What is the most expensive medical injection?

October 5, 2025 •

4 min read

With a price tag of $4.25 million, Lenmeldy holds the title for the world's most expensive medical injection [1.4.2]. This one-time gene therapy treats metachromatic leukodystrophy (MLD), a rare, fatal genetic disorder affecting about one in 40,000 Americans [1.4.2, 1.7.6].

Quick Summary

The world's most expensive medical injections are dominated by one-time gene therapies for rare diseases. Lenmeldy, at $4.25 million, tops the list, followed by Hemgenix ($3.5M) and Elevidys ($3.2M).

Key Points

The Most Expensive: Lenmeldy is the world's most expensive medical injection, priced at $4.25 million for a one-time treatment [1.4.2].
Condition Treated: Lenmeldy is a gene therapy for metachromatic leukodystrophy (MLD), a rare, fatal childhood genetic disorder [1.4.1].
Gene Therapy Dominance: The list of most expensive drugs is dominated by one-time gene therapies for rare diseases, including Hemgenix ($3.5M) and Elevidys ($3.2M) [1.7.4].
High Development Costs: The extreme prices are driven by high R&D costs, complex manufacturing, and very small patient populations [1.6.1, 1.6.7].
Value-Based Justification: Manufacturers argue the prices are justified by the long-term value and cost savings compared to a lifetime of chronic care [1.3.3, 1.5.7].
Future of Payment: The high cost of these therapies is pushing for innovative payment models, like outcomes-based agreements and pay-over-time options [1.4.5, 1.5.2].

The New Frontier of Multi-Million Dollar Medications

The landscape of pharmaceuticals has been radically altered by the advent of gene therapies. These groundbreaking treatments, which often offer a one-time, potentially curative solution for devastating genetic disorders, command the highest prices in medical history [1.6.5]. As of 2025, the distinction of the world's most expensive medical injection belongs to Lenmeldy, a gene therapy from Orchard Therapeutics priced at a staggering $4.25 million for a single dose [1.4.1, 1.4.2].

Lenmeldy is the first FDA-approved treatment for children with early-onset metachromatic leukodystrophy (MLD) [1.4.1]. MLD is an ultra-rare and fatal inherited metabolic disease caused by the deficiency of an enzyme called arylsulfatase A (ARSA) [1.4.6]. This deficiency leads to a toxic buildup of fatty substances (sulfatides) in the cells, particularly in the brain and nervous system, causing rapid loss of motor and cognitive function, and ultimately, death [1.4.6, 1.7.6]. In clinical trials, Lenmeldy demonstrated a significant reduction in the risk of severe motor impairment or death, with all treated children alive at age six, compared to only 58% in an untreated control group [1.4.6].

The Contenders: A League of Extraordinary Treatments

While Lenmeldy currently holds the top spot, it is part of a growing class of multi-million dollar, single-use gene therapies. These treatments represent a paradigm shift from chronic management to upfront, curative potential.

Hemgenix: A $3.5 Million Hope for Hemophilia B

Before Lenmeldy's approval, Hemgenix held the title of the world's most expensive drug [1.7.6]. Priced at $3.5 million, this one-time gene therapy is approved for adults with hemophilia B, a rare genetic bleeding disorder caused by a lack of clotting Factor IX [1.3.1, 1.3.2, 1.3.4]. Patients with hemophilia B are vulnerable to life-threatening bleeding and often require lifelong, frequent infusions of Factor IX to manage their condition [1.3.5]. Hemgenix works by using a modified virus to deliver a functional gene to the liver, enabling the patient's body to produce its own Factor IX [1.3.6]. The manufacturer, CSL Behring, argues the high price is justified by the potential to save the healthcare system millions over a patient's lifetime by eliminating the need for chronic, expensive prophylactic treatments [1.3.3]. The estimated lifelong cost for severe hemophilia B can be as high as $20 million [1.3.1].

Other Notable High-Cost Injections

The list of therapies with seven-figure price tags continues to grow, each targeting a rare and severe condition:

Elevidys: Priced at $3.2 million, this is a gene therapy for Duchenne muscular dystrophy (DMD), a progressive muscle-wasting disorder [1.7.4, 1.7.6].
Skysona: This $3.0 million one-time gene therapy treats cerebral adrenoleukodystrophy (CALD), a rare neurological disorder affecting young boys [1.2.7, 1.7.4].
Zynteglo: At $2.8 million, this gene therapy is for beta-thalassemia, a genetic blood disorder that requires patients to have lifelong red blood cell transfusions [1.2.2, 1.2.7].
Zolgensma: Once the most expensive drug at $2.1 million, Zolgensma is a one-time treatment for spinal muscular atrophy (SMA), a leading genetic cause of infant mortality [1.2.7, 1.5.4].

Comparison of Top-Tier Medical Injections


Drug Name	List Price (USD)	Condition Treated	Mechanism of Action
Lenmeldy	$4.25 Million	Metachromatic Leukodystrophy (MLD)	One-time gene therapy using patient's own stem cells [1.4.1, 1.7.6]
Hemgenix	$3.5 Million	Hemophilia B	One-time gene therapy to produce Factor IX [1.3.1, 1.3.2]
Elevidys	$3.2 Million	Duchenne Muscular Dystrophy (DMD)	Gene therapy for muscle disorder [1.7.4, 1.7.6]
Skysona	$3.0 Million	Cerebral Adrenoleukodystrophy (CALD)	One-time gene therapy for neurological disorder [1.2.7, 1.7.4]
Zynteglo	$2.8 Million	Beta-Thalassemia	Gene therapy to eliminate need for blood transfusions [1.2.2, 1.2.7]
Zolgensma	$2.1 Million	Spinal Muscular Atrophy (SMA)	One-time gene therapy to replace a faulty gene [1.2.7, 1.5.5]

Why Are Gene Therapies So Expensive?

The multi-million dollar price tags are not arbitrary. They are a result of a confluence of factors unique to gene therapy development:

High Research & Development (R&D) Costs: Developing a gene therapy is a long, complex, and costly process, with estimates suggesting the total cost can be around $5 billion [1.6.7]. This includes extensive preclinical research, manufacturing studies, and multi-phase clinical trials [1.6.6, 1.6.7].
Complex Manufacturing: Unlike traditional chemical drugs, gene therapies involve working with biological materials like viral vectors or patient cells. Manufacturing processes are often manual, highly specialized, and far more expensive, with the cost of goods for a single therapy ranging from $500,000 to $1 million [1.6.3, 1.6.7].
Small Patient Populations: These therapies treat rare or ultra-rare diseases [1.6.1]. With a very small number of potential patients, manufacturers must recoup the massive development costs from a limited market [1.6.7].
Value-Based Pricing: Companies often justify the cost based on the long-term value the therapy provides. For a one-time cure, this value includes the lifetime savings from avoiding chronic treatments, hospitalizations, and caregiver costs, which can run into the tens of millions of dollars [1.3.1, 1.5.2].

Conclusion

The most expensive medical injections are at the cutting edge of medical innovation, offering transformative hope for patients with rare and life-threatening genetic diseases. While the upfront cost of treatments like Lenmeldy is immense, it forces a broader conversation about value, affordability, and the future of healthcare financing. As more gene therapies move through the development pipeline, healthcare systems, insurers, and policymakers will face increasing pressure to create novel payment and reimbursement models that balance rewarding innovation with ensuring patient access to these life-altering medicines [1.4.5, 1.5.2].

For more information on gene therapies, you can visit the National Organization for Rare Disorders (NORD).

Frequently Asked Questions

The most expensive medical injection is Lenmeldy, a one-time gene therapy for the rare genetic disease metachromatic leukodystrophy (MLD), with a list price of $4.25 million [1.4.2].

Lenmeldy treats children with early-onset metachromatic leukodystrophy (MLD), a fatal inherited disease that causes rapid neurological decline and death [1.4.1, 1.4.6].

Before Lenmeldy, Hemgenix was the most expensive drug. It is a gene therapy for hemophilia B priced at $3.5 million [1.7.6].

Yes, the top of the list for most expensive drugs is dominated by one-time, single-dose gene therapies designed to treat rare genetic conditions [1.2.2, 1.7.4].

Gene therapies are expensive due to a combination of factors, including massive research and development costs, complex and costly manufacturing processes, small patient populations for the rare diseases they treat, and a pricing model based on long-term value and healthcare savings [1.6.1, 1.6.7].

Hemgenix is a one-time infusion that uses a harmless viral vector to deliver a functional gene to the liver. This allows patients with hemophilia B to produce their own Factor IX, the clotting protein they are missing [1.3.2].

Coverage can be complex. Manufacturers often work with payers to create innovative reimbursement models, including outcomes-based agreements and pay-over-time options, to facilitate access for patients [1.4.5, 1.5.2]. Some self-insured employers may choose to exclude gene therapies from coverage due to the high cost [1.3.8].