"The number of PML cases is important because if the infection rate climbs too high, the drug's sales growth may drop. Regulators have said that they watch the cases, but have concluded that the benefits of the medicine to MS patients outweigh the risks.Biogen reports that as of Sept. 30, 2010, there are 55,100 patients using the drug around the world and that approximately 75,500 patients have used the drug since its launch. Of the 75 total cases of PML, 33 cases were in the United States, 38 cases were in the European Union, and 4 cases were in other areas.
The overall global PML rate is about 0.96 per 1,000 patients, a company spokeswoman said, which still falls within the 1-in-1,000 rate previously seen in clinical trials and implied on the drug's label. But the rate has been rising, and multiple Wall Street analysts raised concern about the trend on Wednesday as the MS market is becoming increasingly competitive."
"The most recent data update translates to a rate of 1.49 cases per 1,000 for patients on the drug for a year or longer, but rises to 1.97 per 1,000 for those on the drug for two years or longer.According to these growing numbers, the death rate of Tysabri/PML patients is at 20%. I wish that we knew the condition of the other 80% of PML patients. Unfortunately, I do not know the breakdown of the location of the 15 PML-related deaths.
Looked at another way, the rate is about 1.49 cases per 1,000 patients on the drug for between two and three years. The incidence is about 0.37 case per 1,000 patients in those using it for one to two years, and it is essentially nonexistent in patients using it for less than a year."
Source: Multiple Sclerosis Resource Centre and NASDAQ Copyright (c) 2010 Dow Jones & Company, Inc. (18/11/10)
Edited to Add:
The distribution of PML cases and number of deaths reported by Biogen and/or FDA is as follows:
Month reported; Total # PML cases; # in USA, # in Europe, Other; # Deaths
Nov 2010 - 75 total - 33; 38; 4 - 15 deaths
Oct 2010 - 70 total - 29; 37; 4 - 14 deaths
Sep 2010 - 68 total - 28; 36; 4 - 14 deaths
Aug 2010 - 63 total - 25, 34; 4 - 12 deaths
July 2010 - 58 total - 22; 32; 4 - 12 deaths
June 2010 - 55 total - 20; 32; 3 - 11 deaths
May 2010 - 49 total - 19; 27; 3 - 11 deaths
April 2010 - 46 total - ?; ?; ? - 11 deaths
Mar 2010 - 42 total - 15; 24; 3 - 9 deaths
Feb 2010 - 35 total - 11; 21; 3 - 8 deaths
Jan 2010 - 31 total - 10; 19; 2 - 8 deaths
Nov 2009 - 27 total - ?; ?; ? - 5 deaths
Sep 2009 - 24 total - 8; 16; 0 - 4 deaths
July 2009 - 11 total - 3; 8; 0 - 1 death
Here is the Morning Equity Briefing published on Davy Research website regarding the new PML cases and their impact on Tysabri usage.
Elan Corp (ELN US)
Monthly safety update on Tysabri
Closing Price: $5.55 Rating: Outperform 30/06/09
FACTS: The latest safety update on Tysabri was released last night (November 16th). Five new PML cases were confirmed during October and this brings the total to 75. Four of the cases were in the US, bringing the total there to 33. There have been 38 cases in the EU and four in the rest of the world. Fifteen of the 75 patients (20%) with PML have died.
ANALYSIS: The new cases have increased the overall incidence of PML in those patients exposed to Tysabri to 0.96 per 1,000 from 0.91 per 1,000. Observing the data by treatment epoch, the new cases look to be in patients with at least 25 infusions.
Distribution of PML patients by treatment epoch has stayed broadly consistent for some months now (note that all data are per 1,000 patients exposed). For 1-12 months, the rate remains at 0.01, indicating little or no PML. For 13-24 months, the rate is 0.37 compared to 0.38 previously. For 25-36 months, the incidence rate remains highest at 1.49, up from 1.44. The 37-48 month increased from 0.93 to 1.01 but remains lower than the 25-36 month cohort.
The data also outline, to 95% statistical confidence levels, what the estimated upper and lower bounds may reach for each of the treatment epochs. There is little change in the mix here and it continues to hover close to 2.0 for the longer durations.
DAVY VIEW: We would not expect that this monthly data will materially change physicians' or regulators’ views on Tysabri’s risk/benefit profile, as there looks to be no sharp increase in either the actual PML rate or the statistical upper bounds of incidence.
UPDATE: Biogen announces updated Tysabri/PML statistics. The total number of cases is now at 85 patients with the addition of 6 new cases reported in January 2011. The number of deaths holds at 16 patients. Of the total PML cases, 36 were in the U.S., 44 were in the European Union and five in other areas.