Not so fast with fasinumab celebrations


Anyone thinking that rehabilitation of the anti-nerve growth factor MAbs was complete with an apparent phase III win for Teva and Regeneron’s fasinumab should be more cautious. True, the study, in patients with chronic pain from osteoarthritis of the knee or hip, met its co-primary efficacy endpoints at 16 weeks. But it was merely a sub-study of a one-year safety trial, the results of which will be key as the anti-NGFs have been linked with rapidly progressing osteoarthritis (RPOA). The signs so far are hard to read: at 24 weeks fasinumab was linked with a 2% placebo-adjusted increase in RPOA, but the companies did not give absolute rates; in any case, this looks higher than the less than 1.5% RPOA incidence recently seen with Pfizer and Lilly’s tanezumab in phase III. Also, Teva and Regeneron were unclear on whether any fasinumab patients had experienced type 2 RPOA, the more severe form – only saying that “the majority” of arthropathies were of the less serious type. Pfizer and Lilly did not give this information with tanezumab either, and also did not disclose any efficacy data. Perhaps all will become clearer when full results emerge at upcoming meetings.

Fasinumab 16-week phase III data 
Endpoint Placebo Fasinumab 1mg every 8 weeks   Fasinumab 1mg every 4 weeks Fasinumab 3mg every 4 weeks  Fasinumab 6mg every 8 weeks
Change in  WOMAC pain score -1.56 -2.25  (p=0.0019) -2.78 (p=0.0001)  Discontinued for safety reasons
Change in WOMAC physical function score -1.37 -2.10 (p=0.0011)  -2.57 (p=0.0001) Discontinued for safety reasons
Source: company press release.

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