June 6 (UPI) -- Two Phase 3 clinical trials have shown that the drug, tildrakizumab, is effective and well-tolerated in patients with moderate-to-severe chronic plaque psoriasis.
Chronic plaque psoriasis affects more than 6 million Americans and up to a quarter of patients have more aggressive cases that affect between 10 and 100 percent of their skin surface.
"We have made a huge amount of progress in the treatment of moderate to severe psoriasis over the past 15 years," Dr. Alexa B. Kimball, president and CEO of Harvard Medical Faculty Physicians at Beth Israel Deaconess Medical Center and a professor of Dermatology at Harvard Medical School, said in a press release. "In these two trials, we tested whether this new, very targeted approach to a selected part of the inflammatory pathway would be effective in treating psoriasis, and it was -- dramatically so."
Tildrakizumab is an antibody that targets a very specific pathway and belongs to a class of treatments known as biologic agents or biologics, which are based on molecules that the body makes naturally repurposed to treat disease.
The Phase 3 clinical trials known as reSURFACE 1 and 2, funded by MERK, consisted of more than 1,800 patients at 250 sites all over the world.
Participants, who started the trial with 30 percent of their body covered with psoriasis, randomly received either 200 mg of tildrakizumab, 100 mg of tildrakizumab or an inactive placebo.
Over the 12-week study period, 65 percent of patients showed clear or almost clear skin, which was a 75 percent improvement measured by the Psoriasis Area Severity Index. Of the placebo group, fewer than 10 percent achieved the same level of improvement.
"The breakthrough here is that we have continued to refine our treatments to those that are likely to be most effective against psoriasis but less likely to affect other important pathways at the same time," Kimball said. "The study also suggests that the 12-week end point may be too early to see optimal efficacy. Patients may continue to improve and that's going to be important to show over time."
The first generation of biologics to hit the market about 15 years ago led to improved clinical outcomes in the treatment of psoriasis.
Tildrakizumab is being developed by Merck and Sun Pharma, which bought rights to the drug from Merck, and filed for FDA approval of it in late May. Results of the studies were published June 6 in The Lancet.