Prescription drug benefits used to be a routine part of employer health insurance: pay a copay, get the medication. Then specialty drugs happened. Cancer biologics, autoimmune treatments, gene therapies, and GLP-1s for diabetes and weight management have shifted the math entirely. The average specialty prescription now costs more than $5,000 per fill, and a single high-cost member can drive five percent of an entire small-employer plan's annual spend. The drug benefit is no longer a routine cost line; it's a strategic decision affecting plan design, employee out-of-pocket costs, and overall health benefit affordability.
How Formulary Tiers and Cost Sharing Work Most plans use a four-tier formulary. Tier 1 is generic drugs, with the lowest copay (often $5 to $15). Tier 2 is preferred brand-name drugs, with a moderate copay or coinsurance (typically $30 to $60 or 20 to 30 percent). Tier 3 is non-preferred brand-name drugs, with higher cost sharing. Tier 4 is specialty drugs, often subject to coinsurance of 20 to 40 percent and high deductibles.
The tier assignment is set by the plan, with input from the pharmacy benefit manager. A drug's tier placement affects member cost dramatically. The same medication can cost an employee $10 in one plan and $400 in another based purely on tier assignment and coinsurance structure.
The Role of Pharmacy Benefit Managers Pharmacy benefit managers (PBMs) sit between health plans, drug manufacturers, and pharmacies. They negotiate drug prices and rebates with manufacturers, maintain the formulary, run the prior authorization and step therapy programs, and operate mail-order and specialty pharmacies. Three PBMs (CVS Caremark, Express Scripts, OptumRx) control roughly 80 percent of the US prescription drug market.
The PBM business model has come under sustained scrutiny. The FTC released its second interim staff report on PBM practices in 2025, focused on rebates and the impact of vertical integration. Federal and state legislation continues to address PBM transparency, with several states requiring rebate disclosure to plan sponsors and prohibiting certain spread-pricing practices. Employers should ask their PBM for full pass-through pricing and detailed rebate transparency as part of any contract negotiation.
What Are Prior Authorization and Step Therapy? Prior authorization requires the prescribing physician to get approval from the PBM before a specific medication is covered. Step therapy requires the patient to try lower-cost alternatives first before stepping up to a more expensive option. Both are cost-control mechanisms; both also create friction for patients and providers, and both have generated regulatory pushback. Several states have passed laws limiting PBM use of step therapy for chronic conditions where the patient has previously stabilized on a specific medication.
Specialty Drugs and Why They're Reshaping Drug Benefits Specialty drugs are typically biologic medications used to treat complex chronic or rare conditions: cancer, multiple sclerosis, rheumatoid arthritis, hemophilia, and similar. They often require special handling, refrigeration, and clinical support. Specialty drugs now account for roughly 50 percent of total drug spend despite being prescribed to a small percentage of plan members.
The growth of GLP-1 medications (semaglutide, tirzepatide) for diabetes and weight management has accelerated the cost pressure. Plans are responding with prior authorization, step therapy, and in some cases excluding GLP-1 coverage for weight management entirely. Each design choice has tradeoffs between cost control and member access.
Designing Prescription Drug Benefits That Actually Work For benefits leaders, the core levers are formulary design, cost sharing, PBM contract terms, and clinical management programs. The right combination depends on the workforce: a younger workforce with low chronic disease prevalence has different needs than an older population with multiple specialty conditions.
Three practices distinguish well-managed prescription drug benefits programs. First, real PBM transparency: pass-through pricing, full rebate disclosure, and detailed claims data access. Second, member-friendly cost sharing: avoiding deductibles on essential medications and using copays rather than coinsurance for tier 1 and tier 2 drugs. Third, integration with broader benefits: pairing the drug benefit with disease management programs, telehealth, and employee health navigation. The Centers for Medicare and Medicaid Services publishes prescription drug benefit research at cms.gov , and the Bureau of Labor Statistics tracks employer prescription drug benefit prevalence at bls.gov/ebs . Pair drug benefit design with broader health insurance choices like a PPO or HDHP plan to ensure the overall coverage picture is internally consistent.
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