In the wake of the disappointing news last month that Vitrase, a single injection for treating vitreous hemorrhage, did not meet its primary endpoint, ISTA Pharmaceuticals Inc. had good news to share Wednesday.

The Irvine, Calif.-based company reported that the FDA gave it the green light to proceed with the preparation and submission of clinical and other sections of its new drug application and will consider visual acuity as the primary endpoint.

ISTA’s stock (NASDAQ:ISTA) rose 52.4 percent Wednesday, or 44 cents, to close at $1.27.

“It’s fairly significant, obviously,” said ISTA CEO Vicente Anido, explaining that ISTA had “a number of discussions with the FDA” in which the company provided the agency with “top-line” information.

“They came back and said for us to go ahead and file,” Anido said, saying that there are “a number of ways to prove in studies that the drug is effective.”

Anido said the company plans to submit the clinical portion of the NDA in late summer. It submitted preclinical data to the FDA in January, but Anido said his company has made no projections regarding when a product launch might be possible.

Reiterating his “buy” rating Wednesday, Thomas Weisel analyst Don Ellis wrote in a research note that “the FDA’s acceptance of this data is the best possible scenario for ISTA as it puts the approval timeline for Vitrase back on track with our mid-2003 estimate.

“[Wednesday’s] announcement removes significant risk associated with an investment in ISTA as it demonstrates that the FDA is comfortable with the current Vitrase data and is willing to continue the approval process without requiring additional studies,” Ellis wrote.

In March, ISTA reported that two pivotal Phase III trials for Vitrase for vitreous hemorrhage failed to meet the primary endpoint of a statistically significant ability to clear an eye hemorrhage to enable diagnosis or treatment. However, the trials did show that Vitrase produced visual acuity in patients and a decreased hemorrhage density. Based on the negative news, ISTA’s stock dropped nearly 70 percent. (See BioWorld Today, March 27, 2002.)

In January, ISTA received fast-track status for Vitrase, allowing the company to submit its NDA in sections. Fast-track status is designated for products designed to treat patients with serious or life-threatening conditions and Anido suggested this may be the reason the FDA will allow the evaluation of Vitrase by its secondary endpoints.

“My assessment of it is that, first of all, there is no current therapy for vitreous hemorrhage, other than what they call watchful waiting or vitrectomy,” Anido said. “That’s why they gave us the fast-track designation, because there is no current therapy and because it is a life-altering disease.”

While the condition can be caused by injury, it is most commonly seen in diabetic retinopathy patients, Anido said.

The company said that based on market research it commissioned in 1999, about 450,000 cases of vitreous hemorrhage occur each year in the United States, and about half of these would be candidates for treatment with Vitrase.

ISTA also is studying Vitrase for patients with diabetic retinopathy, a leading cause of adult blindness, in a Phase IIa pilot study.