Specific KIR-HLA genotypes predict outcomes in refractory or relapsed primary central nervous system lymphoma

An effective salvage regimen for the reinduction of remission is lacking for refractory or relapsed primary central nervous system lymphoma (r/r PCNSL). This study aimed to evaluate the efficacy and safety of cytarabine plus temozolomide in treating r/r PCNSL and to explore the associated prognostic factors.

A single-center retrospective cohort study was conducted to assess the efficacy and safety of cytarabine and temozolomide (AT) in r/r PCNSL patients. KIR and HLA genotyping was performed on peripheral blood samples.

Thirty PCNSL patients receiving an AT regimen (cytarabine 3 g/m² for 2 days combined with temozolomide 150 mg/m² for 5 days) in our institution were analyzed. The median age was 65 years (range 25-79 years). A total of 43.4% of patients (13/30) achieved an overall response within a median follow-up of 16 months (95% confidence interval [CI]: 11-23 months). The median PFS and OS of the cohort were 1.5 months (95% CI: 1-4 months) and 19.5 months (95% CI: 11 months to not calculable), respectively. Patients harboring KIR3DL1/HLA-B genotypes predicting low affinity had a higher response rate (p = 0.042) and longer median PFS (3 months) than those with KIR3DL1/HLA-B genotypes predicting high affinity (1 month) (p = 0.0047). Cox regression analysis indicated that KIR/HLA-B genotypes were independently associated with PFS (p = 0.043). However, KIR/HLA-B genotypes had no impact on the OS of the cohort. The toxicity of AT treatment was mild and manageable.

The AT regimen was well tolerated, and patients with specific KIR-HLA genotypes may benefit from this regimen.