InSite Vision Inc. is clearly focused on a pivotal clinical trial of its compound ISV-401 to treat bacterial conjunctivitis.

The Alameda, Calif.-based ophthalmic products company said that following a meeting with the FDA, it has finalized its protocol and is moving ahead with plans to begin Phase III testing in the second quarter.

ISV-401 combines a formulation of azithromycin, a broad-spectrum antibiotic not currently used in ophthalmology, with DuraSite, InSite's drug-delivery vehicle designed for prolonged release. The controlled study is based on the same formulation and dosing regimen used in a Phase II study. The protocol also allows inclusion of both pediatric and adult patients in a single trial rather than requiring separate trials for each set of patients.

"The endpoint for these studies - other than to ensure that there is good ocular health - is to examine bacterial eradication as well as clinical cure," InSite President and CEO S. Kumar Chandrasekaran told BioWorld Today. "One examines bacterial eradication as a function of time, and at the same time examines clinical cure, which is edema chemosis and things of that nature."

He said the studies together would recruit 500 to 700 patients in the U.S. and abroad.

Prior clinical testing has pointed to the product's effectiveness. In September, InSite reported positive safety and efficacy results from a Phase II study, indicating clinical resolution and bacterial eradication for both Gram-positive and Gram-negative strains of acute bacterial conjunctivitis.

The randomized, multisite study compared a 1.0 percent concentration of ISV-401 with a DuraSite vehicle to placebo. Data included results from more than 30 patients with confirmed acute bacterial conjunctivitis in at least one eye.

The study also pointed to the drug's ability to improve dosing schedules. Data demonstrated that six drops of ISV-401 administered over five consecutive days produced clinical results comparable to those usually seen with more than 35 drops administered over seven days of currently marketed drugs.

"We essentially exploit the attributes of the technology and the drug toward improving the spectrum of activity for bacterial conjunctivitis, for example, and at the same time make it user friendly by reducing the number of administrations necessary," Chandrasekaran said. "That expands the potential market opportunity to include the pediatric market, a segment for which administration becomes a key attribute."

In preparation for Phase III testing and other potential studies of ISV-401, InSite has signed a manufacturing agreement for the product that would be used in such trials. Chandrasekaran said sufficient supply should begin to accumulate later this month.

Further development of the drug could come in collaboration. InSite said it is negotiating with potential partners for ISV-401's clinical trial efforts as well as subsequent commercial endeavors. The discussions include the treatment of trachoma, an ocular infection caused by the bacteria chlamydia trachomatis, a leading cause of preventable blindness.

"I would expect, especially with the very positive reading from the FDA, the momentum of these discussions should increase even further," Chandrasekaran said.

Partnering is nothing new to InSite, which last month entered a manufacturing, distribution and promotion agreement for its OcuGene glaucoma genetic test with Catania, Sicily-based SIFI (Societa Industria Farmaceutica Italiana) SpA in Italy.

Another recent collaboration includes a licensing agreement entered in August with Rochester, N.Y.-based Bausch & Lomb Inc. for ISV-403, a different ocular infection program. ISV-403 combines a fourth-generation fluoroquinolone, licensed from Tokyo-based SSP Co. Ltd., with the DuraSite delivery technology.

InSite is responsible for ISV-403's clinical development through new drug application approval from the FDA, with Bausch & Lomb responsible for subsequent commercial manufacturing and marketing. After an initial preferred equity investment, Bausch & Lomb will make additional equity investments in InSite as milestones are achieved. The licensing agreement grants Bausch & Lomb exclusive rights to ISV-403 in all areas excluding Japan, and with shared selling rights in Asia.

InSite's glaucoma activities include genomic research, using TIGR and other genes, for its diagnosis, prognosis and disease management test, as well as ISV-205, a novel glaucoma therapeutic. InSite's delivery technology also is used in its retinal disease program.

InSite's stock (AMEX:ISV) gained 12 cents Thursday to close at 85 cents.