FDA ISSUES APPROVABLE LETTER FOR QLT PHOTOTHERAPEUTICS' PHOTOFRIN(R).

VANCOUVER, B.C.--(BUSINESS WIRE)--July 17, 1995--QLT PhotoTherapeutics Inc. (QLT) (NASDAQ: QLTIF, TSE: QLT) announced today that it has received from the United States Food and Drug Administration (FDA) an "approvable" letter for the Company's light-activated drug PHOTOFRIN(R) and associated devices.

The FDA notice specified that PHOTOFRIN(R) is approvable for use in Photodynamic Therapy (PDT) with OPTIGUIDE(TM) fiber optic diffuser, the Coherent Lambda Plus PDL1 and PDL2 Photodynamic lasers, the Laserscope Series 600 Dye modules and the Series 700 and 800 Laserscope Surgical Lasers, for palliation of patients with completely obstructing esophageal cancer, or of patients with partially obstructing esophageal cancer who, in the opinion of their physician, cannot be satisfactorily treated with Nd:Yag laser therapy.

Before approval may be granted by the FDA, QLT must submit some additional information relating to the chemistry and manufacturing of PHOTOFRIN(R) and make minor revisions to the labelling.

Dr. Randal D. Chase, QLT President and CEO, said the FDA's letter is a critical step toward final marketing approval for PHOTOFRIN and its associated light delivery devices.

"This is a big step toward the first ever marketing approval in the United States for a Photodynamic Therapy drug and we are delighted to be leading the way," Dr. Chase said. "We plan to provide the required information to the FDA in a timely fashion."

QLT submitted its application for approval in April of 1994. It included more than 200 volumes of data supporting QLT's New Drug Application for PHOTOFRIN(R) and three Pre-Marketing Applications for the associated PDT devices.

Clinical data submitted for review by the FDA included results from a multi-center randomized open-label trial comparing PDT with PHOTOFRIN(R) to thermal ablation therapy using Nd:Yag laser for the removal of tumor mass and subsequent local palliation. A total of 236 patients with partially obstructing esophageal carcinoma were enrolled in the study.

One month after treatment, 32 percent of the PDT-treated patients showed an objective tumor response, compared with only 20 percent of the patients treated with Nd:Yag thermal ablation therapy. Nine patients treated with PDT and two treated with ND:Yag had no visible evidence of tumor and were considered to have achieved complete tumor response.

In a second study contained in the submission, 19 patients with completely obstructing esophageal carcinoma not eligible for Nd: Yag laser therapy were treated with PDT with PHOTOFRIN(R). After one month, 42 percent of patients showed improvement in dysphagia, 32 percent of patients achieved partial objective tumor responses.

On September 12, 1994, the FDA's Oncology Drug Advisory committee voted 11 to 1 recommending that the FDA approve PHOTOFRIN(R) and associated light devices as a palliative treatment for completely obstructing cancers of the esophagus and for certain partially obstructing cancers of the esophagus.

QLT PhotoTherapeutics Inc. is a world leader in the development of new pharmaceutical products and applications for PDT, an emerging medical field that uses light-activated drugs in the treatment of cancer and other diseases. QLT's lead product, PHOTOFRIN(R), has been approved for the treatment of specific cancers in Canada, the Netherlands and Japan. QLT is the first company in any jurisdiction to gain regulatory approval for a light-activated drug for use in PDT. -0-

QLT Photo Therapeutics Inc. is listed on the NASDAQ National Market under the trading symbol "QLTIF" and on the Toronto Stock Exchange under the trading symbol "QLT". On May 16, 1995 Quadra Logic Technologies Inc. changed its name to QLT Photo Therapeutics Inc.

CONTACT: QLT PhotoTherapeutics Inc.

David J. Main, 604/871-1302 or 800/663-5486