Pfizer’s phase III OPT retreatment trial of tofacitinib meets primary efficacy endpoints

27th May 2014 (Last Updated May 27th, 2014 01:00)

US-based Pfizer has reported detailed results from the Oral treatment Psoriasis Trial (OPT) Retreatment study (A3921111), a Phase III trial evaluating tofacitinib, an oral Janus kinase (JAK) inhibitor, to treat adult patients with moderate-to-severe chronic plaque psoriasis.

US-based Pfizer has reported detailed results from the Oral treatment Psoriasis Trial (OPT) Retreatment study (A3921111), a Phase III trial evaluating tofacitinib, an oral Janus kinase (JAK) inhibitor, to treat adult patients with moderate-to-severe chronic plaque psoriasis.

The three-period trial showed that tofacitinib, as a 5mg or 10mg pill taken twice daily, met its two primary efficacy endpoints.

According to the company, the drug's safety profile of the drug in OPT Retreatment was consistent with previous studies and there were no new safety findings in the trial.

The trial's first primary endpoint assessed the maintenance of clinical response in patients who remained on tofacitinib after an initial treatment phase compared to patients who were switched to placebo (withdrawal phase).

"The OPT Retreatment data showed that patients who stayed on therapy with tofacitinib maintained their rates of response and for those who stopped therapy, a proportion of patients were able to regain their original clinical response when retreated with tofacitinib."

The second primary endpoint evaluated patients who lost half of their original clinical response during the withdrawal phase, and measured the proportion of these patients who regained their original clinical response after restarting treatment with tofacitinib.

Innovaderm Research lead investigator Robert Bissonnette said Psoriasis is a chronic disease that affects about 2%-3% of people worldwide, and there are times when patients with psoriasis may need to stop and restart therapy for medical or non-medical reasons, such as elective surgery or receipt of live immunisations.

"The OPT Retreatment data showed that patients who stayed on therapy with tofacitinib maintained their rates of response and for those who stopped therapy, a proportion of patients were able to regain their original clinical response when retreated with tofacitinib," Bissonnette said.

Tofacitinib is part of a new class of medicines being developed for the treatment of moderate-to-severe plaque psoriasis.

The Phase III randomised, double-blind, three-period, parallel group, placebo-controlled 56-week trial evaluated the efficacy and safety of the withdrawal and retreatment with tofacitinib compared to placebo in 674 adult patients with moderate-to-severe chronic plaque psoriasis.

In the initial 24 weeks of the trial, which was the secondary endpoint, patients were treated with either tofacitinib at a dose of 5mg or 10mg twice daily in a blinded manner.

During this period, 44% and 68% of patients who received tofacitinib 5mg and 10mg twice daily achieved at least a 75% reduction in the Psoriasis Area and Severity Index (PASI75), respectively, and 42% and 63% of patients who received tofacitinib 5mg and 10mg twice daily achieved a PGA response of clear or almost clear skin, respectively.

The company said that in the retreatment period, all patients resumed their original tofacitinib dose until week 56.