Aims
Three phase I/II studies conducted at NCI demonstrated 5-yr survival rates of 13-25%. Evaluation of the long-term survival benefit of IPI for MM pts from 3 additional completed phase II studies continues. Here we report 5-yr survival data.

Methods
Trials included: (1) CA184-008, a single-arm study of IPI at 10 mg/kg in pretreated pts; (2) CA184-022, a dose-ranging study of IPI at 0.3, 3, or 10 mg/kg in pretreated pts with crossover from lower doses to 10 mg/kg allowed upon disease progression; and (3) CA184-007, a study of IPI at 10 mg/kg +/- prophylactic budesonide in treatment-naive and pretreated pts. IPI was given q 3 wks x 4 (induction); eligible pts could receive reinduction or maintenance IPI q 12 wks from Week 24. The analysis reports OS with updated last known alive date or death based on data collected through March 2012. Safety data for these trials have been previously published.

Results
Survival rates at 5 yrs appeared similar to those at 4 yrs and ranged from 12-28% in pretreated pts and 38-50% in treatment-naive pts. In trial 008, median OS was 10.2 m. In trial 022, median OS was 8.6 m, 8.7 m and 11.4 m for IPI at 0.3 mg/kg, 3 mg/kg and 10 mg/kg, respectively. In trial 007, median OS in the IPI + placebo arm was 30.5 m and 14.8 m for treatment-naive pts and pretreated pts, respectively, and 45.0 m and 8.5 m for treatment-naive and pretreated pts, respectively in the IPI + budesonide arm.

Conclusions
Across studies, 5 yr OS rates appear similar to those at 4 years, suggesting that IPI monotherapy may result in prolonged survival in some pts with MM. Further research and analyses are needed to identify the pt population with MM most likely to achieve long term survival benefit from IPI therapy.