The Real MTP Story: From The Inside

The Real MTP Story: From The Inside


Leonard Zwelling

I was a witness to scientific history. Someday, that history will be written in the textbooks. But not yet.

As this perceptive op-ed from The Washington Post demonstrates, muramyl tri-peptide encapsulated in a lipid delivery vehicle (liposome) is an immunostimulant that activates macrophages to kill cancer cells, especially those that have metastasized to the lungs. I should know. I was a witness to the initial presentations about the discovery by Dr. Isaiah Fidler and the development of the drug in people with osteosarcoma by my wife Genie Kleinerman with the help of Irv Krakoff and Norman Jaffe. All the numbers documenting the drug’s efficacy in this piece are correct.

Yes, osteosarcoma is a rare tumor. There are about 1000 cases per year in the U.S. Yes, a majority can be cured with local resection and combination adjuvant chemotherapy. But not all. And the ones with disseminated disease at presentation (about 10%), or recurrence after systemic therapy, or residual active disease do not have a good prognosis. The immunostimulant MTP increases the survival rate among these patients. All of this is outlined in the Post article along with the outrage of patients having to jump through hoops to gain access to the drug off-shore because the FDA blocked the drug’s approval in the States, mostly because of the actions of a single official at the agency and the unwillingness of MD Anderson alumnus Rick Pazdur to overrule her. Too bad. Fortunately it is approved all over the world and thus accessible to American patients with the wile and guile (and money) to get it through a compassionate FDA mechanism.

MTP was developed here using American taxpayer money, but it is easier to get in China than in Nebraska. BUT, here’s the real tragedy.

While it is indeed true that there would be perhaps a few score of people in America with osteosarcoma per year who might benefit from liposomal MTP, what about all of those patients with other malignancies who have never had access to the drug because there has been no off-label use of it in the States, the place where off-label use is a critical contributor to the battle against cancer? In other countries, off-label use, use in diseases against which the drug has yet to be tested, cannot occur. The health systems won’t approve it. Here that’s not true. Once a drug is approved, any doc can prescribe it for anything. That’s how the checkpoint inhibitors have come into such wide usage for a number of cancers. The same might be true for MTP. But if it is not approved here, we will never know. That’s the real tragedy of the MTP story.

Do I have a vested interest in the drug being approved? You bet! Is it financial? Not a chance. Neither my wife nor I have one share of drug company stock that would benefit from MTP’s approval. We never have. It just seems to me that a drug that migrates to the reticulo-endothelial system would go to the liver and might be a great adjunct to the treatment of locally advanced colon cancer to prevent death from liver mets.

The young woman who wrote this piece has it absolutely correct. But it’s only a piece of the story. The real story is that Drs. Fidler, Kleinerman and Jaffe never did get the credit they deserve for altering the natural history of a potentially lethal cancer. But their surviving patients know. For now, that’s enough. But this shouldn’t be the end of the story.

Now on a more personal note, if that’s possible, there are only a handful of MD Anderson faculty who have developed a treatment for cancer on their own or with a research team. Perhaps none has received less notoriety for their work at their home institution than has Dr. Kleinerman. Am I pisssed about this? Yes, I am. Am I part of the problem? Probably. My writing of this blog and in the Cancer Letter and elsewhere during the DePinho years undoubtedly put her in poor favor with the reigning megalomaniac of that moment. But that moment is over and it’s not too late. Let’s give credit where credit is due. Both Kleinerman and Fidler have saved the lives of real people. MD Anderson—take note! The rest of the world already has.

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