Would you consider re-challenging a patient with rituximab after they experienced delayed neutropenia?

This is an important question as rituximab is a key treatment option across multiple rheumatic conditions. Probably the best study to inform this question comes from Zonozi et al., PMID 32892495 who retrospectively studied 738 RTX-treated patients at a single institution. They found that late-onset neutropenia (LON) occurred in 6.6% of patients and was much more common in the first year of treatment. Notably many patients also received cyclophosphamide and combination therapy with cyclophosphamide was associated with an increased risk of LON. 60% were asymptomatic. Notably, they rechallenged 87% of patients with RTX of whom 21% of patients developed recurrent LON.

What do I take away from this study (which is in line with other case series o...

3% of patients treated with Rituxan may have delayed neutropenia. I would not re-challenge them with Rituxan and would consider giving the Neupogen to raise the patient's WBC count if it was too low.