Natalizumab and progressive multifocal leukoencephalopathy: what are the causal factors and can it be avoided?
Natalizumab (Tysabri) was the first monoclonal antibody approved for the treatment of relapsing forms of multiple sclerosis (MS). After its initial approval, 3 patients undergoing natalizumab therapy in combination with other immunoregulatory and immunosuppressive agents were diagnosed with progressive multifocal leukoencephalopathy (PML). The agent was later reapproved and its use restricted to monotherapy in patients with relapsing forms of MS. Since reapproval in 2006, additional cases of PML were reported in patients with MS receiving natalizumab monotherapy. Thus, there is currently no convincing evidence that natalizumab-associated PML is restricted to combination therapy with other disease-modifying or immunosuppressive agents. In addition, recent data indicate that risk of PML might increase beyond 24 months of treatment.
Warnke
Clemens
C
Neurology Section, VA North Texas Health Care System, Medical Service, 4500 S Lancaster Rd, Dallas, TX 75216, USA.
Menge
Til
T
Hartung
Hans-Peter
HP
Racke
Michael K
MK
Cravens
Petra D
PD
Bennett
Jeffrey L
JL
Frohman
Elliot M
EM
Greenberg
Benjamin M
BM
Zamvil
Scott S
SS
Gold
Ralf
R
Hemmer
Bernhard
B
Kieseier
Bernd C
BC
Stüve
Olaf
O
D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D039041:Integrin alpha4beta1 / Q000276:immunology; D007968:Leukoencephalopathy, Progressive Multifocal / Q000188:drug therapy* / Q000276:immunology*; D000069442:Natalizumab
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D039041:Integrin alpha4beta1; D000069442:Natalizumab