Excerpt
JUDY WOODRUFF (Newshour): Astounding and unprecedented aren't words you often hear from the country's leading cancer specialists, but two studies released this weekend have oncologists excited about the prospects of treatment options for people with advanced cases of the deadly skin cancer melanoma.
Two new drugs, with two new approaches, have been found to help combat the disease. One goes after a gene mutation that accelerates tumor growth. The other stimulates the immune system to fight the cancer. Eighty-four percent of those taking the gene-targeting drug were still alive after six months, reducing the death risk by 63 percent. Twenty-one percent of those taking the immune-boosting drug were alive after three years, compared to just 12 percent on chemotherapy or a placebo.
In other cancer news, a drug used to prevent recurrences of breast cancer was also found to reduce the risk of it occurring in the first place. And screening for ovarian cancer was found not to reduce the risk of dying from the disease.
Well, all of this was released at the American Society of Clinical Oncology's annual meeting in Chicago.
And to tell us more is that group's outgoing president. He's Dr. George Sledge.
Dr. Sledge, thank you for being with us.
And let me ask you first about the melanoma treatments. Do these qualify as a breakthrough?
DR. GEORGE SLEDGE, American Society of Clinical Oncology: These -- Judy, these are genuinely exciting.
I have been in this field for 30 years. During that period, the standard therapy for melanoma has been a drug that is both toxic and relatively ineffective, a chemotherapy drug called dacarbazine. It has a response rate of about 5 percent in patients with advanced disease.
One of the two drugs that you mentioned, the drug that is the inhibitor of the growth factor pathway, gives you a response rate of 48 percent. So it's nine to 10 times as effective at shrinking the tumors compared to the older therapy, so a genuine advance and genuine excitement in the field over this.
JUDY WOODRUFF: What is so different, Dr. Sledge, about the way these drugs go after the cancer?
DR. GEORGE SLEDGE: Well, our older therapies were non-specific therapies. They basically targeted cell division in the cancer cell.
The new therapies are true targeted therapies. So the BRAF inhibitor, drug that inhibits the growth factor pathway, we actually can measure a very specific mutation in patients who have melanomas in their skin. If that mutation is there, we then apply the drug that targets that mutation -- total change from how we did business 10 years ago, part of the emerging trend in cancer medicine of going after very specific molecular targets.
JUDY WOODRUFF: And is one of these two approaches more impressive than the other?
DR. GEORGE SLEDGE: Well, we don't know yet. We don't have a head-to-head comparison.
Oncologists, when they have two new drugs that improve survival -- and both of these drugs improve survival -- probably the first thing we are going to do is to combine them to see if we get even better improvement. Neither of these drugs will -- in and of itself, is likely to cure metastatic melanoma, so we will want to do novel combinations with them to see if we do -- will do better.
We will want to move these drugs up front to patients with earlier-stage disease to see whether or not something that improves survival on the one hand may actually improve the cure rate when used in an earlier stage of patients.
JUDY WOODRUFF: And why does it -- why has it taken so long to find these approaches?
DR. GEORGE SLEDGE: Well, very simply, we just didn't understand the biology of melanoma until very recently.
The mutation, for instance, that we're going after with this new drug was one that 10, 15 years ago, we didn't know existed in melanoma. This is part of the payoff for the nation's investment in cancer research over the past several decades.
We're now beginning to understand, for just about every cancer, what makes these cancers tick, and therefore, how we can interrupt the growth of these cancers.
JUDY WOODRUFF: And as you suggested a minute ago, Dr. Sledge, and I was reading today, not everyone can benefit -- with melanoma can benefit from this. There are limits to the -- to the benefits that it has.
Explain who can and who can't expect to -- to try this drug.
DR. GEORGE SLEDGE: Well, for the drug that interferes with the growth factor receptor pathway, there's a very specific mutation in the protein called BRAF. BRAF is one of the drivers of growth in metastatic melanoma.
Only about 45 to 50 percent of patients have this mutation. We can measure the mutation in the tumors of patients with melanoma. If you have the mutation, you're a candidate for the drug. If you don't have the mutation -- and this is half the patients with melanoma -- the drug simply doesn't work.
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