Drug Duo May Help Fight Aggressive Form of Breast
TUESDAY, Jan. 17 (HealthDay News) -- Combining two drugs that
target an aggressive type of breast cancer known as HER2-positive
appears to work better than using either drug alone, researchers
The dual-drug approach greatly boosted the chances of
eliminating microscopic signs of early cancer by the time a woman
was due to have surgery, said researcher Dr. Jose Baselga, chief of
hematology/oncology at Massachusetts General Hospital Cancer Center
and a professor of medicine at Harvard Medical School.
The study was published online Jan. 17 in
The two drugs are Tykerb (lapatinib) and Herceptin
(trastuzumab). Using both together resulted in a 51 percent
response, compared with a 30 percent response in women given
Herceptin alone. Those given Tykerb alone had a 25 percent
"What we observed was a massive improvement in response," Baselga said.
GlaxoSmithKline, the maker of Tykerb, helped fund the study.
"Lapatinib was approved for advanced breast cancer in 2007," Baselga said. "The question we had was, what is the efficacy if we give it in early-stage breast cancer prior to surgery?"
Baselga and his colleagues conducted a trial treating 455 women
from 23 countries. All had HER2-positive breast cancers. All had
tumors larger than about three-fourths of an inch.
In HER2-positive breast cancer, test results are positive for a
protein called human epidermal growth factor receptor 2, which
promotes cancer cell growth.
In the study, 154 women got Tykerb, 149 Herceptin and the other
152 both drugs. All had the drug regimen before surgery, with Taxol
(paclitaxel), a standard chemotherapy, added after six weeks. After
12 more weeks of treatment, the women had surgery.
At that point, researchers evaluated who had better responses.
The women continued the treatments for one more year, allowing
researchers to follow them and see how the approaches affected
Baselga stressed that the study looked only at women with
early-stage HER2-positive breast cancers, and that the drug Tykerb
is approved now only for advanced breast cancers.
The study is well done and important, said Dr. Len Lichtenfeld,
deputy chief medical officer for the American Cancer Society. The
two drugs, he said, "affect the same pathway but do it in a
While the combination showed a better response rate, "there is
also an increased level of side effects," he noted.
While no major heart problems occurred, those on Tykerb alone or
the two-drug combination had more diarrhea. Liver-enzyme
alterations were also more frequent when Tykerb was used.
GlaxoSmithKline notes that liver toxicity with the drug may be
severe and that deaths have been reported, although the cause of
the deaths has not been determined.
The important question, however, has not been answered yet,
Lichtenfeld said. That's the effect on overall survival in using
the two-drug approach. The researchers are continuing to evaluate
Cost is another consideration: Tykerb runs about $4,000 a month
wholesale, and retail prices could be higher.
In another study, published online Jan. 17 in
The Lancet Oncology, researchers from Germany reported that Tykerb is less beneficial than Herceptin as a single-drug therapy.
They assigned 620 women with HER2-positive breast cancer to get
standard chemotherapy plus Herceptin or Tykerb.
They looked to see which drug was better at eliminating invasive
cancer in the breast and metastatic cells in the lymph nodes. While
30 percent of those in the Herceptin group had this response, 23
percent of the Tykerb group did. The study was funded by drug
makers GlaxoSmithKline, Roche and Sanofi-Aventis.
Baselga reports receiving honoraria from Roche; other co-authors
report receiving speaking fees or honoraria from GlaxoSmithKline
and fees from other drug companies.
To learn more about breast cancer, including HER2-positive
cancers, visit the
American Cancer Society.
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