Promedior‘s investigational therapy for idiopathic pulmonary fibrosis (IPF) — PRM-151 — continues to benefit patients after 76 weeks of treatment, slowing the decline in lung function and exercise capacity, while maintaining a similar safety profile as previous studies of PRM-151, an extension study shows.
The results were presented at the American Thoracic Society 2019 International Conference that took place May 17–22 in Dallas, in a presentation titled “Long-Term Safety and Efficacy of Recombinant Human Pentraxin-2 in Patients with Idiopathic Pulmonary Fibrosis.”
A detailed description of the data was also published in the journal The Lancet Respiratory Medicine in an article, “Long-term treatment with recombinant human pentraxin 2 protein in patients with idiopathic pulmonary fibrosis: an open-label extension study.”
PRM-151 is a recombinant (lab-made) version of pentraxin-2, a protein able to direct some components of the immune system to naturally turn off and reverse fibrosis; it can also help remove and possibly heal scarred tissue. The compound was granted breakthrough therapy designation by the U.S. Food and Drug Administration in March this year.
In a previous double-blind, multicenter Phase 2 clinical trial (NCT02550873) in the U.S. and Europe, PRM-151 demonstrated promising effects in 117 IPF patients, when compared with a placebo. In that trial, patients assigned to PRM-151 received intravenous injections at a dose of 10 mg/kg on days one, three, and five in the first week of each cycle, followed by one infusion every month, for 28 weeks. At the end of treatment, the patients who received PRM-151 had slower lung function decline, as measured by forced vital capacity (FVC) — treated patients had an average decrease of 2.5%, whereas those who received the placebo had a decrease of 4.8%.
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Additionally, patients treated with PRM-151 also had a greater exercise capacity, as measured by the six-minute walk test. Patients given PRM-151 had an average decrease of a half-meter in distance walked, while those on the placebo averaged a decrease of 31.8 meters.
All patients who completed the 28 weeks of the study could choose to enter an open-label extension study, where they continued or switched to treatment with PRM-151.
The primary objective of the extension study was to assess PRM-151’s long-term safety and tolerability, as well as collect preliminary data on its long-term efficacy. This study included 111 participants on treatment for a total of up to 76 weeks. Of these participants, 37 had been in the placebo group in the previous trial, and 74 continued to receive PRM-151. Twenty eight of these patients (25%) discontinued treatment, mostly due to adverse events or for personal reasons.
Consistent with the results from the 28-week Phase 2 study, patients who stayed on treatment continued to have slower rates of decline in lung function and exercise capacity over 76 weeks.
In line with these results, those who switched from a placebo to PRM-151 also experienced a delay in both FVC decline and walking distance worsening. Their rate of FVC changed from an annual reduction of 8.7% to 0.9%, and the decline in distance walked dropped from a 54.9-meter reduction to a 3.5-meter reduction per year.
“Long-term treatment with PRM-151 was well tolerated, and the effects on percentage of predicted FVC and 6-min walking distance were persistent on continuation and positive in patients who crossed over from placebo. These findings support further study of PRM-151 in larger populations of patients with IPF,” the researchers wrote.
Regarding safety, the adverse events reported were in line with those seen previously for PRM-151 and with those known for IPF. Thirty-one patients (28%) experienced serious adverse events, of which five events were related to PRM-151 treatment. Eight patients died during the study, in most of the cases due to IPF and pneumonia.
“We are excited to present these positive long-term data for PRM-151 in IPF, a serious, life-limiting lung disease for which despite existing therapies, patient prognosis remains poor with a median survival of 3–5 years,” Jason Lettmann, CEO of Promedior, said in a press release.
“These data continue to support the disease-modifying potential of PRM-151 in combating IPF and, ultimately, in the treatment of additional fibrotic diseases. We look forward to advancing into our pivotal program for PRM-151 in early 2020,” Lettmann concluded.