Terra Sigillata

Breast Cancer Cure from Dirt?

Perhaps not a cure but certainly another critical tool in the anticancer armamentarium.

If you’ve ever read our introduction to the left in my profile as to why this blog is called Terra Sigillata, you’d know that the first trademarked drug was dirt itself (or soil to be exact). Terra Sigillata was a special fatty clay harvested from the Greek isle of Lemnos and then punched into planchets with a special seal. Because it contained kaolin, a component of Kaopectate, it was useful for treating gastrointestinal disorders, and its high mineral content was useful for treating deficiencies that were common in the day (around 500 B.C.).

Well, the soil has given us a new compound whose semi-synthetic derivative is about to be reviewed for approval by the US FDA’s Oncological Drugs Advisory Committee (ODAC).

The drug is called ixabepilone (ix-uh-BEP-i-lone) and is derived from a class of compounds called epothilones. Epothilones were first isolated from a soil-dwelling bacterium called Sorangium cellulosum (a myxobacterium for those interested). The beauty of epothilones is two-fold: they stabilize the microtubules of cancer cells much like other breast cancer drugs such as Taxol/paclitaxel or Taxotere/docetaxel; however, they are more potent than these “taxanes” and still kill breast cancer cells that have evolved to develop resistance to taxanes.

So, in women with breast cancer for whom Taxol or Taxotere no longer works, ixabepilone might be another life-prolonging option. The proposed trade name by the corporate developer, Bristol-Myers Squibb, would be Ixempra. (For basic science and translational oncology readers, the compound has also been known in the literature as BMS 247550).

The Health Blog of the Wall Street Journal has a little more on the business side of this remarkable class of compounds.

Let it suffice to say that those of us in academic natural product research would be tickled to see ixabepilone approved.


  1. #1 bezenfield
    October 16, 2007

    Great story about terra sigillata. I have to sheepishly admit to never reading your sidebar 🙁

    As breast cancer patients are living longer with new therapies it’s still important to have other choices – ixabep sounds quite promising.

  2. #2 PharmCanuck
    October 17, 2007

    Of course, this isn’t the only useful cancer drug from dirt. After the discovery of the anti-tumour effects of the antibiotic Actinomycin D, interest was sparked in the isolation of other anti-cancer agents from microbial sources. In Italy in the 1950’s, Farmitalia Research Labs, in the search for new agents, isolated a new strain of the soil bacterium Streptomyces peucetius. Their work with this strain ultimately led to the isolation of daunorubicin and doxorubicin (Adriamycin).

    Isn’t it interesting how old ideas become new again!

  3. #3 Abel Pharmboy
    October 17, 2007

    Indeed, PharmCanuck. As I recall, the culture of S. peucetius you describe came from a 13th century castle on the Adriatic Sea, leading to the name Adriamycin and the subsequent pharmaceutical company, Adria.

    Digging in the dirt even further (pun intended), Streptomyces have proven to be a rich source of anticancer and antibiotic compounds.

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