Astra drug keeps lung cancer from worsening: study

ORLANDO, Florida (Reuters) - AstraZeneca PLC's Zactima, which failed two earlier trials, was shown in a pivotal study to extend the amount of time patients survived without their lung cancer worsening, researchers said on Saturday.

Anglo-Swedish AstraZeneca plans to file for U.S. regulatory approval of the oral drug, also known as vandetanib, by the end of June.

The trial, called Zodiac, involved 1,391 patients with advanced non-small cell lung cancer whose disease has worsened after chemotherapy. It also found that almost twice as many patients treated with a combination of Zactima and chemotherapy drug docetaxel had shrinkage of their tumors, compared with those given just chemotherapy.

Median "progression-free" survival for the group on the combination therapy was 17.3 weeks, compared with 14 weeks for the chemotherapy-alone patients, according to the study, which was presented here at the annual meeting of the American Society of Clinical Oncology.

The results also showed "a trend toward advantage in overall survival," in patients who were "quite sick, quite symptomatic," said Peter Langmuir, medical science director at AstraZeneca.

DOUBLE MECHANISM OF ACTION

Like Roche Holding AG's Avastin, Zactima is designed to block the vascular endothelial growth factor, which tumors need to develop a blood supply. The Astra drug also targets the vascular epidermal growth factor receptor, the same protein blocked by drugs like Tarceva, a product of Roche and OSI Pharmaceuticals Inc.

A separate trial presented at ASCO showed that a combination of Tarceva and Avastin reduced by 29 percent the risk of disease progression compared to Avastin plus a placebo.

The study was designed to test Tarceva as a so-called maintenance therapy to help delay progression of the disease following successful chemotherapy treatments.

"Here you have it all in one pill," said Dr. Roy Herbst, chief of thoracic medical oncology at the University of Texas M.D. Anderson Cancer Center and the author of the Zactima study. "To my knowledge, this is the first instance in second-line therapy where another therapy added to docetaxel showed a benefit."

Analysts have estimated eventual sales of the drug at around $500 million.

Although Zactima did not dramatically increase progression-free survival in the trial, the fact that the drug improved symptoms is very important, Dr. Herbst said.

"Clearly patients are progressing less quickly, but unfortunately they are all going to succumb to their disease," he said. "We were able to show that with the increased time for patients' tumors to grow, they were reporting that they were feeling better."

AstraZeneca said efforts to determine which patient groups were most likely to respond to its drug have so far had little success.

Langmuir said Zactima adds rash and diarrhea to the list of side effects seen from chemotherapy, but patients have less nausea, vomiting and anemia.

Results from a fourth trial studying Zactima as a stand-alone treatment after the use of Tarceva and other drugs are expected later this year.

A previous trial, also presented at ASCO, showed that the Astra drug works at least as well at Tarceva.

Lung cancer kills 1.2 million people a year and is the top cause of cancer death globally. Many drugs are used to treat it, but they almost always stop working eventually.

Langmuir said Astra is currently exploring a number of development options for Zactima as a first-line lung cancer therapy and in maintenance settings.

(Reporting by Deena Beasley, editing by Matthew Lewis)