Update: Cutting-Edge Therapies For HER2 Survivors
The American Society of Clinical Oncology’s annual breast cancer symposium, held this month in Washington D.C., yielded a heavy harvest of scientific studies. And I do mean heavy.
In perusing news from the symposium at various online sites, it was all I could do to wring some practical information out of the fog of medicalese, high-level science-talk, ultra-deep single-subject dives, and a tangled thicket of acronyms. But I did my best.
And here’s what I found: new, more effective treatments for HER2 survivors may be on the horizon, if current results of several clinical trials hold true to the trials’ completion.
Twenty percent of women with breast cancer have HER2-positive cancer, which means the patient’s cancer cells have too much HER2 protein, which in turn means the cancer cells grow more quickly. Not good. HER2 cancer is more aggressive, and less responsive to hormone therapy.
Till now, treatment has been pretty much limited to chemo, and Herceptin or Tykerb, both of which kill cells with too much HER2. But Herceptin, in particular, comes with some significant possible side effects, including allergic reaction and congestive heart failure.
Now there may be hope beyond Herceptin. A team led by the Sarah Cannon Research Institute’s Dr. Howard A. Burris III has been conducting a trial in which patients with HER2-positive cancer are treated with an antibody/drug combo called T-DM1. The patients treated had stopped responding to Herceptin, and their cancer had metastasized. Burris reports that there’s been “evidence of tumor shrinkage in some patients.”
In addition, since the drug targets only cancer cells, not healthy cells, side effects are minimal. “Physicians call it a ‘smart bomb’ because it’s designed to hit the target cancerous cells with minimal collateral damage to its neighboring non-cancerous cells,” said Burris.
Dr. Burris’ colleague, Dr. Denise Yardley, presented results of two other promising studies involving new drugs for HER2-positive survivors. Both involve Herceptin in combination with other chemo drugs, and both show early promise, as well as minimal side effects.
Noted Yardley, “As knowledge about tumors and tumor biology grows, we’re learning that all breast cancers are not identical. These smart new drugs help target treatment specific to certain types of tumors, causing less damage to healthy cells and reducing side effects.”
On another front, Oncotype DX in the news again. The past several years have seen more and more women accessing the Oncotype DX test, which helps survivors with early-stage, node-negative, ER/PR-receptive breast cancer assess in advance how effective chemo might be for them, as well as how likely they are to have a recurrence. Thus far, the test has only been useful for ER/PR-receptive cancers; now, it appears that women with HER2-positive cancer might be able to use the test, as well.
The degree to which the HER2 protein is “overexpressed” (too much is manufactured) is directly tied to a woman’s prognosis; the more HER2, the worse the predicted outcome. Current methods for determining the level of HER2 have their shortcomings, including the fact that as many as 20% of readings can be incorrect, depending on which lab performs the test.
Oncotype DX’s manufacturer claims a higher rate of accuracy for its product. That higher accuracy would allow physicians to make more informed decisions about treatment—which should result in a better outcome.
Amen to that.