Effect of off-label targeted drugs on long-term survival in chronic thromboembolic pulmonary hypertension: Insights from a national multicentre prospective registry.

Background And Objective: Off-label pulmonary arterial hypertension (PAH)-targeted drugs are commonly prescribed for non-operated chronic thromboembolic pulmonary hypertension (CTEPH), but their effect on the long-term prognosis of CTEPH remains unknown. This study investigated the effect of off-label PAH-targeted drugs on the long-term survival of CTEPH patients.

Methods: CTEPH patients were enrolled from a prospective multicentre national registry. Except for licensed riociguat and treprostinil, other PAH-targeted drugs were off-label. In the original and propensity score-matched (PSM) samples, five-year survival was compared in two groups: (a) patients not receiving off-label PAH-targeted drugs (control) versus (b) patients receiving off-label PAH-targeted drugs (treatment). The latter group was investigated for the effect of started off-label PAH-targeted drugs at baselines (initial) or during follow-up (subsequent).

Results: Of 347 enrolled patients, 212 were treated with off-label PAH-targeted drugs initially (n = 173) or subsequently (n = 39), and 135 were untreated. The 1-, 2-, 3- and 5-year survival of the treatment group was significantly higher than that of the control group (97.1% vs. 89.4%, 92.3% vs. 82.1%, 83.2% vs. 75.1% and 71.1% vs. 55.3%, respectively, log-rank test, p = 0.005). Initial treatment was correlated with better 5-year survival after excluding patients with subsequent treatment to reduce the immortal-time bias (hazard ratio: 0.611; 95% CI: 0.397-0.940; p = 0.025). In PSM samples, patients given initial treatment showed significantly better 5-year survival than untreated patients (68.9% vs. 49.3%, log-rank test, p = 0.008).

Conclusion: Off-label targeted drugs contributed to improved long-term survival in CTEPH patients receiving pharmacotherapies.