Development-stage drugmaker Adolor (NASDAQ:ADLR) says it plans to be ready in the third quarter to attach the jumper cables and try to get lead drug Entereg back on the road toward FDA approval.

The jolt would come in the form of submission of data to the FDA.

Development of Entereg has been halted since April, when Adolor and partner GlaxoSmithKline (NYSE:GSK) released horrible results from a long-term safety study of the drug's use to reduce the side effects of powerful pain relievers such as morphine. After the results came out, the companies stopped all ongoing studies of the drug.

Yesterday's update saying it won't be until the third quarter that Adolor can complete analyses of the studies and give the FDA the data from past studies -- which it needs to do if it wants the FDA to allow new clinical trials of Entereg -- means any clinical trial work with Entereg will begin no earlier than 2008.

Adolor was also testing Entereg for use in post-operative bowel dysfunction. The FDA gave Adolor an approvable letter for this indication in November 2006 and sought more information. Even after the failed safety study in April, Adolor had guided for submitting its response to the FDA later this year.

No updates on the timeline for the approvable letter were announced yesterday. But it really doesn't matter much at this point when the company submits its response, considering that the FDA's previous refusal to grant Entereg marketing approval in this indication was because of safety concerns.

Since Adolor's latest study doesn't appear to have assuaged these concerns (in fact, it actually raised new ones), it's nearly impossible to see how the FDA could change its stance on Entereg without new clinical studies. The FDA's request for more data before Adolor and GSK will be able to initiate new studies of Entereg will further delay the studies. If the FDA even allows new clinical trials with the drug, it will likely be many years before the compound could be on the market. 

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. GlaxoSmithKline is an Income Investor recommendation. The Fool has a disclosure policy.