ATLANTA - Women with advanced breast cancer soon might have another treatment option: A novel experimental drug delayed the growth of tumors nearly twice as long as standard chemotherapy did in patients who had stopped responding to Herceptin, doctors reported Saturday.
The drug, Tykerb, worked so well that an international study of it was stopped early, in March, and all participants were offered the drug.
In the study, women who received Tykerb plus the chemotherapy drug Xeloda had no tumor growth for an average of 8 months. That compares with 4 months for those given only Xeloda, said Dr. Charles Geyer Jr. of Allegheny General Hospital in Pittsburgh.
He led the study and reported results Saturday at a meeting in Atlanta of the American Society of Clinical Oncology.
Tykerb's manufacturer, British-based GlaxoSmithKline PLC, paid for the study and said it would expand global access to the drug under compassionate use provisions. The company plans to seek approval to sell Tykerb in the United States and elsewhere later this year.
"This is huge," said Dr. Roy Herbst, a cancer specialist at the University of Texas' M.D. Anderson Cancer Center in Houston, who had no role in the study but has consulted for Glaxo in the past.
"The next step will be to use it in patients instead of Herceptin up front," to see whether it is more effective, he said.
Herceptin and Tykerb are members of a new generation of cancer medicines that more precisely target tumors without killing lots of healthy cells. Herceptin has been an important option for many women with advanced breast cancer, but eventually it stops working.
Like Herceptin, Tykerb targets a protein made in abnormally large quantities in roughly one-fourth of all breast cancers. Herceptin blocks the protein on the cell's surface; Tykerb does it inside the cell and blocks a second abnormal protein, too.
Summary: A study of 321 women with breast cancer compared experimental drug Tykerb with standard chemotherapy drug Xeloda. Tykerb proved so effective that the study was stopped early so all participants could use it.
Delay in growth: Women using Tykerb in addition to Xeloda had no growth of their tumors for an average 8 months, compared with 4 months in women taking Xeloda alone.
Spread to brain: Cancer spread to the brains of 15 of the 160 women in the Xeloda group; that compares with only four of 161 women in the Tykerb group.
Side effects: Diarrhea, mostly mild, and rashes were more common in women taking Tykerb. Four of the 160 on the drug combination had a modest decrease in pumping power of the heart's main chamber.
- Associated Press