On the basis of global pharmacovigilance data collected over 4 years, the safety profile of nintedanib in patients with IPF was consistent with that observed in clinical trials, with no new safety concerns observed. The most frequent adverse event reported in the global pharmacovigilance database was non-serious diarrhea, in line with observations from clinical trials [5, 11,12,13,14], observational studies conducted in clinical practice [15,16,17,18,19,20,21,22,23], and post-marketing surveillance data collected in the USA in the year following the approval of nintedanib as a treatment for IPF [24].
Nintedanib is an intracellular inhibitor of tyrosine kinases that inhibits processes fundamental to the pathogenesis of pulmonary fibrosis [9, 10, 25, 26]. Diarrhea is a known adverse event associated with tyrosine kinase inhibitors. The precise mechanism behind this is unknown, but it may be that inhibition of the vascular endothelial growth factor receptor (VEGFR) causes morphometric changes in the bowel mucosa, altering motility [27]. In the INPULSIS trials, 62.4% of nintedanib-treated patients had at least one adverse event of diarrhea over 52 weeks, with its onset occurring within 3 months in most of these patients [11]. Investigators were provided with guidelines for the management of diarrhea through symptomatic therapy and dose adjustment (dose reduction to 100 mg twice daily and/or treatment interruption) [11]. Diarrhea led to treatment discontinuation in 4.4% of patients over 52 weeks [11].
Elevations in liver enzymes and bilirubin (including drug-induced liver injury) may occur in patients treated with nintedanib and it is recommended that liver function tests (ALT, AST, bilirubin) be conducted prior to the initiation of treatment, at regular intervals during the first 3 months of treatment, and periodically thereafter or as clinically indicated [28]. It is recommended that nintedanib therapy be interrupted or the dose reduced in patients with ALT or AST > 3 but < 5 × ULN without signs of liver damage [28]. Nintedanib should be discontinued in patients with ALT or AST > 3 × ULN with signs or symptoms of liver injury, or with ALT or AST > 5 × ULN [28]. In the majority of cases, liver enzyme and bilirubin elevations in patients treated with nintedanib were reversible with treatment interruption or dose reduction [28].
As an inhibitor of VEGFR, nintedanib is associated with an increased risk of bleeding. It is recommended that patients treated with nintedanib who are on full-dose anticoagulation therapy be monitored so that anticoagulation treatment can be adjusted as necessary [28]. Consistent with findings from the INPULSIS trials [11], most of the bleeding events in the pharmacovigilance database were non-serious and the most common type of bleeding event was epistaxis. Clinical trial data, including those collected in INPULSIS-ON over a treatment duration of up to 68 months, suggest that the risk of bleeding does not increase with prolonged nintedanib treatment [6, 14]. However, patients with increased risk of bleeding (i.e., requiring fibrinolysis, full-dose therapeutic anticoagulation, or high-dose antiplatelet therapy) were excluded from clinical trials of nintedanib. Just over a quarter of patients who had a bleeding event reported in the pharmacovigilance database were receiving medications that alter hemostasis, i.e., antithrombotic agents. Although the dose of these medications was not reported and, as such, use of full-dose therapeutic anticoagulation or high-dose antiplatelet therapy could not be assessed, the types of bleeding event were generally consistent between patients who were and were not receiving these medications. However, serious bleeding events were more common than non-serious bleeding events in patients receiving medications altering hemostasis, whereas non-serious bleeding events were more common than serious events in patients not receiving such medication.
Cardiovascular disorders are common comorbidities in patients with IPF [29]. In the INPULSIS trials, a higher proportion of patients in the nintedanib group than in the placebo group had myocardial infarction (2.7% versus 1.2%), while a lower proportion had other ischemic heart disease (1.7% versus 3.1%) [11]. The incidence rates of MACE and myocardial infarction in the global pharmacovigilance database were lower than those observed in pooled data from the TOMORROW and INPULSIS trials [30]. The incidence rate of myocardial infarction in the database was lower than that observed in an analysis of US healthcare claims data from patients with IPF not treated with nintedanib [31]. Exposure-adjusted event rates of MACE and myocardial infarction in nintedanib-treated patients in INPULSIS-ON (after a median of 32 months of treatment) were similar to those observed in placebo-treated patients in the INPULSIS trials [6]. Overall, these data are reassuring with regards to the cardiovascular safety of nintedanib in patients with IPF.
A small number of patients in the INPULSIS trials and global pharmacovigilance database had gastrointestinal perforation. On the basis of the mechanism of action of nintedanib, caution should be used when treating patients who have had recent abdominal surgery, have a history of diverticular disease, or are receiving corticosteroids or non-steroidal anti-inflammatory drugs. A recent analysis of real-world data suggested that there may be a relationship between nintedanib and ischemic colitis (based on analysis of 10 cases) [32]. A signal assessment for ischemic colitis conducted using the global pharmacovigilance database in early 2020 identified 18 cases following 102,711 patient-years of exposure, a rate consistent with the background rate that would be expected in a population of similar age.
Clinical trial data suggest that nintedanib has a similar safety and tolerability profile across patient subgroups based on age, race, degree of lung function impairment, and use of statins and anti-acid medications [6, 12, 33,34,35]. However, serious adverse events appear to occur more frequently in patients with IPF who have more advanced gas exchange impairment (DLco < 35% predicted) [36]. In addition, observational studies conducted in clinical practice suggest that patients with more advanced disease are more likely to discontinue nintedanib because of adverse events [20, 21, 37]. Proactive counselling regarding possible adverse events and appropriate management through dose adjustment and symptom relief are crucial to optimize adherence and to improve outcomes [38, 39]. Importantly, the dose adjustments used to manage adverse events associated with nintedanib have been shown not to reduce the efficacy of nintedanib in reducing FVC decline [6, 40].
Strengths of our analyses of the global pharmacovigilance database include the cumulative exposure to nintedanib (over 60,000 patient-years compared with 548 patient-years in the INPULSIS trials) and the collection of data from an all-comers population of patients with IPF treated in clinical practice worldwide. Our analyses also have a number of limitations, including the likely under-reporting of non-serious adverse events, the reliance on the data that were reported without the opportunity to verify them, the lack of detailed information captured on adverse events and their impact, the absence of information on nintedanib dose adjustments or discontinuations, and the limited data available on the characteristics of patients who reported adverse events, including on concomitant medication use.