0000950123-11-015543 Sample Contracts

Exhibit B LOCK-UP LETTER AGREEMENT

Lock-Up Letter Agreement • February 18th, 2011 • MPM BioVentures IV QP LP • Pharmaceutical preparations

• Contract Type
  Lock-Up Letter Agreement
• Filed
  February 18th, 2011
• Company
  MPM BioVentures IV QP LP
• Industry
  Pharmaceutical preparations

BARCLAYS CAPITAL INC. PIPER JAFFRAY & CO. As Representatives of the several Underwriters named in Schedule I of the Underwriting Agreement, c/o Barclays Capital Inc. 745 Seventh Avenue New York, New York 10019