LONDON — Pharmaceutical company GlaxoSmithKline PLC reported positive results from the trial of its breast cancer drug Tykerb on Monday and said it will file for regulatory approval of the drug in the second half of this year.

Glaxo also said that it will form a strategic alliance with biotech company Sirna Therapeutics Inc. to develop gene-based treatments for respiratory diseases. The multiyear agreement could result in milestone payments of more than $700 million to Sirna.

Both stocks rose on the news.

Glaxo, which has its U.S. headquarters in Philadelphia and North Carolina, said that it had canceled enrollment in its Phase III Tykerb clinical trial after discovering an interim analysis of 321 patients in the study yielded "statistically significant results."

Tykerb is an orally taken drug intended to treat breast cancer, and is expected to compete with Genentech Inc.'s Herceptin, which must be given intravenously.

"We are extremely encouraged by these data which suggest that Tykerb may offer significant benefit as an oral medication in combination with chemotherapy for patients with advanced or metastatic ErbB2 positive breast cancer, and whose disease has progressed on previous treatment regimens, including Herceptin," said Paolo Paoletti, senior vice president of the Oncology Medicine Development Center.

"On the basis of this and other data we now plan to file in the U.S. and Europe during the second half of 2006," he added.

Glaxo had originally planned to start three Phase III clinical trials for the drug in 2006, and had not outlined a filing date.

Separately, Glaxo announced its agreement with Sirna, whose shares jumped 89 cents, or 13 percent, to close at $7.63 on the Nasdaq Stock Market. U.S. shares of Glaxo rose 53 cents, or 1 percent, to close at $52.84 on the New York Stock Exchange.