Ensifentrine

12.1 Mechanism of Action Ensifentrine is a small molecule that is an inhibitor of the PDE3 and PDE4 enzymes. PDE3 primarily hydrolyzes the second-messenger molecule cyclic adenosine monophosphate (cAMP) but is also capable of hydrolyzing cyclic guanosine monophosphate (cGMP). PDE4 hydrolyzes cAMP only. Inhibition of PDE3 and PDE4 results in accumulation of intracellular levels of cAMP and/or cGMP, resulting in various downstream signalling effects.

1 INDICATIONS AND USAGE OHTUVAYRE is indicated for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adult patients. OHTUVAYRE is a phosphodiesterase 3 (PDE3) inhibitor and phosphodiesterase 4 (PDE4) inhibitor indicated for the maintenance treatment of chronic obstructive pulmonary disease (COPD) in adult patients. ( 1 )

2 DOSAGE AND ADMINISTRATION The recommended dosage of OHTUVAYRE is 3 mg (one unit-dose ampule) twice daily, once in the morning and once in the evening, administered by oral inhalation using a standard jet nebulizer with a mouthpiece. Recommended Dosage : 3 mg (one ampule) twice daily administered by oral inhalation using a standard jet nebulizer with a mouthpiece. ( 2 ) See full prescribing information for administration instructions. ( 2 ) Administration Instructions Remove OHTUVAYRE unit-dose ampule from foil pouch only immediately before use. For pouches of 5 ampules, remove one ampule and place the remaining ampules back into the pouch until next use. Once the foil pouch is opened, discard ampules if not used within 14 days. Shake OHTUVAYRE ampule vigorously. Squeeze and completely empty contents of the ampule into the nebulizer cup for administration of OHTUVAYRE by oral inhalation. Discard ampule with any residual content. Administer OHTUVAYRE by oral inhalation using a standard jet nebulizer equipped with a mouthpiece, connected to an air compressor [see Instructions for Use ] . Drug Compatibility Compatibility of OHTUVAYRE mixed with other drugs has not been established. OHTUVAYRE should not be physically mixed with other drugs or added to solutions containing other drugs.

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: Paradoxical Bronchospasm [see Warnings and Precautions (5.2) ] Psychiatric Events Including Suicidality [see Warnings and Precautions (5.3) ] Most common adverse reactions (incidence greater and equal to 1% and more common than placebo) include back pain, hypertension, urinary tract infection, and diarrhea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Verona Pharma at 888-672-0371 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of OHTUVAYRE was based on the pooled safety population from two randomized, double-blind, placebo-controlled trials (ENHANCE-1 and ENHANCE-2) for 24 weeks, and a 48-week cohort that assessed safety in ENHANCE-1. In these trials, a total of 975 patients received 3 mg of OHTUVAYRE twice daily administered by oral inhalation using a standard jet nebulizer [see Clinical Studies (14) ] . The safety population included all patients who were randomized and received at least one dose of OHTUVAYRE or placebo. Adverse reactions that occurred at an incidence greater than or equal to 1% in OHTUVAYRE and were more common than placebo in the pooled population are provided in Table 1. The proportion of patients who discontinued treatment due to adverse reactions was 7.6% for the OHTUVAYRE-treated patients and 8.2% for placebo-treated patients. Table 1. Adverse Reactions with OHTUVAYRE with incidence ≥ 1% and More Common than Placebo in Patients with COPD in the Pooled 24-Week Safety Population (ENHANCE-1 and ENHANCE-2) Adverse Reaction OHTUVAYRE N=975 n (%) Placebo N=574 n (%) Back pain 18 (1.8%) 6 (1.0%) Hypertension 17 (1.7%) 5 (0.9%) Urinary tract infection 13 (1.3%) 6 (1.0%) Diarrhea 10 (1.0%) 4 (0.7%) Adverse Reactions in the 48-Week Cohort In the 48-week cohort of ENHANCE-1, 369 patients were enrolled to be treated with 3 mg OHTUVAYRE (N=280) or placebo (N=89) twice daily for 48 weeks [see Clinical Studies (14) ] . The adverse reactions reported in the 48-week cohort were consistent with those observed in the pooled 24-week safety population.