Salvage therapy with temozolomide in an immunocompetent patient with primary brain lymphoma

Consolidation Therapy in Primary Central Nervous System Lymphoma

OPINION STATEMENT

Primary central nervous system lymphoma is a complex disease with no agreed-upon standard-of-care therapy. Induction therapy involves multiagent chemotherapy based on high-dose methotrexate, with several regimens available. We have a preference for a regimen using rituximab, methotrexate (3.5 g/m2), procarbazine, and vincristine (R-MPV) for initial induction therapy, given the favorable balance between toxicities and very high response rates (80-90%), which allow for decreasing disease burden and increasing the effectiveness of consolidation treatments. However, in the absence of consolidation therapies, R-MPV is not an effective regimen to achieve long-term remission.Based on high rates of long-term remission, our first choice for consolidation therapy is high-dose chemotherapy with autologous stem-cell transplant using thiotepa, busulfan, and cyclophosphamide as a myeloablative regimen, with a curative intent. This typically applies to patients with a favorable performance status at the end of induction, typically with ECOG performance status of 2 or better, adequate organ function, and age younger than 70. Patients with a high transplant-related mortality risk may still be considered for milder myeloablative regimens such as carmustine/thiotepa.For patients who are not transplant candidates, we typically offer consolidation with reduced dose whole-brain radiation therapy (WBRT) (23.4 Gy), which seems to be associated with lower risks of neurotoxicity as compared with higher doses of radiation. For patients who are not transplant candidates and that do not accept the risk of cognitive decline from the radiotherapy, we typically offer consolidation high-dose cytarabine, provided the patient understands the high risk of relapse. For these patients, a clinical trial is strongly recommended.

miR-370 Sensitizes TMZ Response Dependent of MGMT Status in Primary Central Nervous System Lymphoma

Primary central nervous system lymphoma (PCNSL) is an aggressive and rare subtype of non-Hodgkin lymphoma, arising exclusively in the CNS with a poor prognosis. Previous evidence has proved that MGMT was a promising target involving in TMZ resistance of PCNSL. Our study described a new miR-370-mediated mechanism of MGMT regulation in PCNSL. We first showed that miR-370 was downregulated in PCNSL tissues, while MGMT was inversely overexpressed. It was also observed that miR-370 suppressed the expression of MGMT. Additionally, upregulation of miR-370 significantly increased TMZ sensitivity dependent of MGMT, thus suppressed Raji cell proliferation and induced apoptosis in vitro. In conclusion, these results suggest that miR-370 is a potential target in PCNSL treatment.

Management of primary central nervous system lymphoma

A rare tumor, primary central nervous system lymphoma can affect immunocompetent and immunocompromised patients. While sensitive to radiotherapy or chemotherapy crossing the blood-brain barrier, it often recurs. Modern treatment consists of high-dose methotrexate-based induction chemotherapy, often followed by consolidation with either radiotherapy or further chemotherapy. Neurotoxicity is however a concern with radiotherapy, especially for patients older than 60 years. The benefit of the addition of rituximab to chemotherapy is unclear. Targeted therapies and immunotherapy have been effective in some patients and are tested on a larger scale. Survival has improved in the last decade, but remains poor in older patients.

Characteristics and Outcomes of Primary Central Nervous System Lymphoma: A Retrospective Study of 91 Cases in a Chinese Population

BACKGROUND

Primary central nervous system lymphoma (PCNSL) is a rare disease affecting the brain, leptomeninges, spinal cord, cerebrospinal fluid, or vitreoretinal compartment, without evidence of systemic disease. Prognosis is still poor after intensive methotrexate-based chemotherapy.

METHODS

Clinical data of 91 patients treated in a tertiary referral center during a 13-year period were retrospectively reviewed.

RESULTS

The estimated median progression-free survival and overall survival (OS) for the entire cohort were 39.1 months (95% confidence interval [CI], 14.1-64.0 months) and 54.5 months (95% CI, 28.9-80.1 months), respectively. Estimated 5-year progression-free survival and OS were 37.0% ± 6.5% and 47.5% ± 7.5%. Survival was associated with cycles of methotrexate only in multivariate analysis. Seventy-four patients received methotrexate-based chemotherapy after diagnosis. Thirty-nine patients experienced disease progression. Patients with relapsed/refractory disease had a poor survival, with median second OS (calculated from the date of first disease progression to the time of death from any cause) being 7.2 months (95% CI, 2.5-12.00 months). Three patients responded to ibrutinib after disease progression and incurred no fungal infection.

CONCLUSIONS

The outcomes of patients with PCNSL treated in our cohort are still poor. Relapse or refractory PCNSL and those not tolerating aggressive chemotherapy urgently require new approaches to improve their still dismal prognosis. Novel agents such as ibrutinib have shown promising clinical activity. Future studies should focus on the predictive biomarkers for the treatment of PCNSL with novel agents to provide precision medicine for PCNSL.

Primary central nervous system lymphoma: Retrospective analysis of 34 cases in a single centre

Objective

To retrospectively analyse outcomes in patients with primary central nervous system lymphoma (PCNSL), which is a malignant CNS non-Hodgkin’s lymphoma with a poor prognosis.

Methods

This study retrospectively analysed the treatment and outcomes of patients with PCNSL, which were divided into two groups: surgery (S) group and surgery/biopsy+chemotherapy (SC) group. The latter group was further subdivided into four cohorts based on the treatment regimen: cyclophosphamide, epidoxorubicin, vincristine and prednisone (CHOP), high-dose methotrexate (HDM)+dexamethasone+rituximab (HDM+D+R), HDM+D+temozolomide (HDM+D+T), and HDM+D+R+T.

Results

The study enrolled 34 patients; 10 of which received surgery only. Between the S and SC groups, the median progression-free survival (PFS) and overall survival (OS) of intracranial PCNSLs (n = 32) were 8.5 months versus 29 months, respectively; and 8.5 months versus 54 months, respectively (5-year OS: 10.0% versus 48.7%, respectively; 2-year PFS: 0.0% versus 52.6%, respectively). Comparing the CHOP and HDM-based chemotherapy cohorts, the median PFS and OS were 15 months versus not achieved, respectively, and 25 months versus not achieved, respectively (5-year OS: 20.0% versus 60.8%, respectively; 2-year PFS: 20.0% versus 62.7%, respectively).

Conclusion

Chemotherapy appears to provide a better OS and PFS for patients with PCNSLs compared with surgery alone. HDM+D+T and HDM+D+R+T may be effective choices for PCNSL treatment.

The Challenge of Primary Central Nervous System Lymphoma

Primary central nervous system (CNS) lymphoma is a challenging subtypes of aggressive non-Hodgkin lymphoma. Emerging clinical data suggest that optimized outcomes are achieved with dose-intensive CNS-penetrant chemotherapy and avoiding whole brain radiotherapy. Anti-CD20 antibody-based immunotherapy as a component of high-dose methotrexate-based induction programs may contribute to improved outcomes. An accumulation of insights into the molecular and cellular basis of disease pathogenesis is providing a foundation for the generation of molecular tools to facilitate diagnosis as well as a roadmap for integration of targeted therapy within the developing therapeutic armamentarium for this challenging brain tumor.

Phase I and II Study of Induction Chemotherapy With Methotrexate, Rituximab, and Temozolomide, Followed By Whole-Brain Radiotherapy and Postirradiation Temozolomide for Primary CNS Lymphoma: NRG Oncology RTOG 0227

PURPOSE

This study investigated the treatment of primary CNS lymphoma with methotrexate, temozolomide (TMZ), and rituximab, followed by hyperfractionated whole-brain radiotherapy (hWBRT) and subsequent TMZ. The primary phase I end point was the maximum tolerated dose of TMZ. The primary phase II end point was the 2-year overall survival (OS) rate. Secondary end points were preirradiation response rates, progression-free survival (PFS), neurologic toxicities, and quality of life.

PATIENTS AND METHODS

The phase I study increased TMZ doses from 100 to 150 to 200 mg/m(2). Patients were treated with rituximab 375 mg/m(2) 3 days before cycle 1; methotrexate 3.5 g/m(2) with leucovorin on weeks 1, 3, 5, 7, and 9; TMZ daily for 5 days on weeks 4 and 8; hWBRT 1.2 Gy twice-daily on weeks 11 to 13 (36 Gy); and TMZ 200 mg/m(2) daily for 5 days every 28 days on weeks 14 to 50.

RESULTS

Thirteen patients (one ineligible) were enrolled in phase I of the study. The maximum tolerated dose of TMZ was 100 mg/m(2). Dose-limiting toxicities were hepatic and renal. In phase II, 53 patients were treated. Median follow-up for living eligible patients was 3.6 years, and 2-year OS and PFS were 80.8% and 63.6%, respectively. Compared with historical controls from RTOG-9310, 2-year OS and PFS were significantly improved (P = .006 and .030, respectively). In phase II, the objective response rate was 85.7%. Among patients, 66% (35 of 53) had grade 3 and 4 toxicities before hWBRT, and 45% (24 of 53) of patients experienced grade 3 and 4 toxicities attributable to post-hWBRT chemotherapy. Cognitive function and quality of life improved or stabilized after hWBRT.

CONCLUSION

This regimen is safe, with the best 2-year OS and PFS achieved in any Radiation Therapy Oncology Group primary CNS lymphoma trial. Randomized trials that incorporate this regimen are needed to determine its efficacy compared with other strategies.

New approaches in primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) has long been associated with an inferior prognosis compared to other aggressive non-Hodgkin's lymphomas (NHLs). However, during the past 10 years an accumulation of clinical experience has demonstrated that long-term progression-free survival (PFS) can be attained in a major proportion of PCNSL patients who receive dose-intensive consolidation chemotherapy and avoid whole brain radiotherapy. One recent approach that has reproducibly demonstrated efficacy for newly diagnosed PCNSL patients is an immunochemotherapy combination regimen used during induction that consists of methotrexate, temozolomide, and rituximab followed by consolidative infusional etoposide plus high-dose cytarabine (EA), administered in first complete remission (CR). Other high-dose chemotherapy-based consolidative regimens have shown efficacy as well. Our goal in this review is to update principles of diagnosis and management as well as data regarding the molecular pathogenesis of PCNSL, information that may constitute a basis for development of more effective therapies required to make additional advances in this phenotype of aggressive NHL.

Progress in central nervous system lymphomas

Until recently, primary central nervous system lymphoma (PCNSL) was associated with a uniformly dismal prognosis. It is now reasonable to anticipate long-term survival and possibly cure for a significant proportion of patients diagnosed with PCNSL. Accumulated data generated over the past 10 years has provided evidence that long-term progression-free survival (PFS) can reproducibly be attained in a significant fraction of PCNSL patients that receive dose-intensive chemotherapy consolidation, without whole brain radiotherapy. One consolidative regimen that has reproducibly demonstrated promise is the combination of infusional etoposide plus high-dose cytarabine (EA), administered in first complete remission after methotrexate, temozolomide and rituximab-based induction. Given evolving principles of management and the mounting evidence for reproducible improvements in survival rates in prospective clinical series, our goal in this review is to highlight and update principles in diagnosis, staging and management as well as to review data regarding the pathogenesis of central nervous system lymphomas, information that is likely to constitute a basis for the implementation of novel therapies that are requisite for further progress in this unique phenotype of non-Hodgkin lymphoma.

How I treat CNS lymphomas. Blood. 2013;122:2318-2330. [PMID: 23963042 DOI: 10.1182/blood-2013-06-453084]

The pathogenesis of primary and secondary central nervous system (CNS) lymphoma poses a unique set of diagnostic, prognostic, and therapeutic challenges. During the past 10 years, there has been significant progress in the elucidation of the molecular properties of CNS lymphomas and their microenvironment, as well as evolution in the development of novel treatment strategies. Although a CNS lymphoma diagnosis was once assumed to be uniformly associated with a dismal prognosis, it is now reasonable to anticipate long-term survival, and possibly a cure, for a significant fraction of CNS lymphoma patients. The pathogenesis of CNS lymphomas affects multiple compartments within the neuroaxis, and proper treatment of the CNS lymphoma patient requires a multidisciplinary team with expertise not only in hematology/oncology but also in neurology, neuroradiology, neurosurgery, clinical neuropsychology, ophthalmology, pathology, and radiation oncology. Given the evolving principles of management and the evidence for improvements in survival, our goal is to provide an overview of current knowledge regarding the pathogenesis of CNS lymphomas and to highlight promising strategies that we believe to be most effective in establishing diagnosis, staging, and therapeutic management.

Retrospective study of pemetrexed as salvage therapy for central nervous system lymphoma

There is currently no standard therapy for recurrent or chemotherapy-refractory central nervous system lymphoma (CNSL). Pemetrexed has been reported to have activity in patients with primary CNSL (PCNSL). The use of pemetrexed in secondary CNS lymphoma (SCNSL) has not previously been reported. Here we retrospectively review the outcomes and toxicities of standard and modified doses of pemetrexed as salvage therapy in 18 PCNSL and 12 SCNSL patients. The overall response rate for PCNSL patients was 64.7 %, all of whom achieved a complete response (CR). The median progression-free survival (PFS) was 5.8 months. For the SCNSL patients, RR was 58.3 % with 2 CR (16.7 %); the median PFS was 2.5 months. Grade ≥3 adverse events included leukopenia in 5 patients (16.7 %), neutropenia in 1 patient (3.3 %), and fatigue in 3 patients (10.0 %). 3 patients died while on treatment, 2 due to infections and 1 due to pulmonary embolism. Our results indicate that pemetrexed has activity as salvage therapy in recurrent PCNSL, even with modified dosing, but outcomes trend towards less favorable in SCNSL.

Initial testing (stage 1) of temozolomide by the pediatric preclinical testing program

BACKGROUND

The DNA methylating agent temozolomide was developed primarily for treatment of glioblastoma. However, preclinical data have suggested a broader application for treatment of childhood cancer. Temozolomide was tested against the PPTP solid tumor and ALL models.

PROCEDURES

Temozolomide was tested against the PPTP in vitro panel at concentrations ranging from 0.1 to 1,000 µM and was tested against the PPTP in vivo panels at doses from 22 to 100 mg/kg administered orally daily for 5 days, repeated at day 21.

RESULTS

In vitro temozolomide showed cytotoxicity with a median relative IC50 (rIC50 ) value of 380 µM against the PPTP cell lines (range 1 to > 1,000 µM). The three lines with rIC50 values lesser than 10 µM had low MGMT expression compared to the remaining cell lines. In vivo temozolomide demonstrated significant toxicity at 100 mg/kg, but induced tumor regressions in 15 of 23 evaluable solid tumor models (13 maintained CR [MCR], 2 CR) and 5 of 8 ALL models (3 MCR, 2 CR). There was a steep dose response curve, with lower activity at 66 mg/kg temozolomide and with tumor regressions at 22 and 44 mg/kg restricted to models with low MGMT expression.

CONCLUSIONS

Temozolomide demonstrated high level antitumor activity against both solid tumor and leukemia models, but also elicited significant toxicity at the highest dose level. Lowering the dose of TMZ to more closely match clinical exposures markedly reduced the antitumor activity for many xenograft lines with responsiveness at lower doses closely related to low MGMT expression.

Immunochemotherapy with intensive consolidation for primary CNS lymphoma: a pilot study and prognostic assessment by diffusion-weighted MRI

PURPOSE

We evaluated a novel therapy for primary central nervous system lymphoma (PCNSL) with induction immunochemotherapy with high-dose methotrexate, temozolomide, and rituximab (MT-R) followed by intensive consolidation with infusional etoposide and high-dose cytarabine (EA). In addition, we evaluated the prognostic value of the minimum apparent diffusion coefficient (ADC(min)) derived from diffusion-weighted MRI (DW-MRI) in patients treated with this regimen.

EXPERIMENTAL DESIGN

Thirty-one patients (median age, 61 years; median Karnofsky performance score, 60) received induction with methotrexate every 14 days for 8 planned cycles. Rituximab was administered the first 6 cycles and temozolomide administered on odd-numbered cycles. Patients with responsive or stable central nervous system (CNS) disease received EA consolidation. Pretreatment DW-MRI was used to calculate the ADC(min) of contrast-enhancing lesions.

RESULTS

The complete response rate for MT-R induction was 52%. At a median follow-up of 79 months, the 2-year progression-free and overall survival were 45% and 58%, respectively. For patients receiving EA consolidation, the 2-year progression-free and overall survival were 78% and 93%, respectively. EA consolidation was also effective in an additional 3 patients who presented with synchronous CNS and systemic lymphoma. Tumor ADC(min) less than 384 × 10(-6) mm(2)/s was significantly associated with shorter progression-free and overall survival.

CONCLUSIONS

MT-R induction was effective and well tolerated. MT-R followed by EA consolidation yielded progression-free and overall survival outcomes comparable to regimens with chemotherapy followed by whole-brain radiotherapy consolidation but without evidence of neurotoxicity. Tumor ADC(min) derived from DW-MRI provided better prognostic information for PCNSL patients treated with the MTR-EA regimen than established clinical risk scores.

Salvage treatment with temozolomide in refractory or relapsed primary central nervous system lymphoma and assessment of the MGMT status

High-dose methotrexate (HD-MTX) is effective in the initial treatment of primary central nervous system lymphoma (PCNSL). Because treatment options in patients with progressive or recurrent PCNSL are limited, prognosis is poor. Temozolomide, a well-tolerated oral alkylating agent that permeates the blood brain barrier (BBB), is effective against malignant glioma and recurrent PCNSL. The gene for the deoxyribonucleic acid (DNA) repair enzyme O(6)-methylguanine-DNA methyltransferase (MGMT), which is closely related to cellular sensitivity to alkylating agents, is inactivated by promoter hypermethylation. We evaluated the results of temozolomide treatment and the methylation status of the promoter region of the MGMT gene in 17 patients (median age 68 years) with refractory or relapsed PCNSL. They were immunocompetent and had received initial treatment with HD-MTX (3.5 g/m(2)) with or without irradiation. All were treated with temozolomide 150-200 mg/m(2), for 5 days in the course of 28 days; treatment was continued until disease progression. We observed five complete remissions, five partial responses (PRs) with stable disease (SD), and seven with disease progression. Median overall survival after the temozolomide treatment was 6.7 months. One patient manifested grade 3 neutropenia and thrombocytopenia. Eleven tumor specimens were available for MGMT analysis. MGMT promoter methylation (mMGMT) in the tumor tissue was found in 4 (36.4%), the other seven harbored a non-methylated MGMT promoter (nmMGMT). There was no statistically significant difference in median overall survival between patients with mMGMT (11.1 months) and nmMGMT (6.7 months) (P = 0.63). Although some patients were elderly and had been heavily pre-treated, temozolomide resulted in a complete response (CR) in 29% and was well tolerated without any major toxicity.

Temozolomide and methotrexate for primary central nervous system lymphoma in the elderly

BACKGROUND

Treatment for primary CNS lymphoma (PCNSL) in the elderly is associated with lower response rates and higher risks of acute and late delayed toxicity as compared to younger patients. Temozolomide has emerged as a new alternative treatment for PCNSL and constitutes an attractive option for the elderly because of its favorable toxicity profile. In this study we report outcomes of a consecutive series of PCNSL elderly patients initially treated with an innovative regimen combining methotrexate and temozolomide without radiotherapy or intra-thecal chemotherapy.

METHODS

Histologically confirmed newly-diagnosed PCNSL patients older than 60 years were included. An induction chemotherapy was initially given (methotrexate 3 g /m(2) on days 1, 10, and 20, and temozolomide 100 mg/m(2) on days 1-5). Patients achieving a partial or complete response proceeded to a maintenance phase (up to 5 monthly cycles of methotrexate 3 g/m(2) on day 1, and temozolomide 100 mg/m(2 )days 1-5). Non-responders were treated on an individual basis.

RESULTS

Among the 23 included patients, a complete response was observed in 55%, and disease progressed in the other 45%. Median event-free survival was 8 months, and median overall survival was 35 months. Grades 3 or 4 toxicities included nephrotoxicity in three patients, and hematotoxicity in five; no neurotoxicity has been observed to date. One patient died while on treatment from complications of intestinal obstruction.

CONCLUSION

Our efficacy results are comparable to other reported regimens, with the advantages of a favorable toxicity profile, and absence of intra-thecal chemotherapy. Prospective, controlled studies are warranted to confirm such results.

Complete response to temozolomide treatment in an elderly patient with recurrent primary central nervous system lymphoma--case report

An 80-year-old woman presented with primary central nervous system (CNS) lymphoma manifesting as progressive disorientation and loss of activity. She received three cycles of high-dose methotrexate. The tumor shrank after two cycles and her mental status improved, but she suffered tumor recurrence. The second-line treatment consisted of four cycles of rituximab but the tumor enlarged. She was then treated with three cycles of temozolomide. Magnetic resonance imaging revealed no evidence of disease. Her mental status and performance status improved, and she suffered no toxicity. She is able to pursue her daily life without recurrence after 16 cycles of temozolomide. Temozolomide may be effective against relapsed primary CNS lymphoma without causing neurotoxicity in the elderly.

Chemotherapy for primary central nervous system lymphoma

✓Chemotherapy, with or without radiotherapy, is the mainstay of treatment for primary central nervous system lymphoma (PCNSL). High-dose methotrexate (MTX) is the most effective drug available to treat these lesions, and it is used in doses of 1 to 8 g/m2, either as a single agent or in combination with other drugs such as corticosteroid agents, cytarabine, procarbazine, vincristine, carmustine, lomustine, thiotepa, cyclophosphamide, temozolomide, and rituximab. To date, an overwhelming number of different regimens in which high-dose MTX is used have been reported. Given the lack of randomized trials, however, the optimal treatment remains controversial. Varying methodology makes the comparison of available studies extremely difficult, yet some common themes can be found throughout the literature. Treatment paradigms vary considerably according to the patient's age. Most studies support the use of chemotherapy-only treatments for elderly patients (> 60 years), given the high risks of neurotoxicity associated with radiotherapy. Nevertheless, the prognosis remains poor regardless of the chemotherapy chosen, and less toxic regimens might be preferable for such elderly patients. Conversely, in younger patients (< 60 years), there is growing evidence that commonly used chemotherapy-only regimens are associated with increased relapse rates that may not justify deferral of radiotherapy. Thus, a significant focus of research has been the development of intensified chemotherapy regimens that could replace radiotherapy. In this article, the authors discuss the principles guiding the use of chemotherapy for PCNSL, and critically review the available literature, including the most recent trials.

Temozolomide: a milestone in neuro-oncology and beyond?

Temozolomide (Temodal, Temodar), an imidazol derivative, is a second-generation alkylating agent. The orally available prodrug with the capacity of crossing the blood-brain barrier received accelerated US FDA approval in 1999. Three pivotal Phase II trials showed modest activity in the treatment of recurrent anaplastic astrocytoma glioblastoma. In 2005, the FDA and the European Agency for the Evaluation of Medicinal Products approved temozolomide for use in newly diagnosed glioblastoma, in conjunction with radiotherapy, based on an European Organisation for Research and Treatment of Cancer/National Cancer Institute of Canada Phase III trial. The adverse events associated with temozolomide are mild-to-moderate and generally predictable; the most serious are noncumulative and reversible myelosuppression and, in particular, thrombocytopenia, which occurs in less than 5% of patients. Continuous temozolomide administration is associated with profound CD4-selective lymphocytopenia. Molecular studies have suggested that the benefit of temozolomide chemotherapy is restricted to patients whose tumors have a methylated methylguanine methyltransferase gene promotor and are thus unable to repair some of the chemotherapy-induced DNA damage. Temozolomide is under investigation for other disease entities, in particular lower-grade glioma, brain metastases and melanoma.

Treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) describes a malignant non-Hodgkin's lymphoma (NHL) whose sole site of involvement is the central nervous system (CNS). The diagnosis of PCNSL must be differentiated from systemic NHL with metastasis to the CNS, which usually occurs late in the course of systemic disease. PCNSL accounts for approximately 4% to 7% of primary brain tumors, and its incidence has been increasing since the mid-1970s. Compared with other more common malignant primary brain tumors, PCNSL tends to be more amenable to radiotherapeutic and chemotherapeutic intervention. In this article, the authors review the standard treatment for upfront and recurrent PCNSL.

Diagnosis and treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is an uncommon form of non-Hodgkin's lymphoma (NHL) that has been increasing in incidence over the past three decades. Unlike systemic extranodal NHL, the response to therapy for PCNSL patients has been somewhat unsatisfactory. However, methotrexate-based chemotherapy and whole-brain radiotherapy have improved the outcome of patients. Unfortunately, treatment-related neurotoxicity is common, especially in the elderly. Although progress has been made in treating PCNSL, there remains no optimal methotrexate dose or frequency. Treatment of recurrence also remains controversial. These important questions have prompted several clinical studies looking at novel ways to intensify chemotherapy and limit neurotoxicity.

Primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare variant of non-Hodgkin's lymphoma that is increasing in incidence. Methotrexate-based chemotherapy in combination with whole-brain radiotherapy (WBRT) has dramatically improved the outcome of patients. However, treatment-related neurotoxicity is a significant complication, especially after radiotherapy in the elderly. Despite advances in therapy, several important questions remain regarding optimal methotrexate dose, dosing frequency, adjunct chemotherapy, and the impact of deferring WBRT. Advances in biologic therapy and strategies to intensify the delivery of chemotherapy may help to limit the use of radiotherapy, thus lessening potential neurotoxicity. Studies looking at oncogenic proteins as potential prognostic markers for PCNSL may help us to develop risk-adapted therapies.

Immunochemotherapy with rituximab and temozolomide for central nervous system lymphomas

BACKGROUND

Methotrexate-based and alkylator-based chemotherapy regimens are associated with renal and bone marrow toxicities, which limit their use in patients with central nervous system (CNS) lymphomas. The authors report their experience with an immunochemotherapy regimen consisting of rituximab and temozolomide in patients with primary or metastatic CNS lymphoma.

METHODS

Seven patients who had received rituximab and temozolomide were identified from the database of the brain tumor clinic at the authors' institution: three patients had developed recurrent primary CNS lymphoma (PCNSL), one patient had newly diagnosed PCNSL but had poor renal function, and three other patients with systemic non-Hodgkin lymphoma developed recurrent lymphoma in the brain only. Patients were scheduled to receive 4 cycles of induction rituximab on Day 1 and temozolomide on Days 1-5 of a 28-day cycle. Thereafter, their treatment included a total of up to 8 maintenance cycles of temozolomide alone on Days 1-5 of a 28-day cycle. A gadolinium-enhanced magnetic resonance image of the head was obtained after every two cycles of treatment.

RESULTS

All patients received rituximab without toxicity. Of the 4 patients who received induction temozolomide at doses > 150 mg/m(2) daily on Days 1-5, 2 experienced Grade 2 leukopenia and thrombocytopenia. Five patients achieved a radiographic complete response, and two patients had partial responses after induction treatment. The median response duration was 6 months (range 3-12+ months), and the median survival was 8 months (range 3+-12+ months).

CONCLUSIONS

Although median survival was short, immunochemotherapy with rituximab and temozolomide was well tolerated and exhibited efficacy in this elderly and heavily pretreated cohort. The data obtained in the current study suggest that the optimal induction dose combination consists of rituximab 375 mg/m(2) on Day 1 and temozolomide 150 mg/m(2) daily on Days 1-5.

Salvage chemotherapy with temozolomide in primary CNS lymphomas: preliminary results of a phase II trial

Temozolomide is a well-tolerated alkylating agent, that is able to permeate the blood-brain barrier (BBB), and has additive cytotoxicity when given with radiotherapy (RT). A phase II trial assessing temozolomide 150 mg/m(2)/day, for 5 days every 28 days in primary central nervous system (CNS) lymphoma (PCNSL) patients with negative human immunodeficiency virus (HIV) serology, Eastern Cooperative Oncology Group (ECOG) performance status (PS)<4, previously treated with high-dose methotrexate-containing (HD-MTX) chemotherapy and/or RT was started. Twenty-three patients were enrolled. Median age was 60 years. Five complete remissions (median duration 6+ months; range 2-36 months), one partial response, four stable disease (median duration 7.2 months, range 2-16.5 months), and 13 progressions were observed. No major toxicities were observed, apart grade 3 vomiting in a single cycle. Main grade 1-2 toxicities were: 15% nausea, 6% vomiting, 9% fatigue and 9% neurological symptoms. This is the first prospective trial assessing single-agent activity in PCNSL at failure. Although some patients had a poor PS and had been heavily pre-treated, temozolomide yielded 26% objective responses and was well tolerated without any major toxicity.

Primary cultures of microglial cells for testing toxicity of anticancer drugs

Toxicity of anticancer agents on normal neural cells during chemotherapy of primary or secondary brain tumors is a clinical problem of increasing relevance and concern. In this perspective, here we used primary cultures of rat cortical microglia as an in vitro paradigm of normal glia to investigate the neurotoxicity of anticancer agents. The effects of two compounds frequently used for treatment of brain tumors, methotrexate (MTX) and temozolomide (TMZ), were compared to those of a known microglial activator, bacterial lipopolysaccharide (LPS); cell viability and metabolism was assessed by the MTS assay. We found that LPS, in the low-intermediate range of concentrations, strongly activates microglia cells, but a highly significant decrease in viability was observed from 100 ng/ml onward. TMZ has no effect at concentrations of clinical interest, whereas MTX significantly increases cell metabolism at 30 microM, a phenomenon possibly reflecting MTX neurotoxicity observed in patients.

Treatment of primary central nervous system lymphoma in the elderly

Although the incidence of primary central nervous system lymphoma has recently declined among people with acquired immunodeficiency syndrome, the incidence of primary central nervous system lymphoma remains high among the immunocompetent population >/=60 years of age. Elderly patients represent an important subgroup that accounts for approximately half of primary central nervous system lymphoma cases. Radiotherapy (RT) alone has produced disappointing results in the elderly. Improved clinical outcomes have been achieved with high-dose methotrexate-based chemotherapy regimens in combination with whole-brain RT. Unfortunately, combination therapy exposes elderly patients to a high risk of severe delayed neurotoxicity in up to 80%. Chemotherapy alone may be the best approach for treating elderly patients and appears to be more effective than RT, while considerably reducing the risk of neurotoxicity. Clinical studies are needed to define the optimal chemotherapy regimen for the elderly in an effort to delay or completely avoid the need for RT.

Primary central nervous system lymphoma: results of a pilot and phase II study of systemic and intraventricular chemotherapy with deferred radiotherapy

PURPOSE

To evaluate response rate, response duration, overall survival (OS), and toxicity in primary CNS lymphoma (PCNSL) after systemic and intraventricular chemotherapy with deferred radiotherapy.

PATIENTS AND METHODS

From September 1995 to July 2001, 65 consecutive patients with PCNSL (median age, 62 years) were enrolled onto a pilot and phase II study evaluating chemotherapy without radiotherapy. A high-dose methotrexate (MTX; cycles 1, 2, 4, and 5) and cytarabine (ARA-C; cycles 3 and 6)-based systemic therapy (including dexamethasone, vinca-alkaloids, ifosfamide, and cyclophosphamide) was combined with intraventricular MTX, prednisolone, and ARA-C.

RESULTS

Sixty-one of 65 patients were assessable for response. Of these, 37 patients (61%) achieved complete response, six (10%) achieved partial response, and 12 (19%) progressed under therapy. Six (9%) of 65 patients died because of treatment-related complications. Follow-up is 0 to 87 months (median, 26 months). The Kaplan-Meier estimates for median time to treatment failure (TTF) and median OS were 21 months and 50 months, respectively. For patients older than 60 years, median survival was 34 months, and the median TTF was 15 months. In patients younger than 61 years, median survival and median TTF have not been reached yet; the 5-year survival fraction is 75%. Systemic toxicity was mainly hematologic. Ommaya reservoir infection occurred in 12 patients (19%), and permanent cognitive dysfunction possibly as a result of treatment occurred in only two patients (3%).

CONCLUSION

Primary chemotherapy based on high-dose MTX and ARA-C is highly efficient in PCNSL. Response rate and response duration in this series are comparable to the response rates and durations reported after combined radiotherapy and chemotherapy. Neurotoxicity was infrequent.

Summary statement on primary central nervous system lymphomas from the Eighth International Conference on Malignant Lymphoma, Lugano, Switzerland, June 12 to 15, 2002

Under the sponsorship of the International Extranodal Lymphoma Study Group, a Multidisciplinary Workshop on primary CNS lymphoma (PCNSL) with over 50 participants from Europe, North America, Israel, and Australia was held as part of the Eighth International Conference on Malignant Lymphoma in Lugano, Switzerland (June 12 to 15, 2002). The main purposes of the Workshop were to exchange the latest scientific information, to analyze methodologic issues in the design of clinical trials, to reach a consensus on treatment recommendations and prognostic factors, to discuss clinical and molecular targets for future studies, and to establish an international collaborative group to conduct laboratory and clinical investigations in PCNSL. This article summarizes the contents of the Workshop, analyzes the current knowledge on the most relevant biologic and clinical issues in PCNSL, and focuses on fundamental challenges to be addressed in future studies.

Salvage treatment with etoposide (VP-16), ifosfamide and cytarabine (Ara-C) for patients with recurrent primary central nervous system lymphoma

BACKGROUND

Survival of patients with primary central nervous system lymphoma (PCNSL) has improved with methotrexate-based combination regimens and radiotherapy (RT). However, the prognosis of patients who fail or relapse after initial response is poor. Very little data is available on salvage treatment at recurrence.

PATIENTS AND METHODS

Sixteen immunocompetent patients (13 males/three females, median age 54 yr) with refractory (one patient) or recurrent (15 patients) PCNSL, homogeneously treated at diagnosis with the cyclophosphamide, doxorubicin, vincristine, dexamethasone/carmustine, vincristine, cytarabine and methotrexate (CHOD/BVAM) and RT regimen, received etoposide (VP-16), ifosfamide and cytarabine (Ara-C) (VIA) chemotherapy as a salvage treatment. VIA included etoposide 100 mg/m2/d days 1-3, ifosfamide 1000 mg/m2/d days 1-5, and cytarabine 2000 mg/m2/12 h day 1. The therapy was repeated every 28 d for a total of planned six cycles.

RESULTS

Median time between first complete response (CR) and relapse was 19 months (range: 6-46 months). Thirteen patients (81%) had a performance status <or=2, six had multifocal PCNSL and six (of eight tested) positive cerebrospinal fluid cytology. The median number of courses per patient was four (range: 1-6). Five patients completed the whole VIA therapy. Six patients (37%) achieved CR. After a median follow-up of 15 months for surviving patients, two have relapsed, with a median failure-free survival of 5 months. Twelve patients have died from progression of PCNSL, with a 12-month overall survival of 41% [95% confidence interval (CI): 16-66]. The major toxicity was World Health Organization grade 2-4 neutropenia (69% of patients) and thrombocytopenia (50%). Five patients had grade 3-4 infectious complications. Finally, one patient developed a severe but reversible ifosfamide encephalopathy.

CONCLUSION

The data presented show that the chemotherapy VIA is an effective salvage regimen for patients with recurrent PCNSL.

Case report: a patient with primary CNS lymphoma treated with temozolomide to complete response

We report the case of a 72-year-old woman with primary CNS lymphoma of the mid-brain and pons who had a complete response to oral temozolomide chemotherapy. She initially presented in early 2001 with several weeks of progressive memory loss and unresponsiveness. Because of her age and impaired renal function, she was a poor candidate for whole-brain radiotherapy or systemic high-dose methotrexate. After treatment with two cycles of temozolomide, restaging MRI revealed no evidence of disease. Her mental status improved significantly over this time. Temozolomide may represent a promising new drug for the treatment of primary CNS lymphoma.

Diagnostic advances and new trends for the treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare non-Hodgkin's lymphoma arising in the brain. Recent increase in its incidence has been noted both in immunocompetent individuals and patients with immunodeficiency. This review will focus on the epidemiology, pathogenesis, diagnosis and treatment of this aggressive extranodal lymphoma in immunocompetent patients. Stereotactic biopsy is usually required for diagnosis, while molecular biology and/or cytofluorimetric analysis may confirm the presence of clonal proliferation in the cerebrospinal fluid (CSF). Methotrexate-based chemotherapy plus whole-brain radiotherapy are the standard treatment for PCNSL and achieve a high rate of complete remissions (CR), but long-term neurotoxicity may heavily compromise the patient's quality of life. The metabolic rate of controversial gadolinium-enhancing lesions on magnetic resonance (MR) scans may be assessed with positron emission tomography (PET), which discriminates radiation necrosis from true recurrence. Withholding radiotherapy in patients achieving CR after first-line chemotherapy is a new and interesting treatment option, while the role of high-dose chemotherapy with stem cell rescue is still uncertain.

Combined treatment with temozolomide and poly(ADP-ribose) polymerase inhibitor enhances survival of mice bearing hematologic malignancy at the central nervous system site

Temozolomide (TZM) is a DNA-methylating agent that has recently been introduced into various clinical trials for treatment of solid or hematologic neoplasias, including brain lymphomas. In the current study, we have investigated whether the antitumor activity of TZM could be selectively enhanced at the central nervous system (CNS) site by intracerebral injection of a poly(ADP-ribose) polymerase (PARP) inhibitor. Mice were injected intracranially with lymphoma cells. The PARP inhibitor NU1025 (1 mg/animal) was delivered intracerebrally, whereas TZM was given as a single or a fractionated dose of 200 mg/kg by intraperitoneal administration. Results indicated that this drug combination significantly enhanced the survival of tumor-bearing mice and that this fractionated modality of treatment was the most effective schedule. Increased survival time was related to a marked reduction of tumor growth, as evidenced by histologic studies. Treatment with TZM alone was ineffective. This is the first report exploring in vivo the combination of TZM with PARP inhibitor for intracerebral neoplasias.

Potential clinical applications of poly(ADP-ribose) polymerase (PARP) inhibitors

Poly(ADP-ribose) polymerases (PARPs) are defined as cell signaling enzymes that catalyze the transfer of ADP-ribose units from NAD(+)to a number of acceptor proteins. PARP-1, the best characterized member of the PARP family, that presently includes six members, is an abundant nuclear enzyme implicated in cellular responses to DNA injury provoked by genotoxic stress (oxygen radicals, ionizing radiations and monofunctional alkylating agents). Due to its involvement either in DNA repair or in cell death, PARP-1 is regarded as a double-edged regulator of cellular functions. In fact, when the DNA damage is moderate, PARP-1 participates in the DNA repair process. Conversely, in the case of massive DNA injury, elevated PARP-1 activation leads to rapid NAD(+)/ATP consumption and cell death by necrosis. Excessive PARP-1 activity has been implicated in the pathogenesis of numerous clinical conditions such as stroke, myocardial infarction, shock, diabetes and neurodegenerative disorders. PARP-1 could therefore be considered as a potential target for the development of pharmacological strategies to enhance the antitumor efficacy of radio- and chemotherapy or to treat a number of clinical conditions characterized by oxidative or NO-induced stress and consequent PARP-1 activation. Moreover, the discovery of novel functions for the multiple members of the PARP family might lead in the future to additional clinical indications for PARP inhibitors.

Pharmacotherapy of primary CNS lymphoma

Primary CNS lymphoma (PCNSL) is distinguished from other brain tumours by its striking response to chemotherapy. Surgery has little role (if any) in the treatment of PCNSL. Radiation therapy has been proven to prolong survival but its use is complicated by delayed neurological toxicity, particularly among the elderly. Progress in understanding the physiology of the blood-brain barrier (BBB) and the pharmacology of chemotherapeutic agents has substantially improved the treatment and prognosis of this disease. The single most effective agent is methotrexate (MTX). The goal of delivering an adequate dose of MTX to the brain and the cerebrospinal fluid (CSF) has been achieved by a variety of strategies, including systemic high dose, intra-arterial injection following pharmacological disruption of the BBB and intrathecal (it.) administration. MTX-based combination chemotherapy has yielded the best results to date but the prognosis of patients with PCNSL remains significantly worse than comparable patients with systemic non-Hodgkin's lymphoma (NHL). Ongoing trials continue to test novel combinations of agents, doses and improved routes of delivery with the hope of improving disease control and diminishing treatment-related neurotoxicity.

Current and future developments in the use of temozolomide for the treatment of brain tumours

Brain tumours comprise only 2% of all adult cancers, but they are among the most debilitating malignant diseases. Temozolomide, an alkylating agent that can be administered orally, has been approved for the treatment of recurrent malignant glioma on a daily schedule for 5-day cycles. Continuous administration schedules with a higher dose intensity are being explored, but an improvement in efficiency remains to be shown. The benefit from temozolomide given as a single agent in recurrent disease will be several weeks at best. This drug is therefore now undergoing clinical testing as neoadjuvant chemotherapy or with concomitant radiotherapy in patients with newly diagnosed glioma. Several phase I trials are investigating the combination of temozolomide with other agents active against brain tumours. This review briefly summarises the pharmacological background and clinical development of temozolomide and focuses on current and future clinical exploration of this drug for the treatment of brain tumours.

Primary central nervous system lymphomas

Primary central nervous system lymphoma (PCNSL) is widely regarded as one of the primary brain tumors most amenable to treatment. Although whole brain radiotherapy was the cornerstone of therapy for decades, recent work clearly indicates that chemotherapy has become the primary focus of treatment for this disease. The initial treatment of PCNSL for all patients, including the elderly, should be chemotherapy using a high-dose methotrexate-based regimen. Although cranial irradiation has often been combined with methotrexate, the unacceptably high incidence of late neurotoxicity, particularly in older patients, has caused many to eliminate radiotherapy, especially in those older than age 60 years. Emerging data support the validity of this approach, and the development of more efficacious chemotherapeutic regimens has been the focus of recent research.