Attending the annual San Antonio Breast Cancer Symposium–as I did again this year–is an opportunity to hear directly from researchers about some of the latest findings in breast cancer research. It’s also a window into new directions that breast cancer research is going and what we may be hearing more about over the next few years.
There’s been a lot of hype lately about precision medicine. But in breast cancer at least, we really don’t yet have true precision medicine for most patients. But there are signs that’s starting to change.
According to the National Cancer Institute, precision medicine “uses genetic information from a person’s cancer to determine a patient’s treatment with a treatment targeted to that particular genetic abnormality.” There are some targeted medications available to treat breast cancer, but they are still typically used along with surgery, radiation and/or chemotherapy rather than as less-toxic replacements for these older treatment approaches.
Maybe that’s beginning to change. Some of what we heard at the Symposium may preview an era in which breast cancer treatments will be more tailored to each individual person–whatever the stage of their disease. The hope is that patients may be spared the effects of drugs that would not work for them, while receiving treatments that are based on the specific molecular characteristics of their cancer, and thus much more likely to be effective for them.
But progress along these lines seems incredibly slow. What will it take to change this? In order to advance more rapidly toward precision medicine in breast cancer, it seems pretty clear that we’re going to need much more collaboration among researchers. And that will need to include more extensive sharing of data.
Dr. Martine Piccart, in a lecture on “Lessons learned from an expedition exploring the world of HER2 positive breast cancer,” talked about the progress so far in understanding the implications of biomarkers beyond HER2 for tailoring treatments to patients. But she suggested that many of the trials going on in this area are not being done in collaboration and the data from these trials is not routinely being shared among researchers.
The implication was that this lack of collaboration is hindering efforts to obtain answers to important research questions that will help address patients’ needs and concerns. In concluding her talk, she said:
We have seen huge therapeutic advances in HER2-positive breast cancer. We have witnessed a steep learning curve in dissecting the biological complexity of the disease. But we have yet a long way to go in order to address our patients’ needs. I hope I was able to deliver some clear messages as far as the most important tools for improved anti-HER2 treatment tailoring, but all this is still “middle-aged” research. You have understood that my dream is that one day we will agree to put all these data in a single platform. After all, these data belong to our patients.
So with that as background, what stood out among the research developments presented at San Antonio this year? Focusing on two of the major themes–developing more tailored treatments and reducing treatment toxicities–here are several studies that stood out for me.
Developing More Tailored Treatments
Here are two examples of research into new treatments where it is, or is expected to be, possible to define clearly the group of patients who are mostly likely to benefit.
Bone Health Drug May Also Improve Survival Hormone receptor-positive post-menopausal patients who are receiving aromatase inhibitors as part of their breast cancer treatment are at increased risk for bone fractures. Some patients take osteoporosis medications to reduce that risk, but older medications of this type can have significant side effects.
A newer osteoporosis medication called denosumab has been found to have similar benefits as the older drugs in reducing the risk of fractures while also having fewer adverse side effects. In addition, a study presented in San Antonio found that denosumab also improved disease-free survival in these patients. Based on these findings, the researchers recommended that denosumab be offered to post-menopausal patients receiving adjuvant treatment with aromatase inhibitors.
Immunotherapy-Who Benefits Most? The JAVELIN early phase clinical trial was designed to evaluate the safety and tolerability of avelumab, an immune system therapy. Avelumab is an anti-PD-L1 antibody. In this small trial (168 patients with metastatic breast cancer), the overall response rate, or percentage of patients receiving benefit from the treatment, was very low. However, some subsets of patients had better response rates. And in particular, patients in the trial with triple negative breast cancer who also had high levels of PD-L1 expression by immune cells within the tumor, had a much higher response rate. Avelumab continues to be investigated as a potential treatment for metastatic breast cancer.
Reducing Treatment Toxicities
It’s encouraging to hear more emphasis being placed on finding ways to reduce treatment toxicities and to intervene to limit the adverse side effects of treatments. Here are two studies that focused on reducing treatment toxicities.
When Chemotherapy May Not Be Needed There is now evidence that some patients with hormone-receptor positive breast cancer, even those with positive lymph nodes, may not need chemotherapy. An analysis of about 350 patient tissue samples from a completed clinical trail (SWOG S8814) found that it was possible to identify–using genetic biomarkers–a subset of women whose cancer was at very low risk of recurrence. The researchers concluded that, if these biomarkers are validated, it will be possible to identify patients whose prognosis is excellent with anti-estrogen therapy alone, even though they have positive lymph nodes, and who could safely avoid chemotherapy.
Reducing Adverse Effects on the Heart – Could ACE inhibitors or beta blockers (commonly prescribed heart medications) be used to prevent heart damage in HER2-positive early breast cancer patients receiving Herceptin? That is the question that the MANTICORE clinical trial sought to answer. The trial of 99 patients provided evidence that these treatments can protect certain aspects of heart functioning for such patients. The researchers said that longer-term follow-up with larger studies is now needed.
For More Information
If you’d like to read more about the findings presented at this year’s Symposium, here are several informative blog posts:
- American Association for Cancer Research – SABCS 2015: Attendees from 95 Countries Leave With Latest Breast Cancer Information
- Dr. Susan Love – CVO Report: San Antonio Breast Cancer Symposium 2015
- Karuna Jaggar, Breast Cancer Action – SABCS 2015: Who Can Skip Chemo? Looking for Answers in Molecular Signatures
Photo by Lisa DeFerrari