FDA-caused drug approval delays are never something for a drugmaker to be overjoyed about, but at least GlaxoSmithKline's (NYSE:GSK) investors have a better idea of how long the wait will be. On Monday, the drugmaker announced that a vaccine highly important to its future likely won't need new clinical studies before it gets approved.

The drug in question is Glaxo's human papillomavirus (HPV) vaccine, Cervarix, which protects against some types of HPV that can lead to cervical cancer. It is already approved for marketing in the European Union and multiple other places around the world. Glaxo first filed a marketing application to bring Cervarix to the U.S. in early 2007, but the FDA decided late last year that it needed more information.

Yesterday, Glaxo announced it had answered all of the FDA's worries. The catch is that Glaxo will wait until the first half of 2009 to give the FDA additional data from an ongoing study.

Cervarix will undoubtedly be subjected to the longer "type 2" approvable-letter review after Glaxo submits its approvable-letter response next year. This means that the FDA will likely take another six months after the submission before making another approval decision on the vaccine.

Cervarix approval in the European Union occurred in late 2007. Sales of the compound throughout the world reached $24 million in the first quarter, although in many places this is still very early in its marketing launch.

This is only a small fraction of what Cervarix could have brought to Glaxo's coffers had it been approved in the U.S. as well. Sales of Merck's (NYSE:MRK) competing HPV vaccine, Gardasil, hit $1.5 billion last year and Gardasil's sales growth is still gaining, with sales up 7% year over year in the first quarter, although Gardasil has recently seen FDA setbacks of its own.

Vaccines are the bedrock supporting multiple drugmakers, including Wyeth (NYSE:WYE) and Sanofi-Aventis (NYSE:SNY). While it's unfortunate for Glaxo that it will have to wait until at least mid- to late 2009 to see Cervarix on the U.S. market, Glaxo did receive positive FDA news for some of its other vaccines last week, and its vaccines division is performing quite well overall.