Cell and Gene Therapies: The Million-Dollar Claims That Are No Longer Hypothetical

Kymriah costs $475,000. Yescarta costs $373,000. Breyanzi costs $410,000. Carvykti costs $465,000. Casgevy costs $2.2 million. Roctavian costs $2.9 million. These are not projected pipeline costs. They are current list prices for FDA-approved therapies with claims flowing through commercial insurance today. The drug cost alone does not capture the full exposure. Medicare claims data from 2021 through 2022 documented average total costs for CAR-T therapy of approximately $499,000 per inpatient episode and $413,000 per outpatient episode, including hospitalization, monitoring, and management of adverse effects.

A single claim at these levels exceeds the total annual claims fund for most small group level funded plans. A $2.2 million gene therapy claim in a 25-person plan is not a bad year. It is a structural event that the small group stop loss architecture was never designed to handle.

The Therapies and Their Costs

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CAR-T cell therapies reprogram a patient’s own T cells to recognize and destroy cancer cells. The manufacturing process is individualized: cells are extracted from the patient, genetically modified in a laboratory, expanded in culture over two to four weeks, and reinfused. The cost reflects the manufacturing complexity and the curative intent.

Six CAR-T products are approved in the United States as of early 2026. Four target CD19, a protein on B-cell malignancies: Kymriah (tisagenlecleucel, Novartis) at $475,000 for acute lymphoblastic leukemia and $373,000 for lymphoma; Yescarta (axicabtagene ciloleucel, Gilead/Kite) at $373,000 for large B-cell lymphoma; Tecartus (brexucabtagene autoleucel, Gilead/Kite) at $373,000 for mantle cell lymphoma and ALL; and Breyanzi (lisocabtagene maraleucel, Bristol Myers Squibb) at $410,000 for lymphoma and, as of March 2024, chronic lymphocytic leukemia. Two target BCMA on plasma cells for multiple myeloma: Abecma (idecabtagene vicleucel, Bristol Myers Squibb) at $419,500 and Carvykti (ciltacabtagene autoleucel, Janssen/Legend Biotech) at $465,000.

The drug price understates total episode cost. CAR-T therapy requires two to four weeks of inpatient care at a specialized cancer center. Cytokine release syndrome, a potentially life-threatening inflammatory response, occurs in a significant proportion of patients and may require ICU monitoring. Leukapheresis (cell collection) adds $8,000 to $12,000. Bridging chemotherapy adds $5,000 to $15,000. Pre-screening adds $2,000 to $5,000. Total episode cost, including drug, facility, and professional services, commonly exceeds $500,000 and can reach $1 million for complicated cases.

Gene therapies modify the patient’s genetic material to correct disease-causing mutations. The curative intent and one-time administration justify prices that exceed any prior pharmaceutical category.

Exagamglogene autotemcel (Casgevy), developed by Vertex Pharmaceuticals and CRISPR Therapeutics, treats sickle cell disease and transfusion-dependent beta-thalassemia using CRISPR gene editing. The cost is approximately $2.2 million per treatment. Lovotibeglogene autotemcel (Lyfgenia), developed by Bluebird Bio, treats sickle cell disease at approximately $3.1 million. Valoctocogene roxaparvovec (Roctavian), developed by BioMarin, treats severe hemophilia A at approximately $2.9 million per treatment. Onasemnogene abeparvovec (Zolgensma), developed by Novartis, treats spinal muscular atrophy in infants at $2.25 million.

The Stop Loss Problem

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The stop loss structure was designed for a world where the most expensive individual claims ran $200,000 to $500,000: complicated surgeries, NICU stays, severe trauma. Cell and gene therapies operate at a different order of magnitude.

Consider a 25-person plan with $300,000 in expected annual claims. The specific stop loss attachment point is $75,000. The aggregate attachment point is $375,000 (125 percent of expected). A member receives a $2.9 million gene therapy for hemophilia A.

The specific stop loss mechanism works as designed. The plan’s claims fund pays the first $75,000. The stop loss carrier pays $2,825,000 above the specific deductible, up to the policy limit. If the policy limit is sufficient, the employer’s per-member exposure is capped.

The complication arrives from two directions. First, the $75,000 specific deductible paid from the claims fund, combined with routine claims for the rest of the group, pushes total plan-paid claims toward or through the aggregate corridor. If other claims run at expected levels ($300,000), total plan-paid claims reach $375,000, precisely the aggregate attachment point. Any variance above expected in the rest of the group breaches the aggregate. Second, and more consequentially, the stop loss carrier has just paid a $2.8 million claim against a premium that was set for a 25-person group. No small group stop loss premium anticipates a single claim exceeding $2 million. The carrier’s loss on this policy is catastrophic regardless of how the premium was calculated.

The carrier’s response at renewal is predictable: nonrenewal, or terms so restrictive they amount to the same thing. The employer must find new stop loss coverage with a claims history that includes a multi-million-dollar event. Even if the gene therapy was curative and the member will not generate future claims at that level, the claims history follows the group.

Some stop loss carriers have responded by introducing sublimits for cell and gene therapy claims, capping coverage at $1 million or $2 million per member for this category. Others exclude specific therapies by name. Others require supplemental riders at additional premium. The treatment is inconsistent across carriers including Sun Life, Voya, Symetra, and Tokio Marine HCC, and the inconsistency itself creates a problem for brokers and TPAs advising small group clients. A broker placing a 25-person group with one carrier may discover at claims time that the policy sublimits cell and gene therapy at $1 million, leaving the plan exposed for $1.9 million on a $2.9 million gene therapy claim. The sublimit may appear in rider language or endorsement provisions that receive less scrutiny during the placement process than the headline attachment point and premium.

The policy limit question compounds the exposure. Traditional small group stop loss policies carry aggregate limits of $1 million to $5 million per member, depending on carrier and group size. A $2.9 million gene therapy claim against a $2 million per-member policy limit leaves $900,000 uncovered. The employer is liable for the excess. For a small employer, this is not a financial setback. It is potentially an existential event for the plan and a fiduciary liability for the employer who signed the plan document.

The timing of claims adds another complication. Gene therapies are one-time treatments, but the claims processing may span multiple months. Leukapheresis, bridging chemotherapy, the gene therapy administration, and weeks of post-treatment monitoring generate claims across several billing cycles. If the plan year boundary falls in the middle of a gene therapy episode, claims may split across two plan years, creating coordination issues between the current and renewal stop loss policies.

Emerging Risk Transfer Mechanisms

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Three mechanisms are developing to address cell and gene therapy risk. None is standard or widely available in the small group market.

Manufacturer outcomes-based agreements tie payment to therapeutic success. If the gene therapy does not produce the expected clinical outcome within a defined period, the manufacturer refunds part or all of the cost. Bluebird Bio structured outcomes-based pricing for Lyfgenia. Novartis offered similar terms for Zolgensma. These agreements protect payers when therapies fail. They do not address the cash flow challenge when therapies succeed as intended.

Specialty reinsurance products layer above traditional stop loss to provide catastrophic protection for single claims exceeding defined thresholds. Some reinsurers have developed products specifically for cell and gene therapy exposure, priced as low-probability, high-severity coverage. The structure resembles excess of loss reinsurance rather than traditional stop loss. These products are marketed primarily to large self-funded employers and national TPAs. Small groups have limited access.

Installment payment models spread the therapy cost over multiple years tied to continued clinical response. If the therapy remains effective, the plan pays installments. If it fails, payments stop. The model aligns with the curative logic of one-time therapies replacing years of chronic treatment. The administrative complexity of multi-year installment agreements exceeds what most small group TPAs can manage, and the installment approach creates accounting complications for annually renewing level funded plans.

Why Small Groups Are Unprepared

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Large self-funded employers spread the actuarial variance of low-probability, high-cost events across thousands of members. A 10,000-employee plan can budget conservatively for the statistical possibility of a million-dollar claim without restructuring. A 25-person plan cannot.

The probability that any individual small group plan encounters a cell or gene therapy claim in a given year is low. Hematologic malignancies requiring CAR-T are rare. Sickle cell disease affects approximately 100,000 Americans. Severe hemophilia A affects approximately 20,000. Spinal muscular atrophy is diagnosed in roughly 400 infants per year. The probability is perhaps 1 in 500 to 1 in 1,000 for any given small group in any given year, depending on demographic composition. But a 1 in 500 annual probability, applied across thousands of small group plans in a TPA’s book and measured over a decade of expanding indications, means these claims will occur with statistical certainty.

The demographic profile of the small group level funded market increases certain exposures. Sickle cell disease disproportionately affects Black Americans. Small employers in the South and Southeast, where level funded adoption is growing fastest and Black employment in small business is concentrated, face higher baseline probability of sickle cell gene therapy claims than small employers in other regions. The intersection of disease prevalence and market geography is not theoretical. A TPA with 500 small group clients in the Southeast will encounter a sickle cell gene therapy claim sooner than a TPA with the same number of clients in the Pacific Northwest.

The pipeline expansion accelerates the timeline. Additional CAR-T indications continue to receive FDA approval. Breyanzi gained an accelerated approval for chronic lymphocytic leukemia in March 2024. Kymriah’s indications have expanded to include follicular lymphoma. Gene therapies for additional conditions, including Duchenne muscular dystrophy, retinal dystrophies, and additional hemoglobin disorders, are in late-stage clinical development. IQVIA projects that spending on next-generation biotherapeutics, including cell, gene, and RNA therapies, will reach $18 billion by 2028. Each new approval adds another therapy that can generate a claim exceeding the total annual claims fund of a small group plan.

The structural unpreparedness is the point. Cell and gene therapies are not theoretical future risks. They are current approved therapies. The small group level funded market has not developed standardized risk transfer mechanisms, pricing structures, or administrative frameworks to handle them. The claims arrive anyway.