A new trial has found that adding sildenafil (Viagra) to pirfenidone (Esbriet) did not offer a treatment benefit in patients with advanced idiopathic pulmonary fibrosis (IPF) and risk of pulmonary arterial hypertension (PAH).
The combination of sildenafil and pirfenidone was found infective versus pirfenidone plus placebo up to 52 weeks in patients with IPF.
The study findings were published online Tuesday in The Lancet.
Dr. Jürgen Behr, Dr. Steven Nathan, Dr. Wim A Wuyts, Dr. Nesrin Mogulkoc Bishop, Dr. Demosthenes Bouros, Dr. Katerina Antoniou, et al. were among the researchers of the trial.
“We aimed to assess the efficacy and safety of sildenafil added to pirfenidone versus placebo added to pirfenidone for 52 weeks in patients with advanced IPF and at risk of group 3 pulmonary hypertension,” the authors wrote.
The researchers did a multicenter, double-blind, randomized, placebo-controlled, Phase IIB study at 56 university clinics and research hospitals in Canada, Europe, Israel, and Africa.
The patients enrolled had advanced IPF and were at risk of pulmonary hypertension. They were divided into two groups. One group received oral sildenafil 20 mg tablets and oral pirfenidone 801 mg capsules thrice a day. The other group received a placebo and oral pirfenidone capsules thrice a day.
The researchers assessed the safety and efficacy of the drugs in all patients who were screened from January 13, 2017, to August 30, 2018.
Of all the patients, 247 were screened for eligibility, while 177 were assessed for the primary outcome.
The authors found no difference in the proportion of patients with disease progression over 52 weeks between the sildenafil and placebo groups of 89 patients.
Instead, serious treatment-related side events were reported in 54 patients in the sildenafil group and 55 patients in the placebo group. The side effects led to mortality in 22 patients in the sildenafil group and 26 in the placebo group.
The author interpreted, “Addition of sildenafil to pirfenidone did not provide a treatment benefit versus pirfenidone plus placebo up to 52 weeks in patients with advanced IPF and risk of pulmonary hypertension.”
“No new safety signals were identified with either treatment,” they added. The researchers continued, “Although the absence of a beneficial treatment effect suggests that sildenafil is not an appropriate treatment in the overall population, further research is required to establish if specific subgroups of patients with IPF might benefit from sildenafil.”