Interleukin-23 inhibition for psoriasis shows ‘wow’ factor

GENEVA – The merits of addressing interleukin-23 as a novel therapeutic target in moderate to severe plaque psoriasis were abundantly displayed in 2-year outcomes data for two anti–IL-23 monoclonal antibodies – guselkumab and tildrakizumab – in studies presented back to back at the annual congress of the European Academy of Dermatology and Venereology.

These long-term, open-label extensions of previously reported phase 3, randomized, double-blind clinical trials provided evidence of multiple advantages for IL-23 inhibition. The story was similar for both agents: After 2 years of use in the extension studies, the two biologics demonstrated stellar treatment response rates that would have been unimaginable only a few years ago, maintenance of efficacy without drop-off over time, exceedingly low dropout rates, and a safety picture that remains reassuring as experience accumulates. Also, the subcutaneously administered IL-23 inhibitors are attractive from a patient convenience standpoint in that maintenance guselkumab is dosed at 100 mg once every 8 weeks, and tildrakizumab is given once every 12 weeks.

Still, there are differences between the two drugs, most notably in apparent effectiveness. While more than half of guselkumab-treated patients had a Psoriasis Area Severity Index (PASI) 100 response – that is, totally clear skin – at 2 years, that was the case for only one-quarter to one-third of patients on tildrakizumab.

Guselkumab (Tremfya) was approved by the Food and Drug Administration in July 2017 for treatment of adults with moderate to severe plaque psoriasis. Tildrakizumab remains investigational.

Guselkumab

The 2-year, open-label extension of the phase 3 VOYAGE 1 trial included 735 patients who were either on guselkumab continuously, crossed from adalimumab (Humira) to guselkumab after 48 weeks, or switched from placebo after 16 weeks.

^{Bruce Jancin/Frontline Medical News}

Dr. Andrew Blauvelt

PASI 100 rates at 2 years were 49%-55% in the three patient groups. Of the patients in these groups, 54%-59% achieved an Investigator’s Global Assessment (IGA) score of 0. IGA scores of 0 or 1, meaning clear or almost clear skin, were present in 82%-85% of patients at 2 years.

“Dropout rate is an important consideration in long-term studies,” observed Dr. Blauvelt, a dermatologist and president of Oregon Medical Research Center in Portland. “For patients on continuous guselkumab there was a 6% dropout rate in the first year and 6% in the second year, so 88% of patients that started guselkumab were still on guselkumab 2 years later. That’s impressive. In the other two groups, the dropout rate was 2% per year.”

A Dermatology Life Quality Index (DLQI) score of 0 or 1, meaning no disease effects on quality of life, was recorded in 62.5% of the continuous guselkumab group at 48 weeks and 71.1% at 2 years.

“The interesting thing here is that, even though the efficacy numbers are fairly constant between year 1 and year 2, the DLQI goes up and up. Surprising? Maybe not. I think it shows patients are getting happier and happier over time with their disease control,” Dr. Blauvelt continued.

Rates of serious adverse events remained low and stable, with no negative surprises during year 2. The serious infection rate was 1.02 cases/100 patient-years in year 1 and 0.84 cases/100 patient-years in year 2. No cases of tuberculosis, opportunistic infections, or serious hypersensitivity reactions occurred during 2 years of treatment.

Tildrakizumab

Two-year results from the ongoing 5-year extension of the phase 3 reSURFACE 1 and reSURFACE 2 trials were presented by Kim A. Papp, MD, PhD, president of Probity Medical Research, Waterloo, Ont. This presentation of 2-year outcomes for 1,237 study participants was a feat, considering that the 12-week results of the trials had been published less than 3 months earlier (Lancet. 2017 Jul 15;390[10091]:276-88).

^{Bruce Jancin/Frontline Medical News}

Dr. Kim A. Papp

“I think these data are very compelling that the loss of response over time is minimal,” according to the dermatologist. “We’ve also seen that safety over 2 years has no surprises; in fact, it’s remarkably quiet. The rate of severe infections, which is important to look at for any treatment suppressing the immune system, is low and occurs almost independent of dose, which is very hopeful. It’s a promising sign.”

Indeed, the serious infection rate was 0.8 cases/100 patient-years regardless of whether subjects were on tildrakizumab at 100 mg or 200 mg.