Pharmacotherapeutic group: Drugs for obstructive airway diseases, other systemic drugs for obstructive airway diseases, ATC code: R03DX07
Mechanism of action
Roflumilast is a PDE4 inhibitor, a non-steroid, anti-inflammatory active substance designed to target both the systemic and pulmonary inflammation associated with COPD. The mechanism of action is the inhibition of PDE4, a major cyclic adenosine monophosphate (cAMP)-metabolizing enzyme found in structural and inflammatory cells important to the pathogenesis of COPD. Roflumilast targets the PDE4A, 4B and 4D splicing variants with similar potency in the nanomolar range. The affinity to the PDE4C splicing variants is 5 to 10-fold lower. This mechanism of action and the selectivity also apply to roflumilast N-oxide, which is the major active metabolite of roflumilast.
Pharmacodynamic effects
Inhibition of PDE4 leads to elevated intracellular cAMP levels and mitigates COPD-related malfunctions of leukocytes, airway and pulmonary vascular smooth muscle cells, endothelial and airway epithelial cells and fibroblasts in experimental models. Upon in vitro stimulation of human neutrophils, monocytes, macrophages or lymphocytes, roflumilast and roflumilast N-oxide suppress the release of inflammatory mediators e.g. leukotriene B4, reactive oxygen species, tumour necrosis factor α, interferon γ and granzyme B.
In patients with COPD, roflumilast reduced sputum neutrophils. Furthermore, roflumilast attenuated influx of neutrophils and eosinophils into the airways of endotoxin challenged healthy volunteers.
Clinical efficacy and safety
In two confirmative replicate one-year studies (M2-124 and M2-125) and two supplementary six-month studies (M2-127 and M2-128), a total number of 4,768 patients were randomised and treated, of whom 2,374 were treated with roflumilast. The design of the studies was parallel-group, double-blind and placebo-controlled.
The one-year studies included patients with a history of severe to very severe COPD [FEV1 (forced expiratory volume in one second) ≤50% of predicted] associated with chronic bronchitis, with at least one documented exacerbation in the previous year and with symptoms at baseline as determined by cough and sputum score. Long-acting beta-agonists (LABAs) were allowed in the studies and were used in approximately 50% of the study population. Short-acting anticholinergics (SAMAs) were allowed for those patients not taking LABAs. Rescue medicinal products (salbutamol or albuterol) were allowed on an as-needed basis. The use of inhaled corticosteroids and theophylline was prohibited during the studies. Patients with no history of exacerbations were excluded.
In a pooled analysis of the one-year studies M2-124 and M2-125, roflumilast 500 micrograms once daily significantly improved lung function compared to placebo, on average by 48 ml (pre-bronchodilator FEV1, primary endpoint, p<0.0001), and by 55 ml (post-bronchodilator FEV1, p<0.0001). The improvement in lung function was apparent at the first visit after 4 weeks and was maintained up to one year (end of treatment period). The rate (per patient per year) of moderate exacerbations (requiring intervention with systemic glucocorticosteroids) or severe exacerbations (resulting in hospitalisation and/or leading to death) after 1 year was 1.142 with roflumilast and 1.374 with placebo corresponding to a relative risk reduction of 16.9% (95% CI: 8.2% to 24.8%) (primary endpoint, p=0.0003). Effects were similar, independent of previous treatment with inhaled corticosteroids or underlying treatment with LABAs. In the subgroup of patients with history of frequent exacerbations (at least 2 exacerbations during the last year), the rate of exacerbations was 1.526 with roflumilast and 1.941 with placebo corresponding to a relative risk reduction of 21.3% (95% CI: 7.5% to 33.1%). Roflumilast did not significantly reduce the rate of exacerbations compared with placebo in the subgroup of patients with moderate COPD.
The reduction of moderate or severe exacerbations with roflumilast and LABA compared to placebo and LABA was on average 21% (p=0.0011). The respective reduction in exacerbations seen in patients without concomitant LABAs was on average 15% (p=0.0387). The numbers of patients who died due to any reason were equal for those treated with placebo or roflumilast (42 deaths each group; 2.7% each group; pooled analysis).
A total of 2,690 patients were included and randomised in two supportive 1-year studies (M2-111 and M2-112). In contrast to the two confirmative studies, a history of chronic bronchitis and of COPD exacerbations was not requested for patients' inclusion. Inhaled corticosteroids were used in 809 (61%) of the roflumilast treated patients, whereas the use of LABAs and theophylline was prohibited. Roflumilast 500 micrograms once daily significantly improved lung function compared to placebo, on average by 51 ml (pre-bronchodilator FEV1, p<0.0001), and by 53 ml (post-bronchodilator FEV1, p<0.0001). The rate of exacerbations (as defined in the protocols) were not significantly reduced by roflumilast in the individual studies (relative risk reduction: 13.5% in Study M2-111 and 6.6% in Study M2-112; p= not significant). Adverse events rates were independent of concomitant treatment with inhaled corticosteroids.
Two six-month supportive studies (M2-127 and M2-128) included patients with a history of COPD for at least 12 months prior to baseline. Both studies included moderate to severe patients with a non-reversible airway obstruction and a FEV1 of 40% to 70% of predicted. Roflumilast or placebo treatment was added to continuous treatment with a long-acting bronchodilator, in particular salmeterol in Study M2-127 or tiotropium in Study M2-128. In the two six-month studies, pre-bronchodilator FEV1 was significantly improved by 49 ml (primary endpoint, p<0.0001) beyond the bronchodilator effect of concomitant treatment with salmeterol in Study M2-127 and by 80 ml (primary endpoint, p<0.0001) incremental to concomitant treatment with tiotropium in Study M2-128.
Study RO-2455-404-RD was a one-year study in COPD patients with a baseline (pre-bronchodilator) FEV1 <50% of predicted normal and a history of frequent exacerbations. The study assessed the effect of roflumilast on COPD exacerbation rate in patients treated with fixed combinations of LABA and inhaled corticosteroids, compared to placebo. A total of 1935 patients were randomised to double-blind medication and approximately 70% were also using a long-acting muscarinic antagonist (LAMA) through the course of the trial. The primary endpoint was reduction in rate of moderate or severe COPD exacerbations per patient per year. The rate of severe COPD exacerbations and changes in FEV1 were evaluated as key secondary endpoints.
Table 2. Summary of COPD exacerbation endpoints in Study RO-2455-404-RD
| Exacerbation Category | Analysis model | Roflumilast (N=969) Rate (n) | Placebo (N=966) Rate (n) | Ratio Roflumilast/Placebo | 2-Sided p-value |
| Rate Ratio | Change (%) | 95% CI |
| Moderate or severe | Poisson regression | 0.805 (380) | 0.927 (432) | 0.868 | -13.2 | 0.753, 1.002 | 0.0529 |
| Moderate | Poisson regression | 0.574 (287) | 0.627 (333) | 0.914 | -8.6 | 0.775, 1.078 | 0.2875 |
| Severe | Negative binomial regression | 0.239 (151) | 0.315 (192) | 0.757 | -24.3 | 0.601, 0.952 | 0.0175 |
There was a trend towards a reduction in moderate or severe exacerbations in subjects treated with roflumilast compared with placebo over 52 weeks, which did not achieve statistical significance (Table 2). A pre-specified sensitivity analysis using the negative binomial regression model treatment showed a statistically significant difference of -14.2% (rate ratio: 0.86; 95% CI: 0.74 to 0.99).
The per-protocol Poisson regression analysis and the non-significant sensitivity to drop-out Poisson regression intention-to-treat analysis rate ratios were 0.81 (95% CI: 0.69 to 0.94) and 0.89 (95% CI: 0.77 to 1.02), respectively.
Reductions were achieved in the subgroup of patients concomitantly treated with LAMA (rate ratio: 0.88; 95% CI: 0.75 to 1.04) and in the subgroup not treated with LAMA (rate ratio: 0.83; 95% CI: 0.62 to 1.12).
The rate of severe exacerbations was reduced in the overall patient group (rate ratio: 0.76; 95% CI: 0.60 to 0.95) with a rate of 0.24 per patient/year compared to a rate of 0.32 per patient/year in patients treated with placebo. A similar reduction was achieved in the subgroup of patients concomitantly treated with LAMA (rate ratio: 0.77; 95% CI: 0.60 to 0.99) and in the subgroup not treated with LAMA (rate ratio: 0.71; 95% CI: 0.42 to 1.20).
Roflumilast improved lung function after 4 weeks (sustained over 52 weeks). Post-bronchodilator FEV1 increased for the roflumilast group by 52 mL (95% CI: 40, 65 mL) and decreased for the placebo group by 4 mL (95% CI: -16, 9 mL). Post-bronchodilator FEV1 showed a clinically significant improvement in favour of roflumilast by 56 mL over placebo (95% CI: 38, 73 mL).
Seventeen (1.8%) patients in the roflumilast group and 18 (1.9%) patients in the placebo group died during the double-blind treatment period due to any reason and 7 (0.7%) patients in each group due to a COPD exacerbation. The proportion of patients who experienced at least 1 adverse event during the double-blind treatment period were 648 (66.9%) patients and 572 (59.2%) patients in the roflumilast and placebo groups, respectively. The observed adverse reactions for roflumilast in Study RO-2455-404-RD were in line with those already included in section 4.8.
More patients in the roflumilast group (27.6%) than placebo (19.8%) withdrew study medication due to any reason (risk ratio: 1.40; 95% CI: 1.19 to 1.65). The major reasons for trial discontinuation were withdrawal of consent and reported adverse events.
Starting dose titration trial
The tolerability of roflumilast was evaluated in a 12-week randomised, double-blind, parallel group trial (RO-2455-302-RD) in patients with severe COPD associated with chronic bronchitis. At screening, patients were required to have had at least one exacerbation in the previous year and on standard of care COPD maintenance treatment for at least 12 weeks. A total of 1323 patients were randomised to receive roflumilast 500 micrograms once a day for 12 weeks (n=443), roflumilast 500 micrograms every other day for 4 weeks followed by roflumilast 500 micrograms once a day for 8 weeks (n=439), or roflumilast 250 micrograms once a day for 4 weeks followed by roflumilast 500 micrograms once a day for 8 weeks (n=441).
Over the entire study period of 12 weeks, the percentage of patients discontinuing treatment due to any reason was statistically significantly lower in patients initially receiving roflumilast 250 micrograms once a day for 4 weeks followed by roflumilast 500 micrograms once a day for 8 weeks (18.4%) compared to those receiving roflumilast 500 micrograms once a day for 12 weeks (24.6%; Odds Ratio 0.66, 95% CI [0.47, 0.93], p=0.017). The discontinuation rate for those receiving 500 micrograms every other day for 4 weeks followed by 500 micrograms once a day for 8 weeks was not statistically significantly different to those receiving 500 micrograms once a day for 12 weeks. The percentage of patients experiencing a Treatment Emergent Adverse Event (TEAE) of interest, defined as diarrhoea, nausea, headache, decreased appetite, insomnia, and abdominal pain (secondary endpoint), was nominally statistically significantly lower in patients initially receiving roflumilast 250 micrograms once a day for 4 weeks followed by roflumilast 500 micrograms once a day for 8 weeks (45.4%) compared to those receiving roflumilast 500 micrograms once a day for 12 weeks (54.2%, Odds Ratio 0.63, 95% CI [0.47, 0.83], p=0.001). The rate of experiencing a TEAE of interest for those receiving 500 micrograms every other day for 4 weeks followed by 500 micrograms once a day for 8 weeks was not statistically significantly different to those receiving 500 micrograms once a day for 12 weeks.
Patients receiving a 500 micrograms dose once a day had a median PDE4 inhibitory activity of 1.2 (0.35, 2.03) and those receiving a 250 micrograms dose once a day had a median PDE4 inhibitory activity of 0.6 (0.20, 1.24). Long-term administration at the 250 micrograms dose level may not induce sufficient PDE4 inhibition to exert clinical efficacy. 250 micrograms once a day is a sub-therapeutic dose, and should be used only as a starting dose for the first 28 days (see sections 4.2 and 5.2).
Paediatric population
The European Medicines Agency has waived the obligation to submit the results of studies with roflumilast in all subsets of the paediatric population in chronic obstructive pulmonary disease (see section 4.2 for information on paediatric use).