Substitution between brands of biological medicines is considered by the Pharmaceutical Benefits Advisory Committee (PBAC) and recommended on a case-by-case basis.
The current practice of ‘a’ flagging in the Schedule of Pharmaceutical Benefits denotes that brand substitution may be undertaken by pharmacists at the point of dispensing without differences in clinical effect.
‘a’ flagging is a well-established mechanism that is well understood by physicians and pharmacists
- The PBAC is an independent expert committee appointed by the Australian Government. Members include eminent, highly qualified and experienced physicians, health professionals, health economists and consumer representatives. Its decisions are based on evidence about clinical effectiveness, safety and cost-effectiveness.
- A recent study shows that the “no brand substitution” box is ticked on only a very small number of prescriptions – 1% of computer-generated prescriptions and 0.7% of handwritten prescriptions. [Ref Newby DA, Robertson J. Computerised prescribing: assessing the impact on prescription repeats and on generic substitution of some commonly used antibiotics. MJA 2010; 192: 192-195].
- Pharmacists are required by law to follow the instructions of the prescribing physician on a prescription. Under section 103 of the National Health Act 1953 it is illegal for substitution to occur when the script is marked “no brand substitution permitted”. The offence carries a penalty of $2000 or imprisonment for 12 months, or both.
- The PSA Guidelines for Pharmacists on PBS Brand Substitution state clearly that brand substitution may only occur after consultation with and agreement of the patient (or the carer), and if the prescriber has not indicated on the prescription, “no substitution”, or equivalent. Pharmacists are also directed specifically to be consistent in the selection of brands for patients on long-term therapy, in order to avoid confusion.
A PBAC recommendation for ‘a’ flagging should be made where supporting evidence exists
- Substitution is recommended by the PBAC only after the TGA has determined that a medicine is comparable to the reference medicine. Both determinations are reliant on government authorities evaluating a comprehensive portfolio of data and providing a recommendation on whether the biosimilar is similar enough to the originator biologic.
- Current reporting has not identified a different rate or type of adverse event (AE) being reported for biosimilars.
- GBMA supports robust and adequate pharmacovigilance for all medicinal products based on their individual risk profile, regardless of whether the product is a reference or a follow-on product, a chemical molecule or a biologic. Due to the special characteristics of biologics (certain variability due to batch-to-batch variation or manufacturing changes), it is especially important for biologics that adverse event reporting does not solely rely on the International Non-proprietary Name (INN), but also uses available differentiators like brand name, company name, and batch number.
- Biosimilars should be required to adhere to appropriate risk management plans comparable to those required for other biologics in the same class. There is no rationale to hold them to a higher standard.