Clinical Overview: Furosemide Injection (Furoscix) for Subcutaneous Use Treating Heart Failure

Background

Heart failure affects more than 6 million US adults and is estimated to contribute $30.7 billion in health care costs, with this number expected to at least double by 2030.¹ A majority of these costs can be attributed to hospital admissions, which is compounded by associated indirect costs, such as absenteeism, physical limitations, and disease burden.

In an effort to limit hospitalizations, and thus heart failure-related health care costs, subcutaneous (SC) furosemide (Furoscix) was developed as an alternative to intravenous (IV) diuretic therapy. By using an on-body delivery system, the subject can receive parenteral furosemide via the SC route without being in a hospital setting.

Indication

In October 2022, scPharmaceuticals Inc. received FDA approval forFuroscix, the first self-administered, SC loop diuretic. Furoscixis indicated to treat congestion due to fluid overload in patients with NYHA Class II/III chronic heart failure.²

Mechanism of Action

Furosemide exhibits diuretic action by inhibiting sodium and chloride reabsorption in the proximal and distal tubules and the loop of Henle. When administered SC, the bioavailability is maintained (F = 99.6%), producing similar effects as IV administration.²

Dosing and Administration

Furoscixis administered via an on-body delivery system pre-programmed to deliver 80 mg of furosemide subcutaneously more than 5 hours. The system utilizes bi-phasic delivery, with 30 mg delivered over the first hour, followed by 12.5 mg per hour for 4 hours. The infusion timing was developed to mimic IV administration of two 40 mg bolus doses separated by 2 hours.²

Dose Adjustments

The delivery system is preprogrammed; therefore, the dose cannot be adjusted.²

Contraindications

Anuria, hypersensitivity to furosemide or medical adhesives, hepatic cirrhosis, or ascites.²

Common Adverse Effects

Infusion site reactions (bruising, hemorrhage, pain), urinary tract infection, muscle spasms, and dizziness.²

Efficacy

Economic impact was assessed based on the preliminary results from the FREEDOM-HF trial, a phase 3, non-randomized, propensity-matched, clinical trial.³

Primary Outcome

Difference in overall and heart failure-related health care costs between the Furoscix Infusor and the propensity-matched (treatment as usual) control:

• 95% CI (-22187.9 to -11082.7), p<0.0001
• The difference in health care costs was statistically significant.
• The Furoscix Infusor associated with $16,995.30 less heart failure-related costs and $27,840.50 less overall health care costs compared to the control arm.

Secondary Outcomes

Hospital admissions at 30 days:

• p=0.5856
• There was no statistically significant difference in hospital admissions, with the Furoscix Infusor group having 5.3% more hospital admissions than the control.

Heart failure-related emergency department (ED) visits at 30 days:

• p=1
• There was no statistically significant difference in ED visits, with the Furoscix Infusor group having 1.9% less ED visits than the control arm.

Health-related quality of life measured by the self-reported Kansas City Cardiomyopathy Questionnaire (KCCQ) at 30 days:

• 95% CI (0.4 to 25.3), p=0.0443
• The difference in KCCQ scores was statistically significant, with the Furoscix Infusor arm averaging 12.8 more points than the control arm, reflecting a better quality of life.

About the Author

Abby Leitch, PharmD candidate 2023, University of Minnesota.

Preceptor

Chelsea Morken, PharmD, PGY2 ambulatory care pharmacy resident, Mayo Clinic Health System – Mankato.

References

1. Patel J. Heart Failure Population Health Considerations. Am J Manag Care 2021; 27(suppl 9):S191-195.
2. Product Information: Furoscix, furosemide injection. [package insert]. scPharmaceuticals, Inc., Burlington, MA, 2022.
3. scPharmaceuticals, Inc. (2020, November 12 - 2021, June 24). Furoscix Real-World Evaluation for Decreasing Hospital Admissions in Heart Failure (FREEDOM-HF). Identifier NCT03458325. https://clinicaltrials.gov/ct2/show/study/NCT03458325