Shares of Guilford Pharmaceuticals Inc. climbed Thursday after the company announced that it would resume clinical trials of a sedative developed at Kansas University and refined by a Lawrence-based spin-off.

Guilford’s stock closed at $2.47, up 18 cents — nearly 8 percent — after the company said that it had agreed with the Food and Drug Administration on a “focused clinical development” strategy for its Aquavan sedative.

Guilford intends to file its new drug application with the FDA during the second half of 2006, said Dean Mitchell, Guilford president and CEO. The number of trials will be reduced from 13 to five, and include a dose-range study involving colonoscopies.

“We believe that this less-complex clinical trial plan increases the probability of FDA approval within an optimal time frame,” Mitchell said.

The announcement came five weeks after the company said it had voluntarily stopped enrolling patients in its Aquavan trials, a move that sent shares down nearly 34 percent, to $2.34.

Last month, Baltimore-based Guilford reported that while late-stage trials on 278 patients undergoing colonoscopies had met goals for effectiveness, patients receiving Aquavan had experienced a “deeper sedation” than others who had received a standard treatment. Such sedation had led to an unspecified “higher level of adverse events.”

Aquavan was created through the Higuchi Biosciences Center at KU and developed by ProQuest Pharmaceuticals Inc., a Lawrence-based spin-off. In December, Guilford announced it was buying ProQuest for $7 million in stock.

Guilford wants to market Aquavan for use in colonoscopies and other brief diagnostic and therapeutic procedures.