Generic Substitution Rate (GSR) and Employer-Sponsored Prescription Drug Costs
Generic Substitution Rate (GSR) and employer-sponsored prescription drug costs go together like peanut butter and jelly or Glory green beans and meatloaf. If you’ve never tried Glory green beans pick up a couple of cans during your next trip to the supermarket. You will ditch Green Giant or Del Monte and never go back. Thank me later. It is clear that every pharmacy benefit manager offers clinical services. These clinical services include but are not limited to formulary management and drug utilization management. Drug utilization management includes services such as prior authorization, step therapy, quantity limits, therapeutic substitution, dose optimization, refill to soon, and a host of others. What isn’t so clear is how does a self-insured employer or broker measure the performance of clinical services? Generic Substitution Rate (GSR) is the best metric for measuring PBM clinical management performance. Clinical services are popular among purchasers of PBM services, yet their effectiveness remains a mystery to many. Let’s first review the Big Three for drug utilization management programs before diving into GSR and its significance. The Big Three includes prior authorization, quantity limits and step therapy services. Prior Authorization (PA). Requires approval by the PBM or plan administrator before payment to the pharmacy is permitted. The drugs which require prior authorization or PA are high cost, have the potential for abuse or waste, or require monitoring to reduce the risk for dangerous side effects. Quantity Limits (QL). A maximum quantity of drugs that can be dispensed to a patient at one time. The primary purpose of quantity limits is to reduce wasteful spending in the case a 90-day supply isn’t necessary, for instance. All specialty drugs should have a 30-day or less supply quantity limit. Step Therapy (ST). Costly drugs are dispensed only when the patient has tried a less costly drug. For example, a lower cost specialty or non-specialty drug would be required before the more costly specialty drug is approved by the PBM or plan administrator. Some benefit designs may require failure on two or more drugs in a step therapy process before the costliest drug is approved. I’m occasionally asked by brokers and plan administrators, “should we be tracking our Generic Substitution Rate?” My answer is always the same, an emphatic yes! Generic Dispense Rate (GDR) and Generic Substitution Rate are major contributors to PMPM plan cost. In fact, GDR and GSR are congruent. Because they work in harmony, high performance with GDR means the same for GSR and vice versa. GDR and GSR as major contributors to final plan costs is an understatement. Figure 1. Generic Dispense Rate (GDR) Table Figure 1 is the actual Generic Dispense Rate (GDR) performance from one of our clients. Generic Dispense Rate (GDR) is the percentage of all prescription drug fills that were for generics. For April, this client’s GDR was 93.5%. For every 1% increase in GDR a plan can expect to realize a 2.5% reduction in gross drug spend. Going from an 80% to 90% GDR means a…