Weighing the Benefit of a Novel Coal Tar in Combination with UV Light

Clinicians typically employ a number of treatment modalities for psoriasis. This sometimes leads to experimenting with various combination therapies, which can maximize the benefit of different approaches. In a recent publication, Jerry Bagel, MD, Clinical Assistant Professor of Dermatology at Columbia University College of Physicians and Surgeons, examined the effects of a unique combination of coal tar and Narrowband- UVB phototherapy.1 Specifically, the study evaluated the safety, efficacy, and convenience of a novel LCD coal tar (liquor carbonis distillate, Psorent, NeoStrata) and NB-UVB. Ahead, Dr. Bagel discusses the results and the importance of combination approaches to psoriasis.

What was the impetus for this study?

While phototherapy remains a mainstay in psoriasis treatment, it's also known for its inconvenience. Patients typically require several treatments per week, which is a challenge if for no other reason than the demanding schedule it requires patients to keep. Dr. Bagel notes that another psoriasis treatment also marked by impracticality, albeit for different reasons, is coal tar. According to Dr. Bagel, coal tars are effective and easy to apply, but they have drifted to the background of psoriasis treatments because they have the potential to intrude on a patient's life. “Coal tars have always been associated with problems like leaving stains or giving off a foul stench,” he says. “While their clinical benefit is notable, unpleasant side effects such as these likely steered many potential users away,” notes Dr. Bagel.

Given that both of these therapies are known for their efficacy, Dr. Bagel observes that the downside of each may be diminished when they are used in combination. Moreover, he says, it may reduce the time to overall improvement of psoriasis.

What distinguishes this novel LCD from previous coal tars?

Dr. Bagel notes that tar treatments have been used successfully in various forms of plaque psoriasis over the years. But due to characteristics of the tar (i.e. odor, texture, etc.), patients have not been receptive to treatment, especially when they are responsible for applying it. “Tar treatments can be used effectively in hospital and outpatient settings, when treatment is prepared and administered by health professionals, but they simply are not cosmetically acceptable for home use,” he says. NeoStrata's novel coal tar Psorent was designed with the goal of reducing these elements. It is scent-free and stain-free, which made it an ideal candidate for this study, according to Dr. Bagel.

What do the results of the study suggest about the potential of coal tars and NB-UVB treatments?

Patients applied LCD to half of their bodies twice daily at home and were given NB-UVB therapy to the entire body three times a week for up to 12 weeks. Dr. Bagel notes that the response was much more significant on the side of the body treated with coal tar and phototherapy. “We found that patients responded significantly and in much shorter durations than would be expected of either treatment individually,” Dr. Bagel notes.

The median time to clearance or minimal disease was reduced by three weeks in at least 50 percent of the population, with statistically significant response observed the end of week four. Severity of psoriasis did not appear to have any impact on treatment, as all patients in the study had moderate to severe disease.

Importantly, observes Dr. Bagel, these findings may suggest that with the right combination, fewer light treatments are needed to reach the desired outcomes. “While both NB-UVB and coal tars are effective individually, the combination of them appears to increase efficacy within shorter spans of time,” says Dr. Bagel.

More Study Needed
While these results are encouraging, Dr. Bagel notes that a larger study might reveal more about the efficacy and safety of this combination therapy. “These results point to the great potential of Psorent in combination with UVB therapy, but more inquiries into it may help to determine more details regarding the optimal amount of light with tar vs. without tar, and erythemogenic vs. suberythemogenic doses of NB-UVB,” Dr. Bagel explains. Nevertheless, these results suggest that incorporating an at home regimen with a novel LCD such as Psorent into phototherapy represents a safe, convenient approach to improving psoriasis more quickly.

Bagel, J. LCD plus NB-UVB reduced time to improvement of psoriasis vs. NB-UVB alone. J Drug Dermatol. 2009 Apr; 8(4): 351-7.