Bio-similars or Bio-differents? What we can learn from real world data?

For this reason the question of equivalence cannot be reduced to a formal confirmation of biosimilarity. For protein hormones, whose action depends on receptor binding and on pharmacokinetics, even small differences in isoform composition could in theory be reflected in the ovarian response. The lecture helps the practising clinician grasp why similar and identical are not synonyms, and where the boundary lies between the regulatory concept of a biosimilar and clinical reality.

The central part is devoted to comparing two types of evidence. Randomized controlled trials remain the gold standard, yet they are conducted in tightly selected populations and under strict protocols, which limits the transfer of conclusions to the heterogeneous flow of real patients. Real-world data, by contrast, reflect everyday conditions — the full spectrum of ages, ovarian reserve and concomitant factors — and reveal how a product behaves outside the idealized frame of a clinical trial.

The speaker shows that these two sources of evidence do not compete but complement each other. A randomized trial answers whether a product works under controlled conditions; real-world data answer whether that result is reproduced in an ordinary clinic. Discrepancies between them do not necessarily signal an error: they point to factors that a formal study may have failed to capture and provide grounds for closer analysis.

Separate attention is given to the reasons why accumulated observations are able to change everyday practice. When real-world data consistently point to differences in efficacy, tolerability or the predictability of response, the clinician has grounds to reconsider a habitual choice of product — not on the basis of a single case, but on the basis of a reproducible trend.

The practical takeaway of the lecture is that the choice of a gonadotropin deserves a critical approach that draws on the whole available body of evidence. The clinician is encouraged not to treat biosimilarity as a guarantee of full interchangeability, but to weigh a product's regulatory status against the real-world data of their own and other clinics, making the decision deliberately and in the interest of the individual patient.