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TKI preserved lung function in patients with fibrosing interstitial disease



In patients with fibrosing lung diseases other than idiopathic pulmonary fibrosis (IPF), nintedanib, a tyrosine kinase inhibitor, substantially reduced the rate of decline in lung function, according to findings from a phase 3, placebo-controlled trial presented at the annual congress of the European Respiratory Society.

Dr. Kevin R. Flaherty Ted Bosworth/MDedge News

Dr. Kevin R. Flaherty

The trial, called INBUILD, enrolled patients who had a progressive lung disease with a fibrosing phenotype, such as interstitial pneumonia with autoimmune features (IPAF) or noninterstitial pneumonia (NSIP), on the premise that these conditions might share a pathology responsive to a common therapy, explained Kevin R. Flaherty, MD, of National Jewish Health, Denver. The INBUILD trial was a randomized, double-blind, placebo-controlled, parallel-group trial conducted at 153 sites in 15 countries. A total of 663 patients underwent randomization and received at least one dose of nintedanib (332) or placebo (331).

Patients with fibrosing lung disease affecting more than 10% of lung volume were randomized to 150 mg twice daily of nintedanib, which inhibits intracellular growth factors implicated in fibrosis and is already indicated for IPF, or matching placebo.

On the primary endpoint of change in forced vital capacity (FVC) at 52 weeks, those in the nintedanib arm lost lung function at a rate that was less than half that of those randomized to placebo (–80.8 vs. –187.8 mL/year; P less than .001).

In a preplanned stratification, the protection from nintedanib against a decline in lung function was found to be at least as good in those with a usual interstitial pneumonia (UIP-like) pattern of fibrosis on baseline imaging (–82.9 vs. –211.1 mL/year), compared with those with other fibrotic patterns (–79.0 vs. –154.2 mL/year). The UIP-like subgroup represented about 60% of those enrolled.

“The relative protection from decline in lung function supports the hypothesis that progressive fibrosing interstitial lung diseases have a similar pathobiologic mechanism,” said Dr. Flaherty. Results from the INBUILD were published simultaneously with his ERS presentation (N Engl J Med. 2019 Sep 29. doi: 10.1056/NEJMoa1908681).

The curves documenting change of lung function in favor of nintedanib relative to placebo separated within 12 weeks of treatment initiation, according to Dr. Flaherty. The ERS-invited discussant, Martin Kolb, MD, PhD, professor of respirology, McMaster University, Hamilton, Ont., called the reductions in loss of lung function “profound” and “very impactful.”

However, despite these reductions, there was no significant difference in quality of life as measured with the King’s Brief Interstitial Lung Disease (KBILD) questionnaire, which was a secondary outcome. The problem was that there was little change in KBILD in either group at 52 weeks, limiting the ability to show differences.

The rates of death were numerically lower at 52 weeks in the nintedanib arm for the study overall (4.8% vs. 5.1%) and for the UIP-like subgroup (5.3% vs. 7.8%), but the differences did not reach statistical significance.

A suggestion of benefit was derived from a design feature of INBUILD that called for patients to remain on blinded therapy until all enrolled patients completed the trial. When the effect of nintedanib was evaluated in this extended analysis, the event curves for the combined endpoint of interstitial lung disease or death separated and approached significance.

In this extended analysis, which suggests that clinical benefit is likely to accrue after longer periods of treatment, “we saw similar trends when we looked at mortality as an independent outcome,” Dr. Flaherty reported.

More patients in the nintedanib group discontinued therapy because of adverse events (19.6% vs. 10.3%), but Dr. Flaherty characterized the rate of serious adverse events as “similar.” He made this statement even though several adverse events, particularly those involving the gastrointestinal tract, such as diarrhea (66.9% vs. 23.9%), nausea (28.9% vs. 9.4%), vomiting (18.4% vs. 5.1%), and abdominal pain (10.2% vs. 2.4%), were higher in the nintedanib arm.

The INBUILD trial demonstrates that nintedanib preserves lung function in fibrosing lung diseases other than IPF. In his review of this paper, Dr. Kolb pointed out that non-IPF etiologies represent about 75% of interstitial lung diseases. For these patients “we have no drugs, so there is a big medical need.”

Dr. Flaherty reports no potential conflicts of interest. The study was funded by Boehringer-Ingelheim, which produces nintedanib.

SOURCE: Flaherty KR et al. N Engl J Med. 2019 Sep 29. doi: 10.1056/NEJMoa1908681.

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