Spinal muscular atrophy (SMA) gene therapy & drug cost calculator

Spinal muscular atrophy (SMA) gene therapy & drug cost calculator helps estimate Korea-related chronic treatment, biologic drug, dialysis, obesity medication, and long-term management assumptions in English.

Health cost scenario inputs

Enter Korea-related chronic care, eldercare, therapy, procedure, fertility, diagnostic, or medical tourism assumptions. Results are simplified planning estimates.

Treatment cost over period

₩18,000,000

Monitoring or support cost

₩1,500,000

Increase reserve

₩1,440,000

Planning window cost

₩20,940,000

36 months

This English page is a simplified Korea-related health, eldercare, therapy, chronic disease, fertility, non-covered care, or medical tourism planning estimate. It is not medical advice and does not replace diagnosis, treatment decisions, insurer review, hospital quotes, or government benefit decisions.

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What is spinal muscular atrophy (SMA) gene therapy?

Spinal muscular atrophy (SMA) is an autosomal-recessive genetic disease in which a loss or mutation of the SMN1 gene destroys motor neurons in the spinal cord, causing progressive muscle weakness and wasting.
Without treatment most infants with the common Type 1 form died before age two, but three ultra-expensive drugs have since transformed the outlook, and all three are reimbursed by Korea’s National Health Insurance.

This calculator estimates the list drug cost of Korea’s three SMA therapies — Zolgensma (a one-time gene therapy), Spinraza (an intrathecal injection), and Evrysdi (an oral drug) — and the real out-of-pocket burden after the rare-disease copay special case (10%), the annual out-of-pocket ceiling, the medical-cost support program, and the medical-expense tax credit, on a 2026 basis.
Its core purpose is to compare a “one-time gene therapy” against “lifelong repeated treatment” by cumulative real out-of-pocket, not by sticker price.

Korea-based estimate. This calculator is built on Korean National Health Insurance rules for 2026 (rare-disease special-copay registration, the annual out-of-pocket ceiling, and the KDCA rare-disease medical-cost support program). It is an educational estimate, not medical advice, and does not replace genetic testing, a diagnosis, a hospital quote, pre-authorization review, or an insurer/benefit decision.

The three SMA therapies

① Zolgensma (onasemnogene abeparvovec) — one-time gene therapy

Zolgensma delivers a working SMN1 gene to motor neurons using an AAV9 viral vector.
It is given once in a lifetime as a single IV infusion, and has been reimbursed in Korea since August 1, 2022.

  • • Dose: 1.1×10¹⁴ vector genomes per kg body weight; Korean reimbursement is a fixed per-kit price (about KRW 1,981,700,000)
  • • Coverage indication: biallelic 5q SMN1 deletion/mutation plus clinical Type 1 SMA (or switching from prior treatment), given under 24 months of age and body weight under 13.5 kg
  • • Management: risk-sharing agreement (RSA), performance-based refund, 5-year long-term follow-up consent, pre-authorization before infusion

② Spinraza (nusinersen) — intrathecal injection, lifelong

Spinraza is an antisense oligonucleotide (ASO) that promotes SMN2 exon-7 inclusion to raise functional SMN protein.
It is injected intrathecally by lumbar puncture and has been reimbursed in Korea since April 8, 2019.

  • • Schedule: 4 loading doses (days 0, 14, 28, 63, over ~2 months), then maintenance every 4 months
  • • Doses per year: 6 in year 1 (4 loading + 2 maintenance), then 3 per year for life
  • • Price: about KRW 92.35 million per 5 mL vial; motor-function must be shown to be maintained/improved every 4 months to keep coverage

③ Evrysdi (risdiplam) — the only oral drug, lifelong daily

Evrysdi is an oral SMN2 splicing modifier that crosses the blood-brain barrier and acts throughout the body.
It is taken once daily and, since October 2023, is the only oral SMA drug reimbursed in Korea.

  • • Weight-based dose: 0.2 mg/kg (2 months–2 years), 0.25 mg/kg (≥2 years, under 20 kg), 5 mg/day flat (20 kg and over)
  • • Formulation: 60 mg / 80 mL bottle (0.75 mg/mL), used within 64 days of constitution
  • • Price: about KRW 9.52 million per bottle; annual cost follows the number of bottles per year set by weight

One-time vs lifelong: why compare cumulative cost?

The out-of-pocket ceiling applies on an annual basis.
However large a year’s covered out-of-pocket is, you pay only up to your income-decile cap and the rest is refunded.

So Zolgensma hits the cap only once (the year of infusion) and then has no further drug cost, while Spinraza and Evrysdi hit the cap every year for life.
By sticker price Zolgensma (about KRW 2 billion once) looks far more expensive, but over 10 or 20 years the cumulative real burden of lifelong therapy grows past it.

Zolgensma cumulative real out-of-pocket ≈ 1 × income-decile ceiling (once)
Spinraza / Evrysdi cumulative real out-of-pocket ≈ N × income-decile ceiling (yearly)

For a decile-5 patient (annual cap about KRW 1.73 million), Zolgensma’s 10-year real burden is roughly KRW 1.73 million, whereas lifelong therapy runs to roughly KRW 17.3 million (1.73M × 10).
That is why this calculator headlines cumulative real out-of-pocket rather than the sticker price.

How the cost is calculated

1. List drug cost by therapy

Zolgensma = fixed per-kit price (one time)
Spinraza = 6 doses × price (year 1), 3 doses × price (each later year)
Evrysdi = (daily mg × 365 ÷ 60 mg) bottles × price per bottle

Evrysdi’s daily dose varies with weight, so its annual bottle count — and cost — changes as the patient grows.
All three drugs are under risk-sharing / performance-based refund contracts, so real prices may be confidential; you can adjust each price in the calculator.

2. Covered out-of-pocket and safety nets

covered out-of-pocket = list cost × coinsurance (10% or 30%)
− out-of-pocket ceiling refund (excess over the annual cap)
− rare-disease medical-cost support (if eligible)
− medical-expense tax credit (15% of the part above 3% of salary)
= real out-of-pocket

The three safety nets that cut your cost

① Rare-disease special copay (10% coinsurance)

SMA is a registered rare-disease special-case condition — diagnosis codes G12.0 (infantile SMA type I, Werdnig-Hoffmann) and G12.1 (other inherited SMA), special mark V123.
Once registered, the patient pays only 10% of covered charges (versus 30% outpatient without registration).

Basis: National Health Insurance Act Art. 44 and Enforcement Decree Art. 19(1) Table 2, and the Ministry of Health and Welfare Notice on Copayment Special Cases (No. 2026-101), Art. 5 and Table 4.
Registration lasts 5 years and can be renewed while the disease persists.

② Out-of-pocket ceiling (annual cap, retroactive refund)

When annual covered out-of-pocket exceeds the income-decile ceiling, the excess is refunded.
Even at the 10% special-case rate, SMA out-of-pocket runs into the millions or more, so the ceiling is the key mechanism that pulls the real burden down to the income-decile cap.

For 2026 the income-decile annual ceiling ranges from about KRW 900,000 (decile 1) to KRW 8,430,000 (decile 10).
Because it applies per year, Zolgensma reaches the cap only in the year of infusion, while lifelong therapy reaches it every year.

③ Rare-disease medical-cost support

The KDCA rare-disease helpline runs a medical-cost support program that covers covered-care out-of-pocket for registered patients who meet income and asset tests.

SMA is not one of the four special conditions (hemophilia, Gaucher, Fabry, mucopolysaccharidosis), so the general rare-disease income limit applies (patient household under about 140% of median income).
If eligible, the remaining out-of-pocket after the special-case rate (and the ceiling) can also be supported; check eligibility at helpline.kdca.go.kr.

Frequently asked questions

Q. Is Zolgensma really about KRW 2 billion?

A. Yes — before coverage Zolgensma costs about KRW 2 billion and is called the “most expensive drug in the world.”
Since its August 2022 reimbursement, the 10% special-case rate plus the out-of-pocket ceiling bring the real one-time burden down to the income-decile cap (a few million won).

Q. Zolgensma has the highest sticker price, so why is its cumulative real cost lower?

A. Because the out-of-pocket ceiling applies annually.
Zolgensma reaches the cap once, whereas Spinraza and Evrysdi reach it every year, so over time the caps stack up for lifelong therapy.

Q. Can anyone receive Zolgensma?

A. No. Coverage requires confirmed biallelic 5q SMN1 deletion/mutation and clinical Type 1 SMA (or switching from prior treatment), given under 24 months of age and under 13.5 kg.
Above these limits, Spinraza or Evrysdi are the realistic options, and the final indication is set by genetic testing and pre-authorization review.

Q. Can I also claim the medical-expense tax credit?

A. With earned income you get a 15% credit on out-of-pocket above 3% of total salary.
For a registered rare/intractable-disease patient’s own expenses, the credit has no KRW 7 million cap.

Estimate your SMA treatment cost now

Enter the therapy, weight, and coverage settings to see how far the very high drug cost falls after Korea’s safety nets, and to compare a one-time gene therapy against lifelong treatment by cumulative real out-of-pocket.

This is a 2026 reference estimate; confirm actual prices, indications, and out-of-pocket with your hospital and the National Health Insurance Service.