To provide open-label re-treatment with PROCHYMAL to participants enrolled in companion Protocol 603 to evaluate the safety in participants with active Crohn's disease who are resistant to standard Crohn's disease therapies.

Participants will receive infusions of PROCHYMAL on Day 42, Day 84, and Day 126 after initial infusion of PROCHYMAL in Protocol 603. Each infusion will contain 200 million cells. As participants will be required to be in Protocol 603 during the entire duration of their participation in Protocol 611, all concomitant medication and safety information will be monitored by Protocol 603 and the combination of data from the two protocols.

Inclusion Criteria:

• Participant must have qualified for, enrolled in, and provided written informed consent form (ICF) and authorization for use and disclosure of protected health information (PHI) for Protocol 603 after the August 3, 2010.
• Participant successfully completed all screening assessments in Protocol 603 as required by Protocol 603.
• Participant successfully completed the full course of each of the four infusions of investigational agent on Days 0, 3, 7, and 14 of Protocol 603 after August 3, 2010.
• Participant must enroll in Protocol 611 on or before the 45th day after first infusion in Protocol 603.
• Participant must provide written ICF and authorization for use and disclosure of PHI for Protocol 611.

Exclusion Criteria:

• Participant is unwilling or unable to adhere to requirements of Protocol 611.
• Participant had confirmed respiratory distress during a PROCHYMAL infusion in any prior PROCHYMAL study.
• Participant had a serious adverse event in any previous PROCHYMAL study that was deemed by the principal investigator of that study to be possibly or probably related to PROCHYMAL and also that was within 48 h after a PROCHYMAL infusion.