Frances Bishopp

After nine years of development of its topical antiviral drug, Lidakol, for oral herpes, Lidak Pharmaceuticals Inc. reported results of Phase III clinical trials of the product demonstrated statistically significant reduction of healing times of herpes episodes.

Based on the results, Lidak, of La Jolla, Calif., will file a new drug application (NDA) for marketing approval by the end of the year.

The data, established in a just-completed 743-patient multicenter, double-blind Phase III study, showed treatment with Lidakol met the statistical level of significance in terms of efficacy, therapeutic effect vs. placebo, to satisfy the required primary endpoint goal for submitting an NDA to the FDA, David Katz, president and CEO of Lidak, told BioWorld Today. Healing time is the primary endpoint efficacy parameter required by the FDA for approval of this drug.

Also, in secondary endpoints evaluated in the trials, treatment with Lidakol reduced, to a statistically significant degree vs. placebo, major herpes symptoms such as pain, itching, tingling and burning, which create the most clinically bothersome problems for patients suffering from this disease, Katz said.

In another secondary endpoint parameter, Lidakol treatment significantly increased the incidence of episode abortion, vs. placebo treatment, in one subset of the patient population participating in these studies, he said. This parameter of episode abortion is another clinically important benefit to patients suffering from oral herpes.

Imbued with anti-inflammatory properties, Lidakol (n-docosanol 10 percent cream) is a long-chained fatty alcohol that acts by interfering with viral entry into target cells.

For a virus to replicate it must enter the nucleus of the cell. Lidakol differs from currently approved marketed drugs in that it interferes with the viral entry into the target cell, said Lisa Dawn Katz, director of corporate communications and investor relations at Lidak.

"Currently approved methods to treat herpes interfere with the virus once it is already inside the target cell's nucleus," Katz said.

In 1996, Lidak reported Lidakol failed to achieve statistical significance in two Phase III studies because the placebo performed better than expected. The placebo contained all the substances of Lidakol except n-docosanol, which was replaced by another chemical compound. Lidak did not disclose the compound, saying while the company doesn't plan to evaluate it in terms of a potential drug, it may seek patent protection and study it further.

The companythen asked for FDA permission to use a placebo control of its choosing for an additional Phase III study, which was granted and a new set of Phase III trials planned.

Lidak has licensed marketing and distribution rights to Lidakol in many parts of the world, including all of Europe and certain African and Mid-East countries, to Yamanouchi Europe, of the Netherlands; Japan to Tokyo-based Grelan Pharmaceutical Co. Ltd.; Israel to CTS Chemical Industries, of Kiryat Malachi; Korea to Boryung Pharma Co. Ltd., of Seoul; and the North American continent to Bristol-Myers Squibb Co., of New York.

Lidak also has completed, with positive results, a topical Phase I/II pilot study using Lidakol on Kaposi's sarcoma skin lesions.

In June 1997, Lidak completed Phase I/II clinical trials of its Large Multivalent Immunogen (LMI) vaccine, LP2307, in stage three and four malignant melanoma patients in which the treatment proved safe and well tolerated. The LMI technology is designed to stimulate tumor-specific killer cells, known as cytotoxic T lymphocytes, to combat invading tumor cells in the cancer-bearing host.

Lidak, as of June 30, 1997, had $15.8 million in cash. The company's burn rate is approximately $400,000 per month, Katz said.

Lidak's stock (NASDAQ:LDAKA) closed Friday at $3.063, up $0.563. *