NBRx vs NRx vs New Patient Starts: Which New Patient Number Your Specialty Brand Should Trust

Three new patient numbers, each answering a different question

Ask a specialty brand how many new patients it added last month and the answer depends on who is in the room. Brand quotes new prescriptions (NRx) or new-to-brand prescriptions (NBRx) from syndicated data. Patient services quotes referrals or enrollments from the hub. The specialty pharmacy team quotes first fills shipped. Each number can be calculated correctly and still disagree with the others, sometimes in opposite directions in the same month.

The three measure different things. NRx counts prescriptions with a new prescription number, which includes a doctor rewriting a script for a patient already on therapy, for example after a dose change or when the old prescription runs out of refills. NBRx counts prescriptions for patients who had no fill of the brand within a lookback window, so it includes patients new to the market, patients switching from another product, add-ons and patients restarting after a long gap. A new patient start, built from specialty pharmacy dispense data, counts the first time a patient actually received drug. Only the last one says a patient began therapy.

For a retail brand the gap between these numbers is often small enough to ignore. For a specialty brand dispensed through a limited network of specialty pharmacies, with prior authorization, bridge supply and long time to therapy, the gap can be large and it moves forecasts, incentive pay and launch decisions. This article explains each measure, where they part ways and the rules that make one new patient number hold up. It builds on our guides to defining an active patient and launch analytics.

Where the numbers part ways in specialty

• A new script is not a new patient

  Dose changes, new strengths and rewritten prescriptions all create a new prescription number. NRx rises while the number of people on therapy stays the same.

  • Titration counted as new demand
  • Refill limits create new scripts
  • Pharmacy transfers can look new

• The lookback decides who is new

  NBRx treats a patient as new to brand if there was no fill inside the lookback window. Change the window and restarts move in or out of the count.

  • Restarts read as new patients
  • Lookback rarely shown on the slide
  • Different windows across vendors

• Coverage is not complete

  Syndicated prescription data depends on which pharmacies report to the data provider. In a limited distribution network, one pharmacy not reporting can change the trend.

  • Projected volumes, not counted ones
  • Network changes shift the trend
  • Free drug fills usually absent

• A referral is not a start

  Hub referrals and enrollments count intent. Patients lost to benefits verification, prior authorization denials or cost never start, and some patients start without passing through the hub.

  • Abandoned referrals counted
  • Direct-to-pharmacy starts missed
  • Bridge shipments counted as paid starts

What a new patient number that holds up looks like

How to put it in place

Questions leaders ask about NBRx, NRx and new patient starts