Clinical Therapeutics: Rituximab Serum Concentrations and Anti-Rituximab Antibodies During B-Cell Depletion Therapy for CFS/ME - Rekeland,Mella et al

[Kalliope]

Rituximab Serum Concentrations and Anti- Rituximab Antibodies During B-Cell Depletion Therapy for Myalgic Encephalopathy/Chronic Fatigue Syndrome
Rekeland, Fluge, Mella et al

(only the abstract is available for now)

Findings
There were no significant differences in mean serum rituximab concentrations between 14 patients experiencing clinical improvement versus 9 patients with no improvement. Female patients had higher mean serum rituximab concentrations than male patients at 3 months (P = 0.05). There was a significant negative correlation between B-cell numbers in peripheral blood at baseline and rituximab serum concentration at 3 months (r = −0.47; P = 0.03). None of the patients had ADAs at any time point.

Implications
Clinical improvement of patients with ME/CFS in the KTS-2-2010 trial was not related to rituximab serum concentrations or ADAs. This finding is also in line with a recent randomized trial questioning the efficacy of rituximab in ME/CFS. Rituximab concentrations and ADAs still offer supplemental information when interpreting the results of these trials.

 

[Trish]

This seems to be part of the process of trying to figure out what factors might have contributed to some patients responding well to Rituximab in the Phase 2 trial and some not responding. It's good to see they are being thorough in exploring this.

 

[Jenny TipsforME]

Yes reassuring because rituximab could have been instantly dropped without understanding the discrepancy between results.

 

[MeSci]

Ah - ADAs are antidrug antibodies.

 

[CFS_for_19_years]

Full text is available now:
http://sci-hub.tw/https://linkinghub.elsevier.com/retrieve/pii/S0149291818305149