5 Costly Mistakes Self-Funded Employers Make With Their Drug Benefit Plans (And How to Fix Them)

Mistake 1: Blindly Trusting Your PBM Without Auditing Claims or Verifying Transparency

The majority of self-funded plan sponsors delegate their entire pharmacy benefit operation to a Pharmacy Benefit Manager (PBM). The relationship is usually established under the assumption that the PBM is a neutral cost-saving fiduciary, leveraging its scale to secure steep manufacturer discounts and pass-through rebates. In reality, the traditional PBM business model is structurally designed to maximize intermediary profits at the expense of the employer's plan.

The most prevalent mechanism of profit extraction is spread pricing. Under a spread pricing model, when an employee fills a prescription at a network pharmacy, the PBM reimburses the pharmacy a low rate (e.g., $15 for a generic cholesterol drug) but charges the employer’s plan a significantly higher rate (e.g., $110 for that same transaction). The difference—the "spread"—is retained by the PBM as pure profit. Because these spreads are shielded behind strict non-disclosures, employers have no way of knowing how much they are overpaying for generic commodities.

Furthermore, many traditional contracts feature vague wording regarding "allowable administrative fees," "rebate retention," and "reclassification of drug types," which allow the PBM to pocket rebates that should legally flow back to the plan sponsor. The PBM may classify a high-cost specialty drug as something other than a "specialty" drug on paper, avoiding the contractual rebate guarantees altogether.

The Real Cost of Opacity

Forensic benefits audits demonstrate that spread pricing and unpassed rebates inflate an employer’s generic drug costs by 15% to 30%. For a mid-market employer with 1,000 covered lives, un-audited claims and opaque contract terms routinely result in $150,000 to $300,000 in annual leakage. Additionally, without independent claims audits, billing errors (such as duplicate refills, invalid days’ supply, and incorrect copay tiering) go entirely undetected, representing another 2% to 4% of total pharmacy spend.

The Fix: Actionable Steps for Plan Sponsors

• Mandate a "Pass-Through, Fiduciary" Contract: Transition your plan to a transparent, 100% pass-through PBM contract. Ensure the contract legally defines the PBM as a fiduciary to your plan, outlaws spread pricing completely, and mandates that 100% of all manufacturer rebates, discounts, and administrative fees are returned directly to the plan sponsor.
• Enact "Anytime Audit" Rights: Traditional PBM contracts restrict your ability to audit claims, often limiting audits to once per year, using an auditor handpicked by the PBM, or restricting the sample size to 100 claims. Draft contract terms that grant your plan unrestricted access to raw de-identified claims data and allow independent third-party auditors of your choosing to audit 100% of claims at any time.
• Audit Generic Pricing via MAC (Maximum Allowable Cost) Transparency: Require the PBM to provide daily or weekly updates to their MAC list (the state-specific pricing index for generic drugs). This prevents the PBM from delaying the price-drops of generics as ingredients become cheaper in the market.

Mistake 2: Ignoring Specialty Drug Spend — Letting 2% of Claimants Drive 50%+ of Costs

For many years, benefits managers focused their attention on generic dispensing rates. While maintaining high generic utilization is a valuable baseline, it does nothing to address the nuclear threat on an employer's balance sheet: specialty medications. These are complex, highly managed therapies—frequently biologics, oncology drugs, or orphan medications—used to treat conditions like rheumatoid arthritis, multiple sclerosis, and cancer.

Because these medications represent clinically critical therapies for vulnerable staff members, HR directors are highly hesitant to touch specialty drug plans, fearing employee disruption, regulatory backlash, or legal exposure. PBMs capitalize on this hesitation, implementing generic or automated prior authorization processes that wave high-cost claims through with minimal clinical justification.

When specialty drug reviews are left to the PBM's internal automated system, approval rates are artificially high. Why? Because the PBM routinely earns a percentage-based fee on specialty drug volume or retains a massive rebate on brand-name specialty products. They have zero incentive to deny an unnecessary drug or steer the patient to a clinically identical, lower-cost alternative.

The Real Cost of Specialty Neglect

The statistics are clean and alarming: specialty medications account for less than 2% of total prescription volume but drive 50% to 55% of total pharmacy spend. The average annual cost for a single specialty patient exceeds $84,000. Under an unmanaged specialty plan, a single patient on an ultra-orphan drug (such as Soliris, Carvykti, or gene therapies) can generate $350,000 to $2.5 million in annual claims. Such claims easily breach stop-loss thresholds, triggering substantial renewals and crushing the self-funded plan’s cash reserves.

The Fix: Actionable Steps for Plan Sponsors

• Carve Out Prior Authorizations to an Independent Third Party: Remove prior authorization (PA) decision-making power from the PBM. Contract with an independent, clinically neutral third-party clinical reviewing firm. Independent reviewers have no financial stake in the dispensing of the drug and will rigorously audit every specialty script against strict, evidence-based clinical protocols before approving it.
• Deploy a Sophisticated Specialty Copay Maximizer Program: Many high-cost specialty drugs have manufacturer copay cards that cover the patient’s out-of-pocket costs (up to $20,000 annually). Work with an expert consultant to implement a copay maximizer program. This structures your plan so that the manufacturer's program covers the vast majority of the drug’s cost, lowering the plan's net exposure from thousands of dollars to near-zero for that drug while keeping patient out-of-pocket costs at zero.
• Establish Dynamic Specialty Sourcing Channels: For ultra-high-cost specialty medications, explore alternative sourcing programs, including highly regulated direct-sourcing models or specialty clinically integrated community pharmacy partnerships that bypass highly inflated PBM specialty pharmacies.

Mistake 3: Not Leveraging Biosimilars or Therapeutic Alternatives to Reduce Spend

We are currently living through the most significant patent cliff in pharmaceutical history. Highly expensive biologic drugs (which are derived from living cells rather than chemically synthesized) are finally facing competition from biosimilars—highly accurate, clinically identical FDA-approved equivalents that act like "generics" for biologics.

Despite the availability of these lower-cost equivalents, many self-funded plans are still paying top dollar for original brand-name biologics. This occurs because of the notorious "Rebate Trap." Because PBMs negotiate brand rebates on multi-billion dollar biological drugs (like Humira, Enbrel, or Stelara), they purposefully structure their formularies to exclude the lower-cost biosimilars.

The PBM blocks the cheaper alternative because the brand-name manufacturer pays the PBM a massive rebate for maintaining exclusive "preferred" status. Although the gross price of the brand-name drug is highly inflated, and the employer is technically getting back a rebate check at the end of the year, the "net cost" of the brand drug is still far higher than the net cost of the un-rebated biosimilar.

The Real Cost of the Rebate Trap

Consider brand Humira (adalimumab), which can cost a plan up to $7,000 per patient per month. In 2023 and 2024, multiple FDA-approved Humira biosimilars hit the U.S. market. For example, Blue Shield of California bypassed traditional PBM directories and acquired a clinically identical biosimilar for $525 per month—a 75% savings. Yet, traditional PBM plans routinely steer patients away from these biosimilars. If you have just five employees on Humira under an unmanaged plan, you are overpaying by upwards of $300,000 annually compared to a plan that enforces biosimilar substitution.

The Fix: Actionable Steps for Plan Sponsors

• Adopt an Active "Biosimilar-First" Formulary: Mandate biosimilar substitution across all therapeutic classes where FDA-approved biosimilars are available. Instruct your consultant to build a "custom formulary" that places original high-cost clinical brands in an excluded or non-preferred tier unless a medical necessity exemption is clinically proven.
• Conduct a Net-Cost Formulary Alignment Audit: Hire an independent consultant to analyze your top-20 high-cost brands and compare their total plan net cost (gross cost minus rebates) against available therapeutic alternatives and biosimilars. If the un-rebated alternative represents a lower overall net cost to the plan, transition the preferred status on the formulary immediately.
• Educate and Transition Claimants: Partner with clinical advisors to proactively contact physicians and patients who are currently using brand biologics. Provide them with standard clinical materials demonstrating the therapeutic equivalence of the biosimilar and transition them seamlessly.

Mistake 4: Failing to Implement a GLP-1 Management Strategy as Demand Skyrockets

There has never been a class of drugs that has captured the cultural and consumer consciousness quite like GLP-1 receptor agonists (principally Ozempic, Mounjaro, Wegovy, and Zepbound). Originally developed to treat Type 2 diabetes, these medications have proven to be exceptionally effective at inducing weight loss by regulating metabolic pathways and appetite.

The resulting consumer demand is unprecedented. HR directors are caught in a pincer movement: employees are demanding full coverage for these medications, claiming they are core to competitive talent retention and overall wellness. On the other hand, CFOs are staring in horror at the monthly pharmacy invoices.

Most employers have implemented binary policies: they either completely exclude weight-loss drugs from their plan (which drives massive employee dissatisfaction and leads to "off-label" prescribing of diabetes-indicated GLP-1s like Ozempic for weight loss) or they cover them completely with no clinical guards, allowing anyone with a telehealth script to access a $1,000-a-month drug indefinitely.

The Real Cost of Unmanaged GLP-1s

GLP-1 medications carry retail or contract list prices ranging from $900 to $1,450 per patient per month. With over 42% of the U.S. adult population meeting the clinical criteria for obesity, an unmanaged plan coverage policy is financially crippling. If just 5% of a 500-employee workforce gets prescribed a GLP-1 for weight loss, the plan faces $300,000 in direct annual liabilities. This single drug class is currently driving 15% to 25% budget increases for self-funded plans nationwide.

The Fix: Actionable Steps for Plan Sponsors

• Establish Clinical Metabolic Step Therapy: Do not authorize premium GLP-1 therapies as first-line weight-loss interventions unless less expensive wellness and lifestyle modifications are proven. Require patients to document a 3-to-6 month trial of active participation in an structured metabolic, nutritional, and physical exercise program before authorizing a GLP-1.
• Implement Strict Clinical Efficacy Reviews: Do not issue indefinite approvals for GLP-1 weight-loss medications. Limit initial authorizations to 12 or 16 weeks. Require the patient’s physician to document a minimum of 5% to 7% body weight loss within that period to qualify for a re-authorization. If the drug is not producing measurable, therapeutic weight loss, authorization must be discontinued.
• Enact Rigorous Off-Label Guardrails: Audit your Type 2 diabetes list to ensure that diabetes-indicated GLP-1s (Ozempic and Mounjaro) are only approved and dispensed to patients with a lab-confirmed diagnosis of Type 2 diabetes (indicated by a hemoglobin A1C of 6.5% or higher). This stops "diagnosis code gaming" where doctors write a diabetes code for a weight-loss patient to bypass plan exclusions.

Mistake 5: Treating the Pharmacy Benefit as Separate From the Medical Benefit

In most corporate HR departments, the medical benefit and the pharmacy benefit are treated as two entirely distinct silos. The medical benefit is administered by a third-party administrator (TPA) or corporate carrier, while the pharmacy benefit is managed by a separate PBM. These two platforms utilize entirely different claiming systems, database architectures, and taxonomy rules.

This division creates a massive structural gap: the clinic-administered drug blind spot. Many high-cost specialty drugs, especially those administered via intravenous infusion or injection in a clinical setting (such as Remicade, Keytruda, or Ocrevus), are processed as medical claims (using medical billing codes, known as "J-codes") rather than pharmacy claims.

Because the medical benefit is processed by a TPA that specializes in hospital billing, medical drug claims are rarely audited for pharmacy-level pricing. Hospital outpatient centers take advantage of this gap by purchasing these specialty medications at low prices and marking them up by hundreds of percent before billing the employer’s medical plan.

The Real Cost of Siloed Benefits

Up to 30% of total specialty drug spend occurs under the medical benefit, completely hidden from the PBM's formulary controls. Hospital outpatient departments charge plan sponsors 3x to 5x the average sales price (ASP) for oncologist-administered and autoimmune infusions. For example, a single dose of Remicade that costs $1,500 to buy can be billed to an employer's medical benefit for $7,500 to $12,000 per infusion. By ignoring medical drug claims, employers leak hundreds of thousands of dollars on clinic markups that are fully preventable.

The Fix: Actionable Steps for Plan Sponsors

• Build a Unified Medical-Pharmacy Cross-Benefit Audit: Contract with a specialized benefits diagnostic partner to integrate your medical and pharmacy data. This allows you to track all specialty drug claims holistically, regardless of whether they have been submitted via a pharmacy card or billed under a medical J-code.
• Implement a "Site of Care" Optimization Program: Structure your plan design to incentivize patients to receive infusions at independent, specialized infusion clinics, doctor's offices, or through highly trained home infusion networks instead of hospital outpatient settings. Infusion costs at independent clinics are historically 50% to 70% cheaper than hospital settings, with equal or superior clinical safety records.
• Utilizing "Buy-and-Bill" Alternatives: Require your TPA to direct-source medical pharmaceuticals via specialty distribution channels (like a specialty pharmacy carve-out) or apply maximum allowable medical payment rates (ASP + 6%) on medical drug claims, putting a firm cap on hospital markup margins.

Conclusion: Pharmacy Benefit Strategy as a Boardroom Advantage

For years, self-funded employers tolerated rising key drug costs as an inevitable tax on doing business. The system was deemed too complex to untangle, too clinical to alter, and too personal to question. In today's hyper-competitive macroeconomic climate, this passivity is a luxury employers can no longer afford.

The employers who build a sustained competitive advantage in the decade ahead will be those who treat healthcare not as a fixed corporate overhead cost, but as an actively managed strategic asset. Reclaiming control of your pharmacy benefit plan does not mean cutting benefits, reducing coverage, or forcing sicker employees to suffer. On the contrary, every single step outlined here improves the clinical validity of the care delivered while aligning pricing structure with actual market value.

A proactive pharmacy benefit strategy—anchored in absolute transparency, clinical independence, and modern benefit alignment—converts waste directly back into operating margins. For a business operating on a 10% margin, saving $200,000 in unmanaged pharmacy leakage has the same balance sheet impact as generating $2,000,000 in new sales revenue. It is time for HR directors, CFOs, and benefit executives to step into the supply chain, shine a light on the opaque middlemen, and build a health benefit plan that serves their employees and protects their organization's financial future.