Liposomal Cytarabine as Cancer Therapy: From Chemistry to Medicine

Cancer is the second leading cause of death worldwide. The main modality to fight against cancer is surgery, radiotherapy, and chemotherapy, and more recently targeted therapy, gene therapy and immunotherapy, which play important roles in treating cancer patients. In the last decades, chemotherapy has been well developed. Nonetheless, administration of the drug is not always successful, as limited drug dosage can reach the tumor cells.. In this context, the possibility to use an encapsulated anti-cancer drug may potentially solve the problem. Liposomal cytarabine is a formulation with pronounced effectiveness in lymphomatous meningitis and reduced cardiotoxicity if compared to liposomal anthracyclines. Thus, the future liposomal cytarabine use could be extended to other diseases given its reduction in cytotoxic side effects compared to the free formulation. This review summarizes the chemistry and biology of liposomal cytarabine, with exploration of its clinical implications.

Flow Cytometric Detection of Liposomes in the CSF of Patients with NHL/ALL, Treated with Intrathecal Liposomal Cytarabine: Synonymous of Toxicity?

Objectives Patients with aggressive non-Hodgkin’s lymphoma (NHL) and acute lymphoblastic leukemia (ALL) with high risk of CNS infiltration or recurrence may receive prophylaxis or be treated with intrathecal injections (IT) of liposomal cytarabine (LC) once every 2 weeks (due to its sustained release of cytarabine). Sequential flow cytometric studies in patients with CNS involvement and treated with LC, allow to detect tumor cells as well as LC liposomes (LCL) in the CSF. The true meaning of the presence of these liposomes during the treatment with LC is still unknown. Patients and Methods In this study, we aimed to investigate the presence of LCL detected by Flow Cytrometry (FC) among 166 CSF samples of 69 patients treated with LC. Samples were taken before each administration of intrathecal LC and centrally processed. Results Results are shown in the below table. Abstract 5444. Table 1Patients with NHL/ALL, treated with Intrathecal Liposomal CytarabineNPatients69Samples166Liposomal Cytarabine Liposomes (LCL) in CSFN%Patients1319%DLBCL646%LLT215%ALL215%MCL18%MM18%CLL18%Samples2616%Males862%2616%Age66 years[33-84]LCL in CSF of patients receiving Liposomal CytarabinePROPHYLAXISNToxycityTotal nº of IT LC dosesPatients7nº of IT LC doses*3 (2-5).LCL7After 1st dose5After 2nd dose21 LLT patient: arachnoiditis, high intrathecal pressure, papillitis, without sequelae5After 3rd dose2After 5th dose1LCL in CSF of patients receiving Liposomal Cytarabine leptomeningeal disease TREATMENTNTumor: ToxycityTotal nº of IT LC dosesPatients6nº of IT LC doses*6 (4-7)LCL6After 1st dose31 DLBCL patient: Headache, dizziness and instability51 MM patient: Headache, dizziness and instability4After 3rd dose2After 5th dose11 ALL patient: Headache, dizziness and instability7 * Median [range] The thirteen patients were simultaneously treated with LC and IT + IV dexamethasone. It was found no relationship between the amount of LCL and toxicity. Conclusions: Presence of LCL in CSF is detected in 15-20% of patients receiving IT LC as prophylaxis / treatment and it does not show a direct relationship with presence of toxicity. Although the true clinical significance of the presence of LCL in CSF remains unknown, their monitoring could be useful to individualize the treatment with CL IT (dose and time between doses). Disclosures Off Label Use: Liposomal cytarabine is not approved for prophylaxys of lymphomatous meningitis..

A Multicentric Prospective Phase 2 Study of Intravenous Rituximab and Intrathecal Liposomal Cytarabine in Combination with C5R Protocol Followed by Brain Radiotherapy for Immunocompetent Patients with Primary CNS Lymphoma: A Lymphoma Study Association (LYSA) Trial

Abstract 796 Background: The LNHCP93 trial is an intensive high-dose methotrexate and cytarabine containing chemotherapy (CT) derived from CT regimens used for Burkitt lymphomas (C5R protocol) followed by brain radiotherapy (RT) showing favourable long-term survival in Primary CNS Lymphoma (PCNSL) patients younger than 60 years: the complete response (CR) rate was 33%, the 5-year progression-free survival (PFS) and overall survival (OS) rates were 31% and 42%, respectively with however 9% of toxic death. Rituximab improves outcome of systemic Diffuse Large B-Cell Lymphoma (DLBCL) but it is unclear if its addition is useful in PCNSL with DLBCL histology. Intrathecal (IT) liposomal cytarabine (Depocyt) which shows a long-CSF half-life and better efficacy compared to IT methotrexate and free cytarabine in lymphomatous meningitis is also an attractive treatment for PCNSL. Methods: In order to improve antitumor activity of C5R protocol, we prospectively evaluated the addition of intravenous rituximab and IT liposomal cytarabine to CT before RT for 18 to 60 years old immunocompetent patients with PCNSL. The primary objective of this study is the complete and unconfirmed complete response rate (CR/CRu) after immuno-CT, according to International Primary CNS Lymphoma Collaborative Group response criteria. The number of patients was calculated in order to improve the 30% CR/CRu rate of LNHCP93 study up to 50%. The secondary objectives were side effect profile including acute and late neurological toxicities, PFS and OS. Patients received two courses of methotrexate, cyclophosphamide, doxorubicin, vincristine, prednisone (COPADEM) followed by two courses of methotrexate, cytarabine (CYM) administred at 21-day intervals from day 1 to day 21. At each day 1, intravenous rituximab 375mg/m2and at each day 3 IT liposomal cytarabine 50mg were infused. After immuno-CT, a brain RT was planned for all patients. A new response assessment was performed after RT. Patients were followed every 4 months for the first two years and then every 6 months. Neurotoxicity was evaluated by a Mini-Mental State Examination (MMSE) test. Results: Fifty-three PCNSL patients with a confirmed diagnosis of CD20 positive DLBCL were included between August 2007 and September 2011: median age was 55 years (range, 36–60), 57% were male, 42% had a performance status >1, 55% had an involvement of deep structures of brain, 45% a high CSF protein level and 36% a high LDH level. Median MMSE score assessed for 42 patients at baseline was 26 (range 3–30). After immuno-CT, 22 patients achieved a CR and 13 a CRu (CR + CRu, 66%), 7 a partial response (13%), 6 had a stable or progressive disease (11%) and 5 (10%) were not evaluated due to early death (n=2) or toxicities (n=3). For 45 patients who completed the fourth cycles, CR/CRu rate was 75.6%. Thirty-one patients (58%) presented at least one serious adverse event, mainly infections (25 patients, 47%). At least one red blood cell and platelet transfusions were given in 94% and 68% of patients, respectively and 57% of patients experienced a febrile neutropenia. Forty-two patients (79%) underwent RT, 23 of them with a reduced whole brain RT (median 26 Gy) and a boost to the tumor bed. With a median follow-up of 22 months, 15 patients progressed or relapsed (28.3%) and 13 patients died (24.5%), 3 (5.7%) of them from acute toxicity. The 2-year PFS and OS rates are 67% (95%CI, 50.0% to 79.4%) and 82% (95%CI, 67.0% to 90.7%), respectively. Median MMSE score was 27 (range, 26–30) for the 7 patients evaluated between 12 and 18 months after the beginning of treatment. Conclusions: With the addition of intravenous rituximab and intrathecal liposomal cytarabine, C5R protocol provided higher CR/CRu rate and promising outcome results with a 2-year PFS of 67% as compared to historical controls. No additional severe toxicities were observed compared to C5R protocol and with short follow-up no neurocognitive decline was observed. Disclosures: Off Label Use: Depocyt (intrathecal liposomal cytarabine) is off-label used in first line therapy of Primary CNS Lymphoma but approval for treatment of lymphomatous meningitis. Morschhauser:Roche: Honoraria. Blay:Roche: Honoraria, Research Funding.