Sirion Therapeutics Announces Positive Phase III Results For Difluprednate

Sirion Therapeutics,
Inc., a privately held ophthalmic-focused biopharmaceutical company,
announced positive preliminary results from its Phase III difluprednate
(ST-601) program, which evaluated the steroid’s potential to rapidly
resolve inflammation in the eye following ocular surgery.

“We are very pleased with the data that demonstrate difluprednate’s
potential as a potent, well-tolerated steroid treatment for post-operative
inflammation,” said Dr. Roger Vogel, Sirion’s Chief Medical Officer. “Based
on these data, Sirion is moving forward with its plans to submit a New Drug
Application to the FDA.”

The Phase III program consisted of two multi-center, randomized,
double- masked studies that compared the safety and efficacy of
difluprednate 0.05% to placebo, dosed two (BID) or four (QID) times daily
beginning 24 hours after surgery. The studies included 439 subjects who
presented with Grade 2 (an inflammatory cell count greater than or equal to
10) or higher the day after surgery. Inflammation was measured by the
number of cells in the anterior chamber of the eye with a Grade 0 equaling
less than or equal to one cell. The primary efficacy endpoint measured the
proportion of subjects whose inflammation reached Grade 0 at Day 8.

Both difluprednate dosing regimens were superior to placebo at the
primary endpoint, reaching high statistical significance at Day 8 and
maintaining superiority through both the treatment period (Day 15) and the
tapering period (Day 29). At Day 15, 56% of subjects on the BID regimen
reached Grade 0 compared to 16% in the control group (p

The analysis demonstrated comparable clinical efficacy and acceptable
safety profiles for both BID and QID dosing of difluprednate.

“These are extremely robust data,” said Dr. Michael Korenfeld, an
ophthalmologist with Comprehensive Eye Care in Washington, Missouri who was
an investigator in the trial. “Being able to treat ocular inflammatory
disease with a more convenient dosing regimen and having the potential to
offer rapid resolution of inflammation after ocular surgery would represent
a meaningful advance for patients.”

“Sirion is very excited about these results. When we started this
program, we felt that difluprednate had the potential to be a major step
forward in the control of ocular inflammation. These results met our
highest expectations” said Barry Butler, President and CEO of Sirion. “We
look forward to bringing this important new treatment option to
ophthalmologists and patients.”

About Post-Operative Inflammation

There are more than 3.5 million ophthalmic surgeries performed each
year in the United States. Post-operative inflammation is a common
occurrence following these procedures. While it tends to be self-resolving,
some cases can lead to serious sequelae. If left untreated, inflammation
following ocular surgery can interfere with the patient’s visual
rehabilitation or lead to further complications, such as acute pain and
discomfort, chronic cystoid macular edema, posterior capsule fibrosis,
keratopathy, fibrin reaction, or chronic uveitis. As there is no way to
predict which patients might develop inflammatory complications, doctors
often prescribe steroids and/or NSAID drops. Most often, post-operative
inflammation lasts a relatively short time, though severe forms of
inflammation can persist for a longer period of time.

About Difluprednate (ST-601)

Difluprednate is a potent ophthalmic steroid emulsion that has the
potential to treat patients suffering from ocular inflammatory disease.
Difluprednate’s unique formulation permits rapid penetration of the cornea,
which promotes quick resolution of anterior chamber cells and flare. A
Phase 3 program evaluating difluprednate in patients with post-surgical
inflammation was completed in September of 2007, showing difluprednate’s
potential to rapidly eradicate ocular inflammation versus placebo while
maintaining an acceptable safety profile. In addition to post-surgical
inflammation, difluprednate is being evaluated in a Phase 3 program as a
treatment for patients with uveitis.

About Sirion Therapeutics, Inc.

Sirion Therapeutics is a privately held biopharmaceutical company
pursuing the discovery, development and commercialization of products
addressing unmet medical needs in the protection and preservation of
eyesight. Sirion’s pipeline includes four late-stage opportunities:
ganciclovir, a topical antiviral for herpetic keratitis with a planned NDA
submission in early 2008; difluprednate, a potent topical steroid in Phase
III development for post- operative inflammation and uveitis; cyclosporine,
a topical immunomodulator in Phase III testing for dry eye and fenretinide,
a first-in-class oral vitamin A binding protein antagonist in Phase II
development for geographic atrophy associated with dry AMD. In addition,
Sirion plans to leverage its expertise in ophthalmology and vision research
to identify additional candidates in back of the eye diseases, through both
internal research efforts and partnering opportunities. For more
information regarding Sirion, please visit Sirion’s website at

Sirion Therapeutics, Inc.