Your PBM RFP Will Only Be as Good as the Questions You Ask

Last spring, a client’s CFO called in a panic. Their pharmacy benefit manager had sent a renewal with a “guaranteed” rebate number that sounded impressive: $155 per member per year. The plan spent $1.3 million annually for 900 employees, and the CFO asked, was this a good deal? Or just a shiny number? As always, it started with the questions we were (and weren’t) asking in the RFP itself.

Launching a PBM RFP isn’t a formality. The right questions will pull back the curtain on pricing games, network exclusions, and formulary tricks. The wrong ones mean you’ll compare marketing promises, not real-world impact. In 2024, you can’t just ask for “discount guarantees” and call it a day. You’ll want to drill down on network definitions (are those “in-network” pharmacies actually convenient for your workforce?), specialty drug pricing (are Humira biosimilars included, and how are they classified?), and the method for calculating rebates (is it paid on all claims or just on preferred brand drugs?).

Start with these core RFP questions:

• How are discounts and rebates calculated, AWP minus what percent, and is AWP defined per Medispan or First Databank?
• Which drugs and claims are included/excluded from guarantees (specialty, mail, 340B, copay assistance)?
• How are specialty drugs defined (which NDCs, which pharmacies)?
• Is there a guaranteed minimum rebate per script, or just an aggregate average?
• What is the mail-order penetration and home delivery uptake in similar employer groups?
• Which clinical programs are included in the base pricing (prior auth, step therapy, utilization management)?
• Can we audit 100% of claims data? Is it in a machine-readable format per CMS Transparency rules?

Digging deep here makes “apples to apples” possible later. You’d be surprised how many proposals dodge the details, especially on how “specialty” and “rebate eligible” are defined.

Guarantees You Can Actually Hold a PBM To

Not all guarantees are created equal. The big three PBMs, CVS Caremark, Express Scripts (Cigna), OptumRx, are masters at promoting big rebate and discount numbers, only to carve out high-cost drugs from those guarantees. Meanwhile, newer entrants like Capital Rx or Navitus often provide more clarity, but may have less negotiating power with massive specialty blocks.

If you’re a 600-employee, $1.2 million annual pharmacy plan, these are the guarantees you need, in writing, with definitions that survive a year-end audit:

• Brand and generic discount guarantees, expressed as AWP minus XX% for retail, mail, and specialty, and tied to a clear drug list (NDC-level).
• Rebate guarantees, minimum per script on all brand drugs, paid on all utilization, with clear language around exclusions (no silent carve-outs for Humira or “specialty lite” drugs).
• Specialty drug pricing and definition, which drugs are classified as “specialty,” and are biosimilars included? For example, if your Humira patients move to Hadlima or Cyltezo, are those paid at the same rate?
• Audit rights and penalties, can your finance team or an outside consultant audit 100% of claims, and will the PBM pay make-whole penalties if they miss?

There’s no such thing as too much specificity. If the PBM promises “guaranteed rebates,” but carves out the 15 most expensive specialty drugs (including those monoclonal antibodies or GLP-1 agonists like Ozempic and Mounjaro), you’re not comparing real guarantees. Ask to see the contract exhibit, not just a marketing summary.

How to Compare PBM Proposals When Nothing Matches Up

This is where most RFP processes fall apart. One PBM quotes rebates on 85% of scripts, another on 100%. One quotes AWP minus 50% on specialty at CVS, but your plan only fills 10% of specialty at retail. The result? “Savings” that disappear once the plan goes live.

To overcome this, use a disruption analysis and a standardized claims repricing. Pull two years of your actual raw claims (all NDCs, all channels), and require each finalist to reprice them file-for-file with their contract terms and definitions. If your data house or PBM consultant can’t handle this, find one who can. RxPBM.ai and other benchmarking tools can help standardize the side-by-side.

Next, evaluate clinical program differences. For instance, a carved-in program with “automatic prior auth” for GLP-1 weight loss drugs might look less restrictive, but will drive higher spend, $900/month per Ozempic or Wegovy user, with 5% of your adult population seeking scripts. Meanwhile, a plan that excludes or tightly manages GLP-1s could save $250,000/year for a 900-life group, but creates member complaints. You’ll need to weigh those trade-offs.

Look beyond the PMPM and rebate numbers. Compare:

• Real net cost per member per month after all admin fees, rebates, and clinical program costs (benchmark: $100-$140 PMPM in 2024)
• Specialty share of spend (typically 50-55% in employer groups)
• Projected impact of biosimilar adoption, e.g., switching 20 Humira patients to a biosimilar saves roughly $340,000/year for a 900-life employer
• Mail-order and 90-day fill penetration (target: at least 20% for maintenance meds if mail is favored and accessible)

If you can’t get “apples to apples,” document which apples are actually oranges, and why. Flag those for leadership before making a recommendation.

What a Successful PBM RFP Looked Like for a 900-Life Manufacturer

Last year, a Midwest manufacturer ran a PBM RFP after seeing costs spike 19% on a $1.3 million pharmacy budget. They started with a messy spreadsheet: three PBM proposals, each touting different rebate guarantees and specialty definitions. Our team demanded full claims repricing and lined up questions as described above.

Express Scripts quoted $145 PMPY rebate guarantees, but after reviewing the contract language, Humira and all biosimilars were excluded. Meanwhile, Navitus offered lower raw rebates, $108 PMPY, but included all specialty claims, and allowed 100% of claims audits with make-whole penalties. When the claims repricing came back, Navitus delivered a $124 PMPM net cost (vs $139 for Express Scripts), with biosimilar flexibility and tighter clinical management of GLP-1s.

The client selected Navitus, not because the spreadsheet “guarantee” was highest, but because the real-world numbers held up and contract terms aligned with their workforce. Over six months, trend flattened, specialty migration started, and HR had leverage for the next contract cycle. The lesson: the right questions and contract detail made more difference than the headline numbers.

One Step Every Employer Should Take This Quarter

Whether you’re about to issue an RFP, or staring at a renewal, pull a full raw claims file for the past 12-24 months. If you can’t get it, escalate to your PBM, no comparisons are credible without it. Then, demand that every PBM bidder or incumbent use that file, NDC by NDC, to show contract terms in action. Only then will your RFP process steer you to real savings and fewer unwelcome surprises for your employees and leadership team.