We are maintaining our 2-Equal Weight rating on BIIB following this month's update on Tysabri
from jim birchenoff of Barclays formerly lehman
PML incidence. With 4 new cases of PML this month, with an accelerating rate and with a rate now >1/1000 in patients treated >12 months we see risk to increasing drug holidays, further reduction in new patient starts and further label restrictions if rates in patients >2 years continue to increase.
BIIB & partner Elan provided an update Thursday on PML incidence for Tysabri through April 6. With 4 new cases over the last month and 46 new cases overall incidence of PML has increased in all treatment duration categories. Specifically PML incidence is now 0.67/1000 overall, 1.10/1000 in patients with more than 12 infusions, 1.27/1000 in patients with more than 18 infusions, 1.59/1000 in patients with more than 24 infusions and 1.53/1000 in patients with more than 30 infusions.
While the increasing rate with increasing duration is well-acknowledged and has been reflected in updated Tysabri labelling we believe that the acceleration of cases into April could create still greater tentativeness in prescribing with greater impetus for earlier drug holidays in a greater percent of patients.
Read more:
Biogen Idec: PML Accelerating into April »
