For many patients living with the painful disease of multiple sclerosis (MS), Tysabri has been a lifeline in reducing symptoms and progression. However, after its patent expired in 2015, a biosimilar drug, Tyruko, entered the market. Biosimilar drugs are pharmaceuticals with the exact mechanism and active ingredient (Natalizumab—a monoclonal antibody targeting T cells) as the pre-patented product, with a beneficial slash off the price (on average 72% cheaper). What’s not to love?
Ordinarily, extensive tests are performed to assess biosimilar drugs. According to MS society, results show that Tysabri and Tyruko had no difference in ability to decrease relapse frequency, reduce lesions, slow down progression, and pertinently, there was no significant difference in reported side effects.
Despite these promising conclusions, the stories began at Charring Cross Hospital, London, where approximately 170 out of 345 MS patients reported side effects. These side effects range from fatigue, relapses, motility issues, and hospitalisation, according to The Guardian. Rumours circled around of a potential 15 other hospitals with the same trend in adverse reactions.
Amongst its controversy within patient communities, experts also appear to have differing views on the situation. Dr Andrew Hill, a pharmacology research fellow at Liverpool University, states the importance of investigating "why these side effects are seen and whether they resolve for people who switch back to the branded formulation". Meanwhile, Multiple Sclerosis Trust suggests that the blame rests on the cruel nature of the progressive disease as patients’ MS may be more challenging to manage, and new symptoms may be a common element of their diagnosis, and only a handful of people have been affected.