Primary central nervous system lymphoma: time for diagnostic biomarkers and biotherapies?

PURPOSE OF REVIEW: Primary central nervous system lymphoma (PCNSL) is a rare cancer with a somber prognosis in older patients, which it affects predominantly. Only in recent years have molecular alterations characterizing PCNSL been thoroughly described. This opens possibilities for the use of targeted therapies. Developments in imaging and biomarkers have also great potential to help clinicians faced with diagnostic and prognostic uncertainties. RECENT FINDINGS: Several biomarkers for PCNSL, such as different microRNAs, which could be tested in cerebrospinal fluid and vitreous fluid, and IL-10, which has been shown to have excellent sensitivity and specificity in the cerebrospinal fluid, have emerged in the last years. Methotrexate-based regimens remain the gold standard first-line treatment, with recent studies looking at the best adjunctive molecules to methotrexate, including rituximab, and at the role of autologous stem cell transplantation. As mutations leading to the activation of nuclear factor-kappa-B signaling are found in most PCNSLs, with mutations of MYD88 and CD79B particularly, ibrutinib is studied as molecule of great interest and encouraging results have been found in pilot studies. There is also great interest in the immunomodulatory drugs (lenalidomide) and immunotherapy (anti-programmed cell death 1/programmed cell death 1 ligand 1). SUMMARY: Identification of molecular genetic and cytokine changes in tumor and liquid biopsies will have an increasing role in the diagnostic and follow-up of PCNSL but also in the treatment and management of the disease.

Methotrexate and temozolomide versus methotrexate, procarbazine, vincristine, and cytarabine for primary CNS lymphoma in an elderly population: an intergroup ANOCEF-GOELAMS randomised phase 2 trial.

BACKGROUND: No standard chemotherapy regimen exists for primary CNS lymphoma, reflecting an absence of randomised studies. We prospectively tested two promising methotrexate-based regimens, one more intensive and a milder regimen, for primary CNS lymphoma in the elderly population, who account for most patients. METHODS: In this open-label, randomised phase 2 trial, done in 13 French institutions, we enrolled immunocompetent patients who had neuroimaging and histologically confirmed newly diagnosed primary CNS lymphoma, were aged 60 years and older, and had a Karnofsky performance scale score of 40 or more. Participants were stratified by Karnofsky performance scale score (<60 vs ≥60) and treating institution and randomly assigned (1:1) to receive methotrexate (3·5 g/m(2)) with temozolomide (150 mg/m(2)) or methotrexate (3·5 g/m(2)), procarbazine (100 mg/m(2)), vincristine (1·4 mg/m(2)), and cytarabine (3 mg/m(2)). Neither regimen included radiotherapy; both included prophylactic G-CSF and corticosteroids. The primary endpoint was 1-year progression-free survival. Analysis was intent to treat, in a non-comparative phase 2 trial design. This study is registered with ClinicalTrials.gov, number NCT00503594. FINDINGS: Between July 16, 2007, and March 25, 2010, 98 patients were enrolled, of whom 95 were randomly assigned and analysed; 48 to methotrexate with temozolomide and 47 to methotrexate, procarbazine, vincristine, and cytarabine. 1-year progression-free survival was 36% (95% CI 22-50) in the methotrexate, procarbazine, vincristine, and cytarabine group and 36% (22-50) in the methotrexate with temozolomide group; median progression-free survival was 9·5 months (95% CI 5·3-13·8) versus 6·1 months (3·8-11·9), respectively. Objective responses were noted in 82% (95% CI 68-92) of patients in the methotrexate, procarbazine, vincristine, and cytarabine group versus 71% (55-84) of patients in the methotrexate with temozolomide group. Median overall survival was 31 months (95% CI 12·2-35·8) in the methotrexate, procarbazine, vincristine, and cytarabine group and 14 months (8·1-28·4) in the methotrexate with temozolomide group. No differences were noted in toxic effects between the two groups. The most common grades 3 and 4 toxicities in both groups were liver dysfunction (21 [4%] in the the methotrexate and temozolomide group and 18 [38%] in the methotrexate, procarbazine, vincristine, and cytarabine group), lymphopenia (14 [29%] and 14 [30%]), and infection (six [13%] and seven [15%]). To date, 33 (69%) patients in the methotrexate and temozolomide group have died, versus 31 (55%) in the methotrexate, procarbazine, vincristine and cytarabine group. Quality-of-life evaluation (QLQ-C30 and BN20) showed improvements in most domains (p=0·01-0·0001) compared with baseline in both groups. Prospective neuropsychological testing showed no evidence of late neurotoxicity. INTERPRETATION: In this study of two different methotrexate-based combination regimens in elderly patients, the efficacy endpoints tended to favour the methotrexate, procarbazine, vincristine, and cytarabine group. Both regimens were associated with similar, moderate toxicity, but quality of life improved with time, suggesting pursuing treatment in these poor prognosis patients is worthwhile. New alternatives are needed to improve response duration in this population. FUNDING: Schering-Plough/Merck and French Government.