Apremilast, a novel PDE4 inhibitor, inhibits spontaneous production of tumour necrosis factor-alpha from human rheumatoid synovial cells and ameliorates experimental arthritis.
BACKGROUND
Type 4 phosphodiesterases (PDE4) play an important role in immune cells through the hydrolysis of the second messenger, cAMP. Inhibition of PDE4 has previously been shown to suppress immune and inflammatory responses, demonstrating PDE4 to be a valid therapeutic target for immune-mediated pathologies. We assessed the anti-inflammatory effects of a novel PDE4 inhibitor, apremilast, in human synovial cells from rheumatoid arthritis (RA) patients, as well as two murine models of arthritis.


METHODS
Cells liberated from tissue excised from arthritic joints of RA patients were cultured in the presence of increasing concentrations of apremilast for 48 hours and spontaneous tumour necrosis factor-alpha (TNFalpha) production was analysed in culture supernatants by ELISA. In addition, arthritis was induced in BALB/c and DBA/1 mice by passive transfer of anti-type II collagen mAb and immunisation with type II collagen, respectively. Mice with established arthritis received 5 or 25 mg/kg apremilast and disease severity was monitored relative to mice receiving vehicle alone. At the end of the study, paws were removed and processed for histopathological assessment. Behavioural effects of apremilast, relative to rolipram, were assessed in naïve DBA/1 mice using an automated activity monitor (LABORAS).


RESULTS
Apremilast dose dependently inhibited spontaneous release of TNFalpha from human rheumatoid synovial membrane cultures. Furthermore, apremilast significantly reduced clinical score in both murine models of arthritis over a ten day treatment period and maintained a healthy joint architecture in a dose-dependent manner. Importantly, unlike rolipram, apremilast demonstrated no adverse behavioural effects in naïve mice.


CONCLUSIONS
Apremilast is an orally available PDE4 inhibitor that reduces TNFalpha production from human synovial cells and significantly suppresses experimental arthritis. Apremilast appears to be a potential new agent for the treatment of rheumatoid arthritis.
The Kennedy Institute of Rheumatology, Imperial College London, 65 Aspenlea Road, London, W6 8LH, UK. f.mccann@ic.ac.uk
Fiona E
FE
McCann
Andrew C
AC
Palfreeman
Melanie
M
Andrews
Dany P
DP
Perocheau
Julia J
JJ
Inglis
Peter
P
Schafer
Marc
M
Feldmann
Richard O
RO
Williams
Fionula M
FM
Brennan
D000818:Animals; D001169:Arthritis, Experimental / Q000188:drug therapy*; D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D002478:Cells, Cultured; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D058988:Phosphodiesterase 4 Inhibitors; D010726:Phosphodiesterase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use; D020889:Rolipram / Q000009:adverse effects / Q000627:therapeutic use; D012720:Severity of Illness Index; D013583:Synovial Membrane / Q000187:drug effects / Q000378:metabolism*; D013792:Thalidomide / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D058988:Phosphodiesterase 4 Inhibitors; D010726:Phosphodiesterase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D013792:Thalidomide; D020889:Rolipram; C505730:apremilast