NEW ORLEANS – according to results of a phase 2 clinical trial presented as a late-breaker at the annual meeting of the American Academy of Dermatology.
The phase 2b data, which are prompting a phase 3 trial, suggest that the drug, called orismilast, “is a potential new addition to the psoriasis armamentarium,” reported Lars E. French, MD, professor and chair, department of dermatology, Ludwig Maximilian University of Munich (Germany).
Ted Bowsworth/MDedge News
Dr. Lars E. French
At the same session, findings from another study supported off-label use of oral roflumilast (Daliresp and generic), a PDE4 inhibitor approved for severe chronic obstructive pulmonary disease (COPD). The only PDE4 inhibitors with an indication for psoriasis are roflumilast, approved as a cream (Zoryve), and apremilast (Otezla), approved as an oral therapy.
Phase 2 study of orismilast
In the orismilast trial, Dr. French attributed the efficacy observed to the potency of orismilast on the B and D subtypes of PDE4 associated with inflammation. One clue is that these specific subtypes are overly expressed in the skin of patients with either psoriasis or atopic dermatitis.
“When compared to apremilast, orismilast is at least two to fivefold more potent on all PDE4 isoforms and up to 39 times more potent on some of the PDE4 B and D isoforms,” said Dr. French, referring to preclinical findings in human whole blood and blood cells and in a mouse model of chronic inflammation.
The efficacy of orismilast in an immediate-release oral formulation was previously demonstrated in a recently published phase 2a trial, but the newest study tested a modified-release formulation of orismilast to test its potential to improve tolerability.
In the study, 202 adult patients with moderate to severe psoriasis (Psoriasis Area Severity Index [PASI] score ≥ 12) were randomly assigned to one of three doses of orismilast or to placebo. Each of the three doses – 20 mg, 30 mg, or 40 mg – were administered twice daily. The primary endpoint was change in PASI score at 16 weeks. Secondary endpoints included PASI 75 responses (signifying 75% clearance) and safety.
Relative to placebo, which was associated with a PASI improvement of 17%, all three of the tested orismilast doses were superior in a dose-dependent manner. The rates of response were 53%, 61%, and 64% for the 20-mg, 30-mg, and 40-mg twice-daily doses, respectively.
The PASI improvements were rapid, Dr. French said. At 4 weeks, PASI scores climbed from baseline by nearly 40% for those on all orismilast doses, which was more than double the improvement in the placebo group.
In the intention-to-treat analysis with missing data counted as nonresponders, the proportion of patients reaching PASI-75 scores at 16 weeks were 39%, 49%, 45%, and 17%, in the 20-mg, 30-mg, 40-mg, and placebo groups, respectively. The proportion of patients experiencing complete or near-complete skin clearance defined by a PASI 90 were 24%, 22%, 28%, and 8%, respectively.
The side-effect profile was consistent with other PDE4 inhibitors. The most common adverse events included gastrointestinal complaints, such as diarrhea and nausea, as well as headache and dizziness. But the majority of these events were of low grade, and they were largely confined to the first 4 weeks of treatment, which is a pattern reported with other PDE4 inhibitors in psoriasis and other chronic inflammatory diseases, such as COPD, according to Dr. French.
“There were no discontinuations for a treatment-related adverse event in the arms receiving either the 20-mg or the 30-mg doses,” Dr. French reported. There were only two serious adverse events, and neither were considered by trial investigators to be related to orismilast.
Based on the limited therapeutic gain but greater risk for adverse events on the 40-mg twice-daily dose, “the question is now whether to move forward with the 20-mg or the 30-mg dose,” said Dr. French, who said planning of a phase 3 trial is underway.