BSPGHAN 2021 Virtual Annual Meeting

27- 29 April 2021

EFFICACY OF THIOPURINES IN PREVENTING INFLIXIMAB ANTIBODY FORMATION WHEN USED IN DUAL THERAPY: EXPERIENCE FROM A SINGLE TERTIARY PAEDIATRIC GASTROENTEROLOGY DEPARTMENT

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Christine Spray
Christine Spray
3 months ago

Thank you for your poster. This is a common question. Please can the author confirm the dose of azathioprine used. Do the authors aim for a specific level of 6 TGN and is this possible? Did increasing the dose of azathioprine reduce IFX AB? Although those patients who required intensification were excluded, would it be interesting to analyse these patient for IFX antibodies and 6-TGN levels ?

Azim Muhamad Amin
Azim Muhamad Amin
3 months ago

Thank you for your time to read the poster and for the questions Dr. Spray.

1) The dose of azathioprine used is 2mg/kg (increased to 2.5mg/kg if necessary).
2) We used level between 235-450 pmol6TGN/8×10^8 red cells: maximum drug efficacy in IBD, however, we appreciate in practice it can be quite tricky.
3) We have not explored the relationship between Azathioprine dose increment in this study however that could potentially an area to be discussed for future studies.
4) For those patients that required intensification, it would definitely be interesting to see if they would still have the same relationship with patients who did not need intensification ie lower ADA formation.

Let us know if you have any further queries.

Last edited 3 months ago by Azim Muhamad Amin
David Campbell
David Campbell
3 months ago

Thank you. I think your first figure suggests there is no significant difference in frequency of anti IFX antibodies with 6TG levels (p=0.91)?
The second graph suggests a possible polynomial distribution or perhaps an inflexion after 300pmol of 6TG? In either case the data suggests a proportional (but not directly proportional) association between IFX ab levels and plasma 6TG concentrations.
Your data suggests a contrary conclusion to the one you have made?