An important highlight of ECTRIMS this year was the data on the safety of the anti-CD20 therapies as a class. It is clear that prolonged, and sustained, B-cell depletion is not safe. Hypogammaglobulinaemia will become a problem with the risk of both common and opportunistic infections.
Stephen Hauser presented the 7-year ocrelizumab safety data and there is a clear uptick in infections in year 7. His poster also included a probable opportunistic infection signal. As of January 2019, there were six potential serious opportunistic infections that had been reported from the ocrelizumab clinical trials.
- Systemic Pasteurella infection in a patient with RMS following a cat bite (resolved)
- Multisegmental herpes zoster infection in a patient with RMS, treated with intravenous (IV) acyclovir (resolved)
- Enterovirus-induced fulminant hepatitis in a diabetic patient with RMS, resulting in liver transplant
- Candida sepsis in a patient with PPMS who had stopped OCR treatment 11 months previously and was receiving cancer chemotherapy (resolved)
- Viral meningitis in a patient with RMS, cerebrospinal fluid positive for varicella-zoster, treated with IV acyclovir (resolved)
- Herpes zoster (monodermatomal) in a patient with RMS treated for a neutropenic fever (not assessed as an opportunistic infection) (resolved)
Continuous anti-CD20 therapy prevents you from forming germinal centres (where B-cells get educated and selected to make antibodies) in lymph nodes and the spleen. In other words, the anti-CD20 therapies result in what I refer to as a functional splenectomy. This causes a scotoma, or blind spot, in your immune system which means you can’t mount a vigorous immune response to new infectious agents or vaccines. In reality, your immune responses are muted.
I highlighted in my hot topics talk on ‘DMTs in RRMS 2019: what remains to be achieved’ about the problems of having a functional splenectomy on anti-CD20 therapies. I recommended that all MSers be vaccinated with the polyvalent pneumococcal vaccine (Pneumovax) and possibly the vaccines for Haemophilus influenzae type B and Meningococcus. In addition, all MSers should have the annual flu vaccine, but with the inactivated component flu vaccine and not the live flu vaccine. In fact, MSers on anti-CD20 therapy should avoid coming into contact with recipients of the live flu vaccine in case it becomes more virulent and infects them. Please note the live flu vaccine is used in the UK in young children and it is recommended that children who have parents or family members at home on immunosuppressive therapies should not have this vaccine.
Another option open to people on longterm anti-CD20 therapy is antibiotic prophylaxis against infections with these encapsulated bacteria. I suspect this may be necessary when MSers develop hypogammaglobulinaemia and recurrent infections, similar to the NMO cases described below. It is clear that anti-CD20 therapies will need annual immunoglobulin levels measured so that if hypogammaglobulinaemia develops MSers can we warned. I suspect immunoglobulin replacement therapy will only be required in the case of recurrent infections, for example, sinus or chest infections; for example, the NMO patient on longterm rituximab who developed bronchiectasis.
I would also recommend that MSers on immunosuppressive therapies wear a medic-alert bracelet that states they are on an anti-CD20 therapy. This would help HCP in an emergency if you are too sick to provide a history. An American colleague told me about one of his ocrelizumab-treated patients, who was fit and well, who died suddenly in the emergency department after presenting with a high temperature and not feeling well. I suspect the cause of death was probably septic shock from one of the encapsulated bacteria discussed above.
The facts that (1) the clinical development programme of ocrelizumab was stopped in rheumatoid arthritis and lupus because of infections and excessive number of deaths, (2) that there is a herpes zoster signal on ocrelizumab, (3) there is blunted vaccine response, in particular to pneumococcus, and (4) ocrelizumab reduces immunoglobulin levels explains why there are infectious complications on ocrelizumab.
So if you are on rituximab, ocrelizumab, ofatumumab or any othe anti-CD20 please be vigilant and take care. On the other side of the coin are the benefits of these treatments and their ease of use and low monitoring burden. As with all DMTs the risks need to be balanced against the benefits.
Tallantyre et al. Secondary Antibody Deficiency and infection following B-cell depletion for CNS neuroinflammation. ECTRIMS Online Library. Oct 25, 2017; 199742; EP1722
B-cell depleting anti-CD20 monoclonal antibody therapies have demonstrated promising clinical efficacy in suppressing relapses in individuals with neuromyelitis optica (NMO) and multiple sclerosis (MS). However, uncertainties remain about the optimum treatment schedule. In rheumatological disease, anti-CD20 agents are most often employed for short-term induction therapy and are subsequently replaced by longer-term maintenance therapy. In contrast, repeated cycles of anti-CD20 monoclonal antibody therapy are proposed as maintenance therapy for CNS neuro-inflammatory disorders. Post-marketing surveillance will be essential to fully uncover the long-term safety profile of repeated B-cell depletion. Hypogammaglobulinaemia is a recognised consequence in a proportion of patients treated with medium- to long-term B-cell therapy and may play a role in the increased incidence of infection observed in the anti-CD20 arms of treatment trials. We report 5 cases of serious infection associated with hypogammaglobulinaemia occurring in patients receiving rituximab for NMO. The cases were all female, all had low IgG with variable reductions in IgM and IgA. The cases had a mean treatment duration of 3.1 years, but not all cases had had extensive exposure (treatment duration range 0.5 – 6.2y). We review the evidence relating to hypogammaglobulinaemia following anti-CD20 treatment for neuroinflammatory disorders and propose an algorithm for monitoring and treatment of this recognised complication.