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Sebum Control Nanoparticles and Light Nitric oxide has been studied in wound healing, cancer treatment and cardiovascular disease. And it may soon become a valuable treatment tool for dermatologists. Novan Therapeutics (novantherapeutics.com), a company developed to pursue a variety of stabilized NO-based medical therapies, is currently conducting Phase 2 clinical trials of SB204, an NO-based topical for sebum reduction. The company recently released a white paper, "Topical Nitric Oxide as a First-in-Class, Local Antiandrogen Therapy for the Treatment of Acne and Male Pattern Baldness," by William Kelce, PhD. "It shows multiple ways that NO could either shut down androgen synthesis in the skin or inhibit the conversion of testosterone to its active metabolites in the skin," says Nathan Stasko, PhD, a chemist and co-founder of Novan. The Innovation Factory—an entrepreneurial incubator that specializes in medical devices and life sciences—has developed Sebacia, a silica and gold-based nanoparticle applied in a topical cream that causes photothermal damage to the sebaceous glands when activated by wavelengths commonly used in laser hair removal devices. The company partnered with Rox Anderson at Massachusetts General Hospital as a thought leader on the use of lasers in dermatology, and Rice University which has a nanotechnology based on a physics theory from the 1800s called the Mai Theory "where you can basically engineer particles to preferentially absorb certain wavelengths of light," says Todd Meyer, COO of Sebacia. The microparticles include a silica sphere covered in a gold metallic shell. "It's the ratio of diameter between the inner and outer shell that allows you to tune the particle to a specific wavelength," he says. They are delivered trans-follicularly into the sebaceous glands and then irradiated with laser to selectively heat the gland. The particle was designed to work with the 800nm wavelength, but is also effective with other common laser hair removal wavelengths, including 755nm and 1064nm. "You design the particle to peak absorb specific wavelengths, so there's a little bit of efficiency loss when you move off that peak," says Meyer. The company has been conducting pilot studies outside of the United States and has treated more than 100 patients, primarily in facial acne. Their most recent study was a 48-patient, randomized, active control, crossover study comparing the Sebacia treatment and a 2% salicylic wash. Results were measured by lesion count. "At 12 weeks, we're looking at a mean reduction in inflammatory lesions of 35% in the treatment arm and 16% in the salicylic arm," says Meyer. "At 28 weeks, our mean in the treated population is -61%. The continued improvement at 28 weeks is consistent with the proposed mechanism of action in terms of the photothermal modification of the gland." In pre-clinical testing that mimicked clinical usage with multiple exposures, the company reports a return to baseline levels of gold within a month of treatment. "So basically zero gold," says Meyer. "As far as we can tell, we think we're probably just expressing the gold particle back out through the follicle." He notes that there is no limitation on sun exposure following treatment and patients' self-reported pain scores during treatment were "about a three on a zero to 10 pain scale, so this is really a procedure that patients can walk out of the office and resume normal daily life," he says. Company-sponsored in vitro research conducted by Diane Thiboutot, MD, professor of dermatology at Penn State Hershey College of Medicine, showed that immortalized human sebocytes treated with SB204 showed reduced sebum production. Additional research using the golden Syrian hamster flank organ model, showed that SB204 inhibited the growth of the hamster flank organ by more than 50% compared to vehicle control, further suggesting anti-androgenic activity. "The important thing is that it's local," says Stasko. "The nitric oxide interacts with the surface of the skin, and your body never really sees any of the systemic effects. It only acts right there at the skin and it is transient." The difficulty in developing NO-based therapies has been traditionally related to formulation. "The biggest challenge is how do I get a sustained release of a gas on the skin—that's really the question, and our platform enables us to do this," says Stasko. 8 July/August 2013 | ACNE & ROSACEA Photo courtesy of James Tunnell, PhD, University of Texas, Austin Topical Nitric Oxide