Nature Medicine | Spoonful of Medicine

Companies ponder how truly ‘personal’ medicines can get

By Monya Baker

personalized.jpgCancer drugs such as Herceptin are known as ‘personalized medicines’ because they are prescribed for subgroups of patients who share specific genetic traits. But truly individualized therapies are represented by treatments such as Provenge, which consists of patients’ own cells that have been extracted, exposed to an antigen that trains them to go after prostate cancer and re-infused.

The latter category is a tougher nut to crack, yet, ever since the US Food and Drug Administration (FDA) approved Provenge a year ago, cell-based personalized medicine has continued to garner interest. A course of three infusions of the treatment costs $93,000, but demand is still high. Earlier this year, Dendreon, the Seattle-based company that makes Provenge, announced it had received FDA approval to expand the number of production facilities for the product from 12 to 48.

Optimists are quick to cite Provenge as the crest of a wave of new therapies. “It has huge implications,” says Ronald Levy, a co-founder of Idec Pharmaceuticals (which merged to form Biogen Idec in 2003). “There may be 50 other therapies who hope to follow in the Provenge example.”

Although Levy, who is now at the Stanford University School of Medicine in California, is buoyant about the future of personalized cell-based therapies, he learned the hard way that some forms of personalized medicine prove too cumbersome to scale up. In the 1980s, he began creating antibodies designed for individual patients with lymphoma. Levy and his colleagues would identify telltale receptors on the wayward lymphocytes for each patient and then produce personalized antibodies designed to attack only his or her cancerous cells. Some 50 patients were treated with antibodies made this way, says Levy. “It worked most of the time, but it became economically unfeasible.” So he and his Idec colleagues instead developed the blockbuster rituximab, an antibody that targets a protein found on all B cells, allowing many patients with lymphoma to receive the same drug.

Bill Rastetter, a former chief executive at Idec and now a partner at Venrock, a venture-capital firm in Palo Alto, California, says efficacy as well as economics led him to decide against making individualized antibodies. Idec’s projected selling price for the personalized antibody approach was $50,000 per course of therapy, with about one in five patients showing remissions longer than those projected from chemotherapy alone. In contrast, about six out of ten patients benefitted from rituximab, he says, at a cost of about $10,000 per treatment course. (Levy notes that the approaches were never tested side by side, so efficacy is hard to compare.)

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Image: Jim Dowdalls/Photo Researchers, Inc.

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    Lee Buckler said:

    Great post Michelle. Thanks. As someone who has been in the cell therapy industry now for over a decade, I have thought long and hard about how cell-based therapies fit into the emerging trend of “personalized medicine” and I think your article points out an interesting irony. I would argue that although therapies like Provenge are based on a patient’s own biological raw material (cells) and there is nothing more personalized that that, on the other hand this is not a therapy designed for a particular patient subgroup who share specific genetic traits. Ergo it is not personalized medicine.

    I think what we’ve found so far with autologous cell therapies is that even though the therapy is created from the patient’s own cells there is no trending toward higher efficacy rates and conversely there is a similarly wide range of clinical responses that you would expect from other therapeutic modalities. Not unlike Levy found with his personalized antibodies, it is still important to discover what elements of “personalized” matter in terms of efficacy. I would suggest that to make a therapy like Provenge personalized would still require some matching of clinical effect to genetic traits. It is these with types of studies that I believe adaptive trial design combined with real-time theranostics might begin to show some tremendous application.

    There are a few of us advocating of late that the regenerative medicine / cell therapy industry attempt to look harder at ways we might attempt to personalize our therapies by incorporating genetics, diagnostics, and theranostics into our product development and clinical trial design but this stuff is not easy. On the other hand we have an unprecedented opportunity to leverage tools now available to us that weren’t available when previous biotech industries were in a similarly nascent stage as we find ourselves in today which means we don’t simply have to mimic their development path.

    I think there is a tremendous opportunity to create the ultimate in personally tailored medicine if we were to use a patient’s own biological materials to create a therapy based on that patient’s genetic information and then tailor the treatment regime based on data from real-time clinical theranostics (e.g., imaging). I guess on Twitter we would say that #futuremedicine is #celltherapy plus #personalizedmedicine!

    —Lee