Cancer Stem Cell Drug PRI724 IND filed September 17

Dr. Michael Kahn and Dr. Heinz-Josef Lenz

Dr. Kahn and Dr. Lenz in Their Lab

I have shared with you in the past the efforts of Dr. Michael Kahn and myself to develop novel drugs which are completely different than the existing ones.

Even the smart drugs we have such as Avastin or Erbitux, which are monoclonal antibodies that attack important targets in cancer growth and progression, have disappointed,  particularly if you are not able to select the patients who benefit the most.

Why are they not more effective?

The communications hot lines in cancer cells are extremely complicated and look like a subway/bus/tram network of large cites. Do you think when you knock out one even major intersection; it will be lethal to the city?

No. Annoying it may be, but we all know detours and ways to avoid these problem spots and so does the tumor. In fact tumor systems often  have backup communication lines which can handle these attacks.

So what do we need to do? We cannot shut down one exit or one intersection we have to shut down major lines (red, purple whatever), which are essential to maintain traffic. In cancer biology we call those major lines pathways.

Dr. Kahn has developed a novel drug which shuts down one of the most important pathways in colon cancer called Wnt (pronounced wind). This drug has shown tremendous potential to treat many cancers including leukemia and even noncancerous disease such as pulmonary fibrosis.

On September 17, 2010 we filed  an Investigational New Drug application to the FDA, which means we want approval from FDA to test this drug for the first time in patients. We expect that the trial will open in October or November.

We are very excited because this drug not only shuts down this important Wnt pathway, it also is effective treating colon cancer stem cells, which has not been possible in the past.

We all know when we treat colon cancer patients with metastases that the first chemo works usually the best, the second shorter, and with the third there is little chance. We all think this is due to the cancer adapting to the chemotherapy. However we think it is that these tumors are getting enriched with stem cell like cancer cells which are, by definition, resistant to chemotherapy. With this drug we can change that.

But this is not the best news. This drug has so far no shown any side effects, even when tested at 250 higher concentrations than needed. Obviously we need to await the clinical data but we are very excited.

USC is so excited that they gave us permission to create a new center called USC Center for Molecular Pathways and Drug Discovery because we have other hits and leads to develop and want to do it as fast as possible.


  1. Kate Murphy says

    It’s hard for us to answer your question, not knowing all the medical background.

    We suggest that you contact the person at the University of Southern California Norris Cancer Center who coordinates clinical trials there.

    Dr. Ester Sie
    Study Coordinator
    Email Dr. Sie

  2. teresa says

    My father has stage 4 colorectal cancer with mets to liver and lungs. It is now getting aggressive after 2 years of treatment and surgery on bowel and liver. Would he be a candidate?? I am desperate!!

  3. texx says

    Thank you so much Dr. Lenz for clarfying my concerns. My uncle is at Satge IV colon cancer. I don’t know how much longer he can live. I am also a biologist, but know nothing about cancers. This is why I went over DR. Kahn’s and others’papers to learn about cancer stem cells. Anyway, for your opinion, what are the best clinically defined biomarkers for colon cancer stem cells which you confidently say those are colon cancer stem cells? Thank you so much for answering my questions. I really hope my uncle can get a chance.

  4. texx says

    I have one of family members who is suffering colon cancer. I heard about this PRI-724 trial and Dr. Kahn from different sources.Then, I went through all Dr. Kahn’s publications, there are no evidences suggesting the new drug really targets cancer “stem” cells.

  5. Walker says

    How exciting! I second the other poster who asked that we be kept updated.

    One question…..would this be a treatment that would be used with chemo, like Avastin is, or would it be a completely seperate treatment?

  6. Nycole says

    Is it possible to get my father into the trial? He has stage 4 colorectal that has spread to live, lungs and pelvis. MD Anderson advised that there is nothing else that can be done. We are looking for any alterative. Would he qualify for the trial?

  7. Jennifer Weir says

    Do you know an American hero? I do. I know two.

    Dr. Kahn and Dr. Lenz are at the top in my book. I am so encouraged by the work done by these lovely men to save the lives of dads, moms, sisters, brothers, daughters, sons and friends.

    I pray they can stop heartache that colon cancer brings to so many lives.

    You are both American heros and ultimately I hope you become international heros too. I salute you!

    Thank You is to modest a statement.

    Jennifer Weir
    Stage IV cancer survivor

  8. Maritza says

    My mother has colon cancer stage 4 metastasized in liver doing second type of chemotherapy
    I will hope that she qualifies for this new approach since her prognosis is not good.

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