Irv Weissman on the many barriers to stem cell therapies and why they matter

Stem cell pioneer Irv Weissman has a rather feisty correspondence in the June 14 issue of Cell Stem Cell in which he takes issue with the many barriers standing in the way of stem cell therapies. His targets include fraudulent stem cell clinics, lack of Food and Drug Administration oversight, private cord blood banks, lack of biological models of how diseases progress, bad science, and problematic business development practices. To name a few.

So comprehensive is his list of guilty parties that he writes, “So, whom have I failed to annoy here?” Pretty much nobody, Irv.

Weissman, who directs Stanford’s Institute for Stem Cell Biology and Regenerative Medicine and has several CIRM awards, became the first person to isolate a stem cell when, in 1988, he identified the stem cell in the bone marrow of mice that can reform the entire blood system. (There’s a great profile of this discovery here.) The reason for his frustration regarding the future of the field he helped found stems, surprisingly, from optimism. He writes:

I fear that therapies using purified tissue and organ-specific stem cells—the only self-renewing cells in a tissue or that can regenerate that tissue or organ for life—will remain elusive. Before I go further, just think about that statement: regenerate that tissue or organ for life. No pharmaceutical, no biotech-developed protein, and no other transplanted cells can do that. If we can deliver purified stem cells safely and effectively as a one-time therapy, we can change medicine, especially for diseases that drugs and proteins can’t touch. Moreover, if we manage the costs and charges carefully, this form of therapy could lower overall health care costs dramatically. This vision is based on solid scientific evidence that stem cells regularly maintain, and, if necessary, regenerate tissues in a homeostatically controlled process. So it’s worth the extra effort to find a way to make it happen.

The one group that failed to draw Weissman’s wrath was CIRM, thank you very much. He wrote:

The largest and best funding experiment I have seen so far comes from the California Institute for Regenerative Medicine. CIRM’s charter allows it to fund promising stem-cell-based discoveries to and through phase I trials, taking out the risk that leaves our field bereft of suitable funds and in the “valley of death.”

Weissman has one of the awards he praises—the so-called Disease Team Awards. His is aimed at developing a therapy for leukemia. The next round of these awards are due to be voted on in July.

He ends with a reminder of why he is so eager to see the barriers to stem cell therapies overcome, and to see the promise of the field be fulfilled:

Remember, right now our patients, friends, and families are contracting diseases that have a very short window of opportunity in which regenerative therapies can save them, and each delay removes a cohort of them from possible cures. We should not fail them.

A.A.