The biological drugs have all been successfully used to treat
rheumatoid arthritis (RA) and have led to fair rates of clinical remission; however, the possible occurrence of adverse events such as
infectious diseases or
cancers means that the patients undergoing treatment need to be closely monitored. Anti-TNF agents, first appeared in the pharmacological algorithm of RA in the early 2000s, seem to lead to a higher risk of reactivated tubercular
infection than the biological agents with different mechanism of action (
abatacept or
rituximab). Although the data on anti-TNF agents and
cancer are controversial, their use is currently not recommended in neoplastic patients because of their uncertain effects on immune-surveillance. The safety profile of
abatacept is similar to that of other biological agents, while
rituximab is used to treat non-Hodgkin
lymphomas and is also considered in the case of RA patients with previous hematological or non-
hematological malignancies. The risk of
infections and new-onset
cancers during
tocilizumab treatment is similar to that associated with other
biological therapies. Finally, under particular circumstances, such as in the presence of
infections or
malignancies, blocking a specific immunological pathway may be simultaneously successful and detrimental. The only thing that can be done at the moment is to continue to look for adverse events in order to discover these complications as soon as possible, and then develop the most appropriate means of treating (and even preventing) them.