3rd edition another success: Therapeutic Drug Monitoring of Biologics Symposium

On 9th of December, another successful edition of the Therapeutic Drug Monitoring (TDM) of biologics symposium took place

‘The miracle cure’ is how treatment with a biologic was considered when they were first introduced, recalls rheumatologist Gertjan Wolbink from Reade in his opening lecture of the third TDM of Biologics symposium. Almost 25 year after the introduction of the biologic infliximab in Crohn’s disease, biologics are the fastest growing line of treatment in chronic diseases. The next step is now how to personalise these class of drugs. In a fully packed theatre at the Amsterdam public library, pharmacists, pharmacologists, clinicians, scientists and drug developers shared their insights into optimised dosing of these drugs.


A programme of 13 speakers covering personalised dosing of biologics in chronic diseases such as rheumatology, neurology, dermatology, and gastroenterology was offered to the 200 person strong international audience. It was the third time Sanquin, Amsterdam UMC, and Reade joined forces in organising the TDM of Biologics symposium in central Amsterdam. The vibrant atmosphere resulted in excellent debates with speakers and audience during the breaks and panel discussions, leading to new ideas and collaborations. 


Better treatment with biologics by therapeutic drug monitoring

The consensus on the benefit of TDM of biologics to optimise treatment of individual patients is quickly growing. Successful cases were presented of pro-active TDM of infliximab in inflammatory diseases, TDM informed dose interval extension of natalizumab in multiple sclerosis patients, and the value of TDM in inflammatory bowel disease. However, some questions remain open. A blatant example is the therapeutic window, the bloodserum concentration of biologic at which it is neither under- nor overdosed. Despite some therapeutic window being reported for various biologics in clinical guidelines, these are crude targets and may be conservative. More studies are needed to get a more detailed idea of the lower boundary of the therapeutic window. A compounding factor is that most of the research into the therapeutic window is done by (academic) public entities, challenged for funding. Some of the data may already be available from the clinical studies for marketing authorisation, however these are not made publicly available by industry. A general call to industry was made by the attendants to share this data.


Improving access of patients to therapeutic drug monitoring of biologics

Another hot topic during the day was (in)accessibility of TDM to the patient. Currently just a selected group of patients has access to TDM, generally only when their physician has a specific interest in TDM. Several hurdles to wide-spread implementation were discussed. The presentation of the Dutch programme ‘’Health care evaluation and appropriate use’’ (Zorgevaluatie en gepast gebruik) that brings together parties in healthcare (hospital boards, insurance companies, medical specialist organization, patient organisations, etc) with the goal to speed up implementation of health innovations was inspirational and spurred an entertaining discussion. Also, the need to educate more physicians on TDM of biologics and the need for tools to make interpretation of results easier were identified. International networks that set out to conduct these tasks, such as ENOTTA and the society of, mainly, hospital pharmacists IATDMCT, presented themselves and attracted new members in the process.


Future of therapeutic drug monitoring of biologics

In line with the growing number of biologics, TDM of biologics is bound to flourish. Several trends in this regard were shared by the presenters. For starters, the immune response against the biologic (immunogenicity) is increasingly a challenge in drug development. Whereas in daily clinical practice immunogenicity against the newer biologics has limited impact. Second, new biologics tend to be dosed higher. This poses a challenge to finding the lower boundary of the therapeutic window as generally only high blood concentration (in the plateau of the concentration-response curve) are found. On the other hand, it creates more opportunity for TDM informed dose interval extension. Finally, the value of TDM outside the established chronic disease setting, in this case oncology, was fiercely debated where there was a clear need for further research on precisely this therapeutic window.


All in all the day ended well before the conversations were tuning down. The ground works are already being laid down for the next edition of the TDM of biologics symposium series. And do join the IATDMCT in Oslo in September 2023!