- In patients with metastatic melanoma treated with ipilimumab, low serum levels of ipilimumab and development of antidrug antibodies (ADAs) are associated with reduced survival.
Why this matters
- Little is currently known about the clinical effects of ADA development.
- Low serum levels of ipilimumab before the second infusion (n=24) were associated with reduced OS (HR, 1.3 per 1 μg/mL; P=.01) and PFS (HR, 1.2 per 1 μg/mL; P=.02).
- Low serum levels of ipilimumab before the fourth infusion (n=20) were not significantly associated with OS or PFS (data not shown).
- 26% of patients were ADA-positive at the second or fourth infusion.
- ADA positivity was associated with reduced OS (HR, 3.0; P=.03).
- 50% of ADA-positive patients vs 13% of ADA-negative patients discontinued therapy before the fourth infusion due to disease progression.
- ADA positivity and lower serum levels of ipilimumab were not significantly associated (data not shown).
- 31 patients with ipilimumab-treated metastatic melanoma were analyzed for drug serum levels, and ADAs to ipilimumab at baseline and the second and fourth infusions.
- 77% received 4 infusions.
- Primary endpoints were OS and PFS.
- Funding: None disclosed.
- Small patient sample size.
- Retrospective design.