Ann: Mesoblast Phase 3 CLBP Trial Completes Enrollment, page-152

The way I read it the lack of need for any other intervention was used as one of the measures of success. The following is taken from the evaluation notes of the Phase 2 results;

• Reduced need for additional surgical and non-surgical interventions: MPC-treated patients had a significantly reduced need for additional interventions at the treated disc level, including surgical intervention (spinal fusion, discectomy or artificial disc replacement) or injection (epidural steroid injection, rhizotomy or transforaminal injections), than saline controls. By 12 months, 25% of patients in the saline control group had undergone an additional intervention, compared with 15% of patients in the HA control group, 6.9% of patients in the MPC-06-ID group and only 3.3% of patients who received 6 or 18 million MPCs. By Kaplan-Meier analysis of time to a first additional treatment intervention, treatment with either MPC-06-ID or 18 million MPC significantly reduced the need for additional interventions compared with saline treatment (p=0.024 and p=0.010, respectively).