Exhibit 10.19

ADDENDUM No. 5 TO LEASE

This is an Addendum to the Lease dated June 1, 1993 in which BioTime, Inc., a
California corporation, is referred to as “Lessee.” The following changes are
hereby incorporated. In the event of a conflict of terms, those of this ADDENDUM
shall prevail.

1.   Regarding Paragraph 1: The term shall be extended an additional one
(1) year commencing April 1, 2004 and terminating March 31, 2005.   2.   The
Base Rent shall remain $11,696 per month for the lease term.

           Lessee and Lessor shall each have the right to terminate the Lease at
anytime by giving the other written notice no less than Ninety (90) days in
advance.

     
  /s/ Judith Segall
  March 12, 2004

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for BioTime, Inc., Lessee
  Date

       
Its
  Vice President- Operations  

 

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  Member, Office of the President  

     

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for BioTime, Inc., Lessee
  Date

             
Its
 

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  /s/ Donn Logan
  March 12, 2004

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Donn Logan, Lessor
  Date
 
   
  /s/ Marcy Li Wong
  March 12, 2004

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Marcy Li Wong, Lessor
  Date