One of the papers presented during yesterday afternoon’s plenary session at the annual meeting of the American Society of Clinical Oncology (ASCO) captured my attention for a couple of reasons.
The study reported on a new drug code named BSI-201 in a trial where the researchers treated women with a form of breast cancer called “triple negative.” Triple negative breast cancers (or TNBC) are called that because they don’t have estrogen or progesterone hormone receptors and are negative for a genetic marker called HER2. As a result, they can’t be treated with some of the more successful breast cancer treatments such as hormonal therapy or targeted drugs such as trastuzumab (Herceptin ™), They tend to occur in younger women and especially in African American women. Unfortunately, they tend to be more aggressive than other forms of breast cancer.
This new drug acts against something called poly(ADP-ribose) polymerase-1, or PARP-1. If you think that is a mouthful and don’t understand what it is, don’t feel bad. Neither do I and neither did much of the audience at yesterday’s presentation. In fact, this was so new to the doctors in the audience that they had a special tutorial in PARP-1 before they presented the data from the paper, so everyone could learn something about the science behind the drug. Basically, this enzyme is involved in gene repair and cell proliferation, two key targets to control cancer cells. BSI-201 inhibits PARP-1, and it is thought that it works best by adding it to certain chemotherapy drugs as opposed to using it by itself.
In this trial, women with TNBC with metastatic disease—a particularly difficult situation to treat—received chemotherapy with two drugs (gemcitabine and carboplatin). Half the women received just the chemotherapy, and the other half received the drugs with the addition of BSI-201.
The results, in my opinion, were impressive: 62% of the women who got BSI-201 responded to the treatment compared to 48% in the “control” group that got just the standard therapy. The time it took for the disease to progress on treatment in the women who received BSI-201 was 6.9 months, compared to 3.3 months for the women on the standard treatment arm. The overall survival increased from 5.7 months in the control arm to 9.2 months in the BSI-201 arm. There was no apparent increase in side effects from adding BSI-201 to the treatment program.
Those improvements are all significant, although obviously don’t represent the types of increased survivals we would like to see. But as I mentioned, women with TNBC who have metastatic disease unfortunately don’t do well with current treatments, and this new drug represents a true ray of hope in a frequently hopeless situation. I would also note that some of these women had already received prior chemotherapy, which in effect stacked the deck against seeing any success with this new drug regimen.
I was so intrigued by the results that I tried to find out more about the company that invented the drug. The name of the company is BiPar Sciences. You would think that this would be a large company to have made such a significant discovery of a drug that represents an entirely new class of therapy.
What I found out was that in fact the company had recently been purchased by a larger pharmaceutical company, so it is no longer a “stand alone.” I also was told that the company still pretty much works on its own, free of much of the constraints that usually come along with being part of a much larger organization. The number of employees who worked on this exciting discovery and clinical trial? About 20, according to my source.
And, on another front, it appears that this clinical trial was done in large part through member practices of US Oncology, a nationwide oncology practice organization, not through a major university or university consortium. So it reinforces the fact that private practices (and their patients) that commit to clinical cancer research can make significant contributions to advancing our knowledge and capabilities in cancer care. If we could see more of this type of commitment and participation by non-academic, community based oncologists we could dramatically increase access to clinical trials and get more cancer drugs tested nationwide.
So here we have one of the more exciting advances in chemotherapy that I have seen in a while, and it didn’t take a giant company or major universities to get the job done.
For women with TNBC there is now a bit more hope that we can help them in their time of need. The trial reported here at ASCO was what we call a phase II trial, which is essentially early stage proof-of-concept. The next step is a phase III trial, which will treat more women, and that is scheduled to start this month. The drug is also under investigation in other cancers as well.
Here's hoping that this research opens the door to a new and exciting frontier in cancer research and cancer treatment. It clearly looks that way to me.