"Many patients with platinum resistance are still sensitive to taxol," he says, "so we use it for patients who have this resistance or who develop a relapse right after the platinum-based treatment."

Ongoing studies by Cannistra and researchers around the country are, however, testing the effectiveness of taxol as a possible first-line therapy. And initial results seem promising.

Cannistra says the results of the trial indicate that the response rate to the taxol-containing treatment is 79 percent, while that to the standard non-taxol treatment is 63 percent.

"Because of that difference," says Cannistra, "we think that taxol may play a more important role in the treatment of newly diagnosed patients. Whether increased responsiveness will overall translate into better survival will require long term results."

At this time, the FDA has only approved taxol for treatment of ovarian cancers after other treatments have failed. But at least one physician hopes this will change.

"I think it should be used as first line, but it is very expensive and supplies are limited," says Dr. Mussa Banisadre, medical director of the California Cancer Center. "Within the next few years we'll see taxol as a first-line treatment for breast cancer, but I don't think it will be used as a first-line treatment for ovarian cancer."

Even were taxol to become a first-line treatment, scientists concede that it would be better used in combination with other anti-cancer drugs. "I don't think anyone will ever use [taxol] alone knowing that the combination chemotherapy is the only way patients have been cured," says Ayash.

"Our experience shows that whenever you use a single drug it's not as effective as if you combine it with other active drugs," agrees Banisadre. "Eventually resistance develops because not every cancer cell behaves the same as the next one."

With all the information provided by recent studies, Jacobsen says the hope and optimism regarding taxol has decreased significantly since its first isolation in 1971.

"It was once considered a wonder drug," he says. "Now people are more calm about the prospects because some of the trials that have come back indicate that taxol is not as effective as once thought."

Scientists, says Jacobsen, will need to take advantage of what nature has inadvertently given them.

"This is a molecule that a tree makes," says Jacobsen. "A tree isn't trying to cure ovarian cancer, but it has given us a great clue as to what might work."