Palo Alto-based StemCells filed a second lawsuit last week in a California federal court against Neuralstem alleging infringement of two patents related to human neural stem cells, reported the Associated Press. 

StemCells issued a press release following the filing of its complaint, which described the nature of its suit as follows:

The California action alleges that Neuralstem and its two founders infringed the Company’s U.S. Patent No. 7,115,418 (methods of proliferating human neural stem cells) and its recently issued U.S. Patent Number 7,361,505 (neural stem cell compositions of matter).  The two patents had not previously been asserted by StemCells against Neuralstem and are not part of the pending Maryland litigation initiated by StemCells in 2006, which is currently on hold by court order.   Further, the California action alleges that Neuralstem has engaged in a campaign of misinformation about StemCells’ patents and proceedings before the U.S. Patent Office.  StemCells is seeking compensatory and enhanced damages as well as injunctive relief.  

According to the Associated Press, StemCells previously filed another lawsuit against Neuralstem alleging infringement of two different patents, and Neuralstem just last week filed suit against StemCells in the same Maryland court seeking to invalidate one of the StemCells patents and alleging that StemCells committed fraud and misconduct in gaining that patent.  The Maryland case is currently on hold pending reexamination of the patents.

It goes without saying that the parties appear headed for a long and heated patent battle.  The California Biotech Law Blog will keep you posted on the legal developments as the suit  progresses.