Evaluating Right Ventricular Stroke Volume and Pulmonary Vascular Resistance in PAH

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Evaluating Right Ventricular Stroke Volume and Pulmonary Vascular Resistance in PAH



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Explore data on a treatment option’s effect on right ventricular stroke volume and pulmonary vascular resistance in patients with PAH.

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  • Overview

    Pulmonary arterial hypertension (PAH) is a rare disease with a traditionally poor prognosis.1-2 Given the progressive nature of PAH,3 it’s important to advance clinical understanding of the effects of available treatment options. In this program, pulmonologist Dr. Richard Channick joins ReachMD host Dr. Randy Young to share data from the REPAIR study, an open-label, single-arm, Phase 4 study that evaluated the effect of OPSUMIT® (macitentan) on right ventricular stroke volume and pulmonary vascular resistance in patients with PAH.Please see Important Safety Information below and full Prescribing Information, including BOXED WARNING.

    Dr. Randy Young is a paid consultant for ReachMD, and Dr. Richard Channick is a paid consultant for the Janssen Pharmaceutical Companies of Johnson & Johnson.


    1. Pulmonary Arterial Hypertension. National Organization of Rare Disorders. Updated 2021. Accessed September 21, 2021.
    2. Kylhammar D, Kjellström B, Hjalmarsson C, et al. A comprehensive risk stratification at early follow-up determines prognosis in pulmonary arterial hypertension, Eur Heart Journal. 2018;39(47):4175–4181.
    3. Lai Y-C, Potoka KC, Champion HC, et al. Pulmonary arterial hypertension: the clinical syndrome. Circ Res. 2014;115(1):115-130.
    4. Vonk Noordegraaf A, Channick R, Cottreel E, et al. The REPAIR study: Effects of macitentan on RV structure and function in pulmonary arterial hypertension. JACC Cardiovasc Imaging. 2021;S1936-878X(21)00635-5 and suppl 1-15. doi:10.1016/j.jcmg.2021.07.027.

    © 2022 Actelion Pharmaceuticals US, Inc. All rights reserved. cp-196991v1 06/22 


    OPSUMIT® is an endothelin receptor antagonist (ERA) indicated for the treatment of pulmonary arterial hypertension (PAH, WHO Group I) to reduce the risks of disease progression and hospitalization for PAH. 

    Effectiveness was established in a long-term study in PAH patients with predominantly WHO Functional Class II-III symptoms treated for an average of 2 years. Patients had idiopathic and heritable PAH (57%), PAH caused by connective tissue disorders (51%), and PAH caused by congenital heart disease with repaired shunts (8%).



    • Do not administer OPSUMIT® to a pregnant female because it may cause fetal harm.
    • Females of reproductive potential: Exclude pregnancy before the start of treatment, monthly during treatment, and 1 month after stopping treatment. Prevent pregnancy during treatment and for one month after stopping treatment by using acceptable methods of contraception.
    • For all female patients, OPSUMIT® is available only through a restricted program called the OPSUMIT® Risk Evaluation and Mitigation Strategy (REMS).

    Pregnancy: OPSUMIT® may cause fetal harm when administered to a pregnant woman. OPSUMIT® is contraindicated in females who are pregnant. If OPSUMIT® is used during pregnancy, advise the patient of the potential risk to a fetus.

    Hypersensitivity: OPSUMIT® is contraindicated in patients with a history of a hypersensitivity reaction to macitentan or any component of the product.

    Embryo-fetal Toxicity and OPSUMIT® REMS Program
    Due to the risk of embryo-fetal toxicity, OPSUMIT® is available for females only through a restricted program called the OPSUMIT® REMS Program. For females of reproductive potential, exclude pregnancy prior to initiation of therapy, ensure use of acceptable contraceptive methods, and obtain monthly pregnancy tests.

    Notable requirements of the OPSUMIT® REMS Program include:

    • Prescribers must be certified with the program by enrolling and completing training.
    • All females, regardless of reproductive potential, must enroll in the OPSUMIT® REMS Program prior to initiating OPSUMIT®. Male patients are not enrolled in the REMS.
    • Females of reproductive potential must comply with the pregnancy testing and contraception requirements.
    • Pharmacies must be certified with the program and must only dispense to patients who are authorized to receive OPSUMIT®.


    • ERAs have caused elevations of aminotransferases, hepatotoxicity, and liver failure. The incidence of elevated aminotransferases in the SERAPHIN study >3 x ULN was 3.4% for OPSUMIT® vs 4.5% for placebo, and >8 x ULN was 2.1% vs 0.4%, respectively. Discontinuations for hepatic adverse events were 3.3% for OPSUMIT® vs 1.6% for placebo.
    • Obtain liver enzyme tests prior to initiation of OPSUMIT® and repeat during treatment as clinically indicated.
    • Advise patients to report symptoms suggesting hepatic injury (nausea, vomiting, right upper quadrant pain, fatigue, anorexia, jaundice, dark urine, fever, or itching).
    • If clinically relevant aminotransferase elevations occur, or if elevations are accompanied by an increase in bilirubin >2 x ULN, or by clinical symptoms of hepatotoxicity, discontinue OPSUMIT®. Consider re-initiation of OPSUMIT® when hepatic enzyme levels normalize in patients who have not experienced clinical symptoms of hepatotoxicity.

    Fluid Retention

    • Peripheral edema and fluid retention are known consequences of PAH and ERAs. In the pivotal PAH study SERAPHIN, edema was reported in 21.9% of the OPSUMIT® group vs 20.5% for placebo.
    • Patients with underlying left ventricular dysfunction may be at particular risk for developing significant fluid retention after initiation of ERA treatment. In a small study of pulmonary hypertension due to left ventricular dysfunction, more patients in the OPSUMIT® group developed significant fluid retention and had more hospitalizations due to worsening heart failure compared to placebo. Postmarketing cases of edema and fluid retention occurring within weeks of starting OPSUMIT®, some requiring intervention with a diuretic or hospitalization for decompensated heart failure, have been reported.
    • Monitor for signs of fluid retention after OPSUMIT® initiation. If clinically significant fluid retention develops, evaluate the patient to determine the cause and the possible need to discontinue OPSUMIT®.

    Hemoglobin Decrease

    • Decreases in hemoglobin concentration and hematocrit have occurred following administration of other ERAs and in clinical studies with OPSUMIT®. These decreases occurred early and stabilized thereafter.
    • In the SERAPHIN study, OPSUMIT® caused a mean decrease in hemoglobin (from baseline to 18 months) of about 1.0 g/dL vs no change in the placebo group. A decrease in hemoglobin to below 10.0 g/dL was reported in 8.7% of the OPSUMIT® group vs 3.4% for placebo. Decreases in hemoglobin seldom require transfusion.
    • Initiation of OPSUMIT® is not recommended in patients with severe anemia. Measure hemoglobin prior to initiation of treatment and repeat during treatment as clinically indicated.

    Pulmonary Edema with Pulmonary Veno-occlusive Disease (PVOD)
    Should signs of pulmonary edema occur, consider the possibility of associated PVOD. If confirmed, discontinue OPSUMIT®.

    Decreased Sperm Counts
    OPSUMIT®, like other ERAs, may have an adverse effect on spermatogenesis. Counsel men about potential effects on fertility.

    Most common adverse reactions (more frequent than placebo by ≥3%) were anemia (13% vs 3%), nasopharyngitis/pharyngitis (20% vs 13%), bronchitis (12% vs 6%), headache (14% vs 9%), influenza (6% vs 2%), and urinary tract infection (9% vs 6%).


    • Strong inducers of CYP3A4 such as rifampin significantly reduce macitentan exposure. Concomitant use of OPSUMIT® with strong CYP3A4 inducers should be avoided.

    • Strong inhibitors of CYP3A4 like ketoconazole approximately double macitentan exposure. Many HIV drugs like ritonavir are strong inhibitors of CYP3A4. Avoid concomitant use of OPSUMIT® with strong CYP3A4 inhibitors. Use other PAH treatment options when strong CYP3A4 inhibitors are needed as part of HIV treatment.

    • Moderate dual inhibitors of CYP3A4 and CYP2C9 such as fluconazole and amiodarone are predicted to increase macitentan exposure. Avoid concomitant use of OPSUMIT® with moderate dual inhibitors of CYP3A4 and CYP2C9.

    • Concomitant treatment of both a moderate CYP3A4 inhibitor and moderate CYP2C9 inhibitor with OPSUMIT® should also be avoided.

    Please see full Prescribing Information, including BOXED WARNING.


Schedule1 Jun 2023