Cancer clinicians reassured on biosimilar equivalence and switching

Clinicians  managing cancer patients can have confidence in the equivalence of biosimilar products to the original reference molecule when it comes to efficacy, safety and when switching between products, a new Australian consensus statement advises.

With the emergence of biosimilar brands for biologic agents used in haematological cancer such as rituximab, clinicians and patients need to be informed and confident about their place in practice, according to an independent expert panel of haematologists, oncologists and pharmacists.

Led by Dr Gareth Gregory of Monash Haematology, the expert group of clinicians from across Australia has released a series of 10 consensus recommendations developed after  a series of meetings to review literature and discuss issues that may arise in real world clinical practice.

The expert group noted that clinicians will already be familiar with biosimilars  such as filgrastim and epoeitin used in supportive care of blood cancers, but there are now disease-modifying biosimilars being launched such as rituximab brands for treatment of cancers such as B-cell non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukaemia, as well as PBS reimbursement for all CD20 positive B-cell lymphoid cancers, including acute lymphoblastic leukaemia.

But as more biosimilars are introduced in oncology they said there is a need to address concerns that have ben raised “including a lack of confidence that biosimilars will provide equivalent therapeutic outcomes for patients, use in indications that have been approved based on extrapolation of clinical data for the reference medicine, as well as perceptions of risk in ‘switching’ of patients already receiving one brand of a biologic medicine to a biosimilar brand.”

Overall, the expert group concluded that “biosimilar medicines can be considered therapeutically equivalent to their reference brand and used in a similar way to the reference product in any approved indication.”

The ten recommendations are:

  1. A biosimilar medicine approved by the TGA can be considered therapeutically equivalent to its reference product, with equivalent clinical outcomes.
  2. Extrapolated indications: equivalent therapeutic outcomes can be expected from an approved biosimilar regardless of indication (eg a biosimilar rituximab for the treatment of DLBCL).
  3. Similar outcomes including immunogenicity can be expected in a patient who is switched from the reference product to a biosimilar or between biosimilar brands.
  4. Biosimilars and reference products should not be used interchangeably in clinical trials.
  5. Adverse events:  a patient is likely to experience the same reaction with a biosimilar if they had an adverse event with a reference molecule, and so should not be switched. However a biosimilar brand could be used if a re-challenge is necessary.
  6. Doses should remain the same for biosimilars and concomitant  medications.
  7. Patients should be made aware that they are using a biosimilar and its nonproprietary name.
  8. Clear protocols for labelling, switching and tracking are needed if a hospital stocks multiple brands of a biologic medicine. Hospitals also need to nominate their  “default” brand of a medicine.
  9. If limited choices of agent are likely, clinicians need to have a say on which brand of biologic their patient receives.
  10. Biosimilar usage need to be traceable down to individual patient level for pharmacovigilance.

The consensus statement is published in the Asia-Pacific Journal of Clinical Oncology.

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