third cabazitaxel treatment he started having severe hallucinations. Now, he sleeps a lot; eats a little but at least twice a day — snacks; but – not doing so good. Hoping that the FDA will hurry up with this one — as time for my husband appears to be running out.

  2. Dear Ellen:

    And I hope that someone can develop a form of treatment that can reverse prostate cancer progression soon too (as I am sure do many of our readers), but the FDA doesn’t develop new forms of treatment. That’s up to the drug developers (in academia and at commercial companies).

    The speed at which the FDA has been approving new forms of treatment for specific forms of cancer over the past 5 years has actually been astonishing — but they do need studies to be done to show that these new drugs are both effective and safe … and it is doing those studies that takes the time. The paperwork (by comparison) can be done very fast.

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