CTLA 4 Success Rate melanoma trials.. Jim Breitfeller

The most interesting data was on ipiliumumab (abstract #9033), which looked at the effect of the agent on 18 and 24 month survival from 3 phase II trials dosed at 10mg/kg every 3 weeks (plus maintenance therapy Q12W from week 24 in appropriate patients) in advanced melanoma, where survival outcomes are usually poor. Ipilumumab is a fully humanised monoclonal antibody that targets T-lymphocyte antigen 4 (CTLA-4).

The 3 studies summarised were CA184-008, CA184-022, CA184-007.

The results clearly showed that:

- 12 month survival rates were >47%
- 18 month survival rates were >34%
- 24 month survival rates were >30%

"For previously treated patients, 24 month survival rates ranged from 24% to 33%.
Long term survivors included patients with progressive disease according to WHO criteria.
These results are promising but caution must be extended because a significant number of patients were lost to follow-up, which may reduce the reliability of the results. Ongoing biomarker studies are looking at predicting which patients are most likely to benefit from ipilumumab therapy.

Ipiliumumab


What did we learn from these trials? Well, there is an urgent need to define optimal endpoints for melanoma clinical trials in terms of response rate, PFS, OS and survival at 12 months. It is interesting that over the past 10 years the majority of abstracts have hyped the results in this disease as 'promising' or 'clinically active' regimens and yet very little in the way of new therapies have actually been approved by the FDA. Based on these data, I suspect it will still be a little while before we see some solid phase III data in malignant melanoma."









Take Care,

Jimmy B