NEW YORK (CNNMoney.com) - Sanofi-Aventis got some good news from the FDA about one of its top-selling drugs, which won't give it much of a lift in sales but will encourage investors to buy the stock, an analyst says.

The Food and Drug Administration on Friday granted fast track review status to Taxotere, which is being reviewed for a supplemental use, the treatment of advanced stomach cancer, Sanofi-Aventis said Friday. The announcement triggered a mild increase in stock price.

The FDA grants priority review status for cancer treatments and other life-saving drugs, with the goal of completing the review process at an accelerated rate within six months. The Sanofi drug is already on the market in the U.S. and Europe as a breast cancer treatment in patients who failed chemotherapy, and as a lung cancer treatment in combination with chemotherapy.

"It's a drop in the bucket," said Gbola Amusa, analyst for Bernstein, referring to potential sales gains for Taxotere as a stomach cancer treatment. "It's helping the stock price today, but gastric cancer is not one of the biggest markets for cancer."

But Amusa said that Taxotere is a leading indicator for French drug giant Sanofi-Aventis (up $0.47 to $41.32, Research) that is closely watched by investors.

"People follow the Taxotere number very closely on the quarter," said Amusa. "When Taxotere does well, Sanofi stock price does well."

Taxotere sales totaled about $1.6 billion in 2004, behind Sanofi's top-selling Lovenox, a $2.2 billion preventative for dangerous blood clots, and Plavix, a $2 billion drug that keeps platelets from clotting to help prevent strokes.

The market for cancer drugs is expected to grow. IMS Health, the British research firm, projects that annual sales for cancer drugs will reach $55 billion in 2009, more than double the 2004 tally of $24 billion.

But Amusa said that Sanofi's "more important catalysts" for revenue growth lie outside the cancer arena. Sanofi is working on a bird flu vaccine for which it received a $100 million U.S. government contract. In addition, the company is awaiting an FDA decision on Exubera, an inhalable form of insulin, which could be announced in January. Amusa is projecting an FDA decision in February regarding rimonabant, a multiple-use treatment for heart disease and diabetes also known as Acomplia.

To read more about rimonabant, click here.