Kurtin, Paul J.

Abstract Abstract 4136 Background: The serum free light chain (FLC) assay quantitates free kappa and free lambda immunoglobulin light chains. This assay has prognostic value in MGUS, multiple myeloma (MM), solitary plasmacytoma, and amyloid light chain (AL) amyloidosis, and has been incorporated in response criteria for both MM and AL amyloidosis. We previously showed elevated FLC was associated with poor outcome in diffuse large B-cell lymphoma (DLBCL) patients from a phase II cooperative group clinical trial (Blood (ASH Annual Meeting Abstracts) 2009 November 20, 2009; 114(22): 136). Here we replicate those findings in a large clinic based epidemiology cohort, as well as examine FLC abnormalities in other lymphoma subtypes. Methods: Newly diagnosed lymphoma patients were prospectively enrolled in the University of Iowa/Mayo Clinic SPORE Molecular Epidemiology Resource (MER). Serum FLC was quantitated from enrollment research serum draws within 9 months of diagnosis using the Freelite FLC assay (The Binding Site, Ltd., Birmingham, UK). Elevated FLC was defined as either kappa or lambda above the published reference range. Monoclonal elevated FLC was defined as elevated FLC with an abnormal FLC ratio; polyclonal elevated FLC was defined as elevated FLC with an FLC ratio in the normal reference range. Clinical data was abstracted using a standard protocol for the MER and patients were followed systematically for event-free (progression, retreatment, or death due to any cause) and overall survival (EFS and OS, respectively). Cox proportional hazards models were used to evaluate the unadjusted association between FLC and outcome. Results: 1118 lymphoma patients diagnosed between September 2002 and February 2008 with available serum were assayed. At a medium follow-up of 49 months (range 1–94), 484 patients (43%) had an event and 249 patients died (22%). Elevated FLC was present in 27% of lymphomas, with prevalence ranging from 13% in follicular lymphoma (FL) to 64% for mantle cell lymphoma (MCL) and 77% for lymphoplasmacytic lymphoma. Elevated FLC was present in 27% of DLBCL and associated with poor EFS (monoclonal hazard ratio (HR)=2.56, polyclonal HR=1.99, all p<0.001) and OS (monoclonal HR=3.22, polyclonal HR=2.91, all p<0.0001), replicating our previous findings. Elevated FLC was generally polyclonal (FLC ratio normal) across lymphoma subtypes, though monoclonal elevated FLC (FLC ratio abnormal) was common in MCL and the post-follicular lymphomas. Elevated FLC was associated with inferior EFS in all lymphomas combined (monoclonal HR=1.92, 95% CI:1.44-5.55, polyclonal HR=1.38, 95% CI:1.09-1.74); this association remained consistent in most subtypes (see table). In addition, elevated FLC was associated with poor EFS in MCL (monoclonal) and Hodgkin lymphoma (HL; polyclonal). Elevated FLC was also significantly associated with OS in HL (polyclonal HR=6.24, 95% CI 2.44–15.9), FL (polyclonal HR=5.85, 95% CI 2.62–13.0), post follicular lymphomas (polyclonal HR=4.16, 95% CI 1.17–14.8), as well as for all lymphomas combined (monoclonal HR=2.24, 95% CI 1.52–3.29, polyclonal HR=2.33, 95% CI 1.74–3.11). Conclusions: A significant percentage of lymphoma patients have elevated FLC. Our previous discovery of elevated FLC predicting poor outcome in DLBCL was confirmed in a large, independent dataset. Prevalence and type of elevated FLC (monoclonal vs. polyclonal) varies by lymphoma subtype. Elevated monoclonal and polyclonal FLC is associated with poor outcome broadly in lymphoma, as well as specifically for a number of lymphoma subtypes, supporting FLC as a potentially useful prognostic biomarker in many lymphoma subtypes. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 4168 Background: Primary Pulmonary MALT lymphoma represents 15–20% of Extranodal Marginal Zone Lymphomas of Mucosa Associated Lymphoid Tissue (MALT). In contrast to the more common gastric MALT lymphoma, natural history, prognosis and treatment outcomes for primary pulmonary MALT lymphoma are not well defined. Herein, we report a single institution experience. Methods: Consecutive patients with primary pulmonary MALT lymphoma registered in the Mayo Clinic Lymphoma Database, which includes all consenting patients with lymphoma seen at Mayo Clinic Rochester, were reviewed for clinical features, treatment outcome progression free survival (PFS) and overall survival (OS). The pathology for all patients was centrally reviewed by hematopathologist and the diagnoses were based on WHO lymphoma classification criteria. PFS and OS were assessed using the Kaplan–Meier method and the Cox proportional hazard model was used to assess the impact of variables on PFS and OS. Results: Between December 1986 and June of 2009, ninety-seven patients with primary pulmonary MALT lymphoma were enrolled. The median age at diagnosis was 63 years (range 31–87). There were 43 (44%) males. The initial presentation was a unilateral pulmonary lesion (n=47, 48%), bilateral pulmonary lesions (n=41, 42%), and pulmonary lesion with intrathoracic lymphadenopathy (n= 4, 4%). Bone marrow involvement and presence of B symptoms were 4, 4% and 5, 5%, respectively. International Prognostic Index (IPI) was 0–1, 2–3 and 4–5 in 69, 25 and 1 patient(s) respectively. The median follow-up was 10.4 years. The estimated median OS was 13. 6 years and the median PFS was 5.5 years (Figure). In a multivariate analysis, age >60 (p=0.02) and ECOG PS>2 (p=0.01) were associated with shortened survival. The IPI and age adjusted IPI were not predictive of overall survival. The treatment outcomes for the most common treatment modalities are summarized in the Table below. The median PFS of the 38% of patients who had a complete surgical resection was excellent at 11.2 years; whereas for observed patients with residual disease after biopsy was 3.2 years. Only 8 patients received single agent rituximan with relatively low response rate. Summary: The prognosis of primary pulmonary MALT lymphoma is favorable, with a median survival of over 13 years. In patients with resectable disease, surgery alone is associated with excellent disease control. Further prospective studies are needed to define the optimal treatment of primary pulmonary MALT lymphoma. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 287 Purpose: Farnesyltransferases are key cellular enzymes involved in the prenylation of proteins. Prenylated proteins are important for malignant cell growth. The purpose of this phase II study (NCT00082888) was to assess tumor response and toxicity associated with the oral farnesyltransferase inhibitor tipifarnib (R115777, Johnson and Johnson) in patients with relapsed aggressive, indolent, or uncommon lymphoma. The uncommon group included low incidence lymphoma types such as Hodgkin lymphoma (HL) and T-cell non-Hodgkin lymphoma- cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL). Patients and Methods: Patients with relapsed or refractory non-Hodgkin (NHL) or Hodgkin (HL) were eligible if they had measurable disease, performance status ≤2, platelet count ≥75,000 × 10(6)/L, an absolute neutrophil count ≥1000 × 10(6)/L and a creatinine ≤2 × upper limit of normal. Patients initially received tipifarnib 300 mg twice daily, days 1–21 every 28 days. The trial was conducted by the University of Iowa/Mayo Clinic Lymphoma SPORE. Results: Ninety-three patients with lymphoma (42 aggressive, 15 indolent, and 36 uncommon) enrolled in the trial between March 2004 and November 2008. The median age was 62 years (range, 18–91). The median number of prior therapies was 5 (range, 1–17). The overall response rate (ORR) was 20% (19/93) with 6% (6/93) complete responses (CR) and 14% (13/93) partial responses (PR). The ORR was 17%, 7%, and 31% for the aggressive, indolent, and uncommon groups, respectively (Table). Among the 19 responders were 7 diffuse large B-cell lymphoma (DLBCL), 7 T-cell NHL, 1 follicular grade II, and 4 HL. The overall median response duration for the 19 responders was 7.5 months (mean, 12.8; range, 1.8 – 48.1 months). The median response duration was 11.3 months (mean, 10.1; range, 1.8 – 18.5 months), 2 months, and 7.5 months (mean, 15.5; range, 1.9 – 48.1 months) for the aggressive (7), indolent (1), and uncommon (11) groups, respectively. Five patients in the uncommon group are still receiving treatment with a range of treatment duration between 25 – 60+ months. Among the 5 still receiving treatment 4 responded and 1 is stable. The range of response duration is 15.4, 17.7, 43.1, and 48.1 months. These five patients (2 with HL, 1 anaplastic large cell cutaneous, and 2 PTCL) are currently receiving doses of 400 (1), 200 (2), and 100 (2) mg twice daily. The median time to progression for all patients was 3.6 months (95% CI: 2.1 – 4.5 months). The grade 3,4 toxicities observed were primarily fatigue (10%) and reversible myelosuppression with 11% anemia, 37% neutropenia, and 32% thrombocytopenia. Correlative studies demonstrated tipifarnib-induced upregulation of Bim, a marker of tipifarnib action in lymphoma cell lines, in 7 of 9 paired lymphoma biopsies. Conclusions: Tipifarnib has activity in lymphoma, with responses in patients with heavily pretreated DLBCL, HL and T-cell types, but little activity in follicular NHL. This agent has an excellent toxicity profile and targets a novel pathway. Further studies in combination with other agents are warranted for patients with DLBCL, HL or T-cell NHL. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 137 Background: FDG-PET/CT after 2–4 cycles of chemotherapy has been shown to be predictive of outcome in patients with aggressive lymphoma. This multicenter NCCTG phase II study was carried out to assess efficacy of ER-CHOP in newly diagnosed DLBCL; functional response as measured by FDG-PET/CT was done after 2 cycles and after 6 cycles of therapy. Methods: Patients received immunochemotherapy on the following schedule: epratuzumab 360 mg/m2, rituximab 375 mg/m2, and standard dose CHOP every 3 weeks for 6 cycles. FDG-PET/CT was done after 2 cycles and again after 6 cycles of therapy. All PET scans were centrally reviewed by an expert in nuclear medicine who was blinded to the outcome of the patients. Results: 107 patients were accrued from Feb 2006 to Aug 2007. 27 patients were ineligible resulting in 80 eligible patients. Baseline patient characteristics for the eligible patients included median age 60 (range 21–82); 56% were male. 80% had advanced stage; 73% had an elevated LDH. Performance score was 0–1 in 71 pts and 2–3 in 9 pts. IPI was 0–1 in 18 pts (23%), 2 in 22 pts (28%), 3 in 29 pts (36%) and 4–5 in 11 pts (14%). PET scans were available on 76 patients (95%); 3 patients completed treatment but scans were unavailable and 1 died prior to cycle 2 PET. The PET CR rate after 2 cycles was 79%. The PET CR rate after 6 cycles was 90%. Using an intent to treat (ITT) analysis, 67 patients (87%) achieved PET CR of which 61 (79%) also completed all 6 cycles of treatment. Based on interim PET after 2 cycles, the EFS at 24 months (EFS24) was 73% for the PET negative patients vs 60% for the PET positive patients (p=0.25); OS at 24 months (OS24) was 83% vs 73% for the PET negative and positive pts, respectively (p=0.17). In comparison, EFS24 for patients with a negative PET after 6 cycles was 80% vs 57% for those with a positive PET (p=0.11); OS24 was 92% vs 57%, respectively (p=0.01). In intent to treat (ITT) analysis, patients that achieved a functional CR had improved overall survival (OS24 = 84%) and event free survival (EFS24 = 74%) compared to patients that failed to achieve a functional CR (OS24 = 50%, EFS24 = 40%, p=0.01 and p=0.006 respectively). Conclusions: ER-CHOP every 21 days × 6 cycles results in a functional CR rate of 87%. Early PET scan during therapy does not significantly predict outcome. Achievement of PET negativity by completion of therapy is associated with a good outcome Disclosures: No relevant conflicts of interest to declare.

Abstract Background: A previous trial of 2-CDA as a single agent for therapy of mantle cell lymphoma demonstrated this agent to be efficacious with an overall response rate of 81% (31% complete responses) (Blood 1999 Nov 15; 94:660a). A phase II study of the addition of rituximab to 2-CDA was conducted by the North Central Cancer Treatment Group based on improved outcomes achieved by the addition of rituximab to other regimens active in MCL. Methods: This one-stage phase II study was designed to determine the complete response (CR) or complete response/unconfirmed (CRu) rate. Central pathology confirmation of cyclin D1 positive mantle cell lymphoma was required. No previous therapy for lymphoma was allowed, with the exception of splenectomy. The schedule was rituximab 375 mg/m2 IV day 1; 2-CDA 5 mg/m2/d IV days 1–5 of a 4-week cycle. After 2 of the first 6 patients developed grade 4 neutropenia, subsequent patients received either pegfilgrastim or filgrastim support. Patients received 2–6 cycles of therapy, depending on response. Patients were required to achieve at least a PR after 2 cycles of therapy to continue on protocol therapy. Results: Patient characteristics of all 29 eligible pts: median age: 70 (range: 41–86); 21 male, 8 female; PS 0 (55.2%), PS 1 (41.4%), PS 2 (3.5%); stage II (6.9%), stage III (3.5%), stage IV (89.7%); prior splenectomy (20.7%). The only grade 4 adverse events occurring more than once were neutropenia (24.1%) and leucopenia (6.9%). One patient died of cerebral ischemia in the setting of pneumonia without neutropenia. Fifteen (51.7%; 95% CI: 32.5–70.6%) pts achieved a CR; only one has relapsed to date (665 days after starting therapy). Four additional pts achieved a PR. Ten pts have progressed with 4 pts progressing early at 17, 45, 46, and 71 days (two of whom have died). Ten pts (34.0%) went on to receive further therapy off study, 5 in less than a PR after 2 cycles, 2 in PR after study therapy, and 1 who went off study for a rash. Fourteen pts (48.3%) have progressed or gone on to receive additional therapy off study. At last contact, 26 (89.7%) were alive (median follow-up 14.3 months; range: 6–34). One year survival rate is 89.3% (95% CI: 78.5–100). Conclusions: Rituximab and cladribine were well tolerated for the treatment of MCL in a group of elderly patients. The response rate may have been underestimated due to the study design, which required at least a PR after 2 cycles to continue therapy. Despite this, 52% achieved a complete remission. Complete remissions attained with this regimen appear to be durable, with a single relapse to date among 15 patients achieving CR.

Abstract Abstract 1540 Background: Diffuse Large B-cell Lymphoma (DLBCL) is the most common lymphoma in the western world. Outcomes have improved with the standard initial therapy of rituximab and anthracyline based chemotherapy (immunochemotherapy). However, 20–40% of patients will either fail to achieve remission or relapse following initial immunochemotherapy. Most relapses occur early, and long-term outcome of relapsed/refractory patients is generally poor despite salvage regimens and stem cell transplant. Traditionally, studies for DLBCL have been evaluated using progression-free and/or overall survival. However, the event rate in DLBCL slows significantly approximately 12–18 months after diagnosis, and late events are often due to competing (non-DLBCL related) risks, especially in older patients. Here we examine outcome of DLBCL patients based on their event status at 12 months. Methods: Newly diagnosed DLBCL patients were prospectively enrolled in the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER). Clinical data were abstracted from medical records using a standard protocol. Patients were actively followed for events (progression, re-treatment, or death due to any cause) and overall survival (OS). Event-free status at 12 months after diagnosis (EFS12) was assessed as a dichotomous variable. Cause of death was determined by medical record and death certificate review using prospectively determined definitions. Expected survival was based on age and sex matched survival using the Minnesota population death rates. Confirmation cohorts were from a Lyon, France hospital based registry and NCCTG clinical trial N0489. Results: 680 patients with newly diagnosed DLBCL and treated with rituximab + anthracycline based chemotherapy were enrolled in the MER from 2002 to 2009. The median age was 62 years (range 18–92). 53% were male. At a median follow-up of 59 months (range 8–116), 266 patients (39%) had an event and 188 patients (28%) died. 162 patients (24%) had an event in the first 12 months after diagnosis, comprising 60% of all events. Patients with an event in the first 12 months had poor survival with death almost exclusively due to disease (Figures 1a, 2a). In contrast, patients who were event-free at 12 months had comparable survival to the age and sex matched general population (Figure 2b) and were more likely to die of other causes than DLBCL (Figure 1b). Overall survival rates by EFS12 status were validated in patients from a French hospital-based registry (N=265) and the NCCTG N0489 clinical trial (N=87) with additional replication studies underway. Conclusions: DLBCL patients who are event-free at 12 months after diagnosis have an excellent prognosis with an overall survival similar to that of an age- and sex- matched general population and are more likely to die of other causes than DLBCL. This finding has implications for clinical management, new clinical trials, and follow-up testing in this patient population. In contrast, patients with an event within the first 12 months after diagnosis have a poor prognosis with almost all deaths secondary to DLBCL. EFS status at 12 months identifies patients with poor outcomes due to disease. This can be utilized as an endpoint in biologic studies and clinical trials to address early treatment failures. EFS status at 12 months should be incorporated into prognostic models to identify high risk patients in newly diagnosed DLBCL. Disclosures: No relevant conflicts of interest to declare.

Abstract Introduction: AL amyloidosis is a very heterogeneous disease. Prognosis is a function of organ tropism, extent of organ damage, and ability of tissues to heal, the last of which relates both to hematologic response and intrinsic toxicity of the light chain. Using mass spectroscopy (MS) technology, we are able to distinguish immunoglobulin light chain variable gene family (IGVL) usage on clinical samples. The goal of this study was to evaluate if IGVL usage impacts patient outcomes in patients with light chain amyloidosis (AL). Methods: IGVL usage was determined by mass spectroscopy (MS) of amyloid in clinical tissue specimens of Mayo Clinic patients. Specimens were from fat pad (n=257), bone marrow (n=172), myocardium (n=113), gastrointestinal (n=58), kidney (n=20), lung (n=15), and nerve (n=5). For those cases for which the IGVL could not be identified--not otherwise specified (NOS)—but constant region could be identified as lambda or kappa, we assume that the amyloid consisted primarily of immunoglobulin light chain gene constant regions or variable genes with somatic mutations making them uninterpretable to our matching algorithms. The medical records from these 700 patients were abstracted for relevant clinical and laboratory data. Results: The baseline characteristics of patients are shown in table 1. Three hundred and thirty-two patients have died with a median follow-up of surviving patients of 38 months. The estimated median survival for the entire population is 59 months. Out of 700 patients, 214 (31%) achieved a CR or a VGPR, 432 (62%) were not evaluable (NE) for hematologic or organ response, and 54 (8%) achieved a PR or did not respond (NR). The distribution of IGVL cases is shown in table 2. Overall survival (OS) for the whole group was not different across different IGVLs on univariate analysis, but when corrected for hematologic response, outcomes differed significantly based on IGVL. Patients could be further assembled into two groups, based on risk for death on univariate analyses: an IGVL high risk, which included KV1, LV1, LV2, LV3, and LV6; and low risk, which included all other cases (Figure). In a multivariate model that included level of hematologic response (CR/VGPR versus PR/NR/NE) and IGVL, IGVL family was independently associated with overall survival (RR=1.5 (95% CI 1.2-1.9, p=0.008). The risk ratio for CR/VGPR was 0.28 (95% CI 0.20-0.38, p<0.0001). This effect persisted when either the Mayo 2006 or the 2012 staging system was included in the multivariate. Conclusion: IGVL usage appears to have prognostic significance in patients who have not achieved VGPR or better to initial chemotherapy. Table 1. Baseline characteristics of patients N= 700 Age 63 (32-94) Male, (%) 447 (64%) Biopsy site Solid organ/Soft tissue 271 (39%) Fat pad 257 (37%) Bone Marrow 172 (25%) Organ involvement Cardiac 432 (62%) Renal 346 (49%) Gastrointestinal 168 (24%) Liver 56 (8%) Nerve 107 (15%) Lung 42 (6%) Soft Tissue 92 (13%) Organs involved 1 321 (46%) 2 228 (33%) ≥3 151 (22%) Laboratory characteristics NTBNP, pg/ml 2547 (11.3-70000) Troponin, ng/ml 0.03 (0.001-0.84) dFLC, mg/dl 26 (0.04-2330) Cardiac Stage 1 59 (18%) 2 125 (38%) 3 144 (44%) Table 2. Variable region family distribution. Light Chain N=700 N (%) KV1 107 (15%) KV2 3 (0.4%) KV3 17 (2%) KV4 25 (4%) KV6 1 (0.1%) LV1 85 (12%) LV2 64 (9%) LV3 118 (17%) LV4 3 (0.4%) LV6 97 (14%) LV8 1 (0.1%) LV9 1 (0.1%) Kappa NOS1 34 (4%) Lambda NOS1 140 (19%) Heavy chain amyloidosis 4 (0.6%) 1 No IGVL family could be identified Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Abstract Peripheral T- and NK-cell lymphomas (PTCLs) are fatal in the majority of patients, and conventional chemotherapy is minimally effective. Targeted inhibition of tyrosine kinases (TKs) might be a useful treatment strategy, but TK overexpression by PTCLs has not been well characterized (except ALK). Recently a novel translocation t(5;9) fusing the ITK and SYK genes was reported in a subset of unspecified-type PTCLs, associated with high SYK gene expression and Syk protein positivity. Syk is a non-receptor TK important in immunoreceptor signal transduction, providing proliferation and survival signals in a variety of hematopoietic cells. Syk is absent or expressed at very low levels in most normal post-thymic T cells, where this signal transduction role is fulfilled by ZAP70. Since Syk TK inhibitors are now in clinical trials for other diseases, we sought to determine the incidence of t(5;9) and Syk overexpression in PTCL. Tissue microarrays were constructed using triplicate cores from paraffin-embedded tissue blocks. Cases were studied using fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). Additional studies were performed using flow cytometry and Western blot. There were 141 PTCLs, including 35 angioimmunoblastic, 66 unspecified, 21 anaplastic large cell, 2 enteropathy-associated, 5 hepatosplenic, 5 extranodal NK/T, and 7 other. No evidence of t(5;9) was identified by FISH in 86 informative cases. Normal T-cell subsets from peripheral blood, spleen, and lymph node were negative for Syk by IHC, flow cytometry, and Western blot. Syk was positive by immunohistochemistry in 133 of 141 (94%) PTCLs. All 8 Syk negative cases were extranodal, cytotoxic PTCLs. Western blot on frozen tissue correlated with IHC results in paraffin. All 4 Syk-positive cases tested showed phosphorylation of tyrosine residues 525/526, known to be required for Syk activation. We conclude that Syk is overexpressed in most PTCLs, including the vast majority of nodal cases. Syk may substitute for ZAP70 in these tumors and provide ongoing proliferation and survival signaling. The overexpression of Syk and phosphorylation of its Y525/526 residues suggest Syk may be a suitable target for pharmacologic TK inhibition as a treatment option for patients with PTCL.

Abstract Abstract 3661 Objective: We conducted this trial to determine the maximum tolerated dose (MTD) and schedule of temsirolimus added to an established regimen comprised of rituximab and cladribine for the initial treatment of mantle cell lymphoma and to generate preliminary information on the toxicity and efficacy of this combination. Methods: A standard phase I cohort of 3 study design was utilized. MTD was defined as the dose level below the lowest dose that induces dose-limiting toxicity (DLT) in at least one-third of patients (at least 2 of a maximum of 6 new patients). DLT was defined as grade 4 ANC (<500) for ≥5 days, grade 4 ANC (<500) associated with fever (>100.5 F) and/or active infection, PLT <25,000, grade 4 infection, or ≥grade 3 non-hematologic toxicity during the first cycle of therapy as per NCI Common Terminology Criteria for Adverse Events v3.0. The fixed doses of rituximab and cladribine were 375 mg/m2 IV day 1 and 5 mg/m2/d IV days 1–5 of a 28 day cycle, respectively, as previously published. There were 5 planned temsirolimus IV dose levels: 15 mg day 1; 25 mg day 1; 25 mg days 1 and 15; 25 mg days 1,8 and 15; and 25 mg days 1,8,15, and 22. The fifth dose level is as previously published in combination with rituximab. Results: A total of 17 patients were treated: 3 each at dose levels 1–4 and 5 at dose level 5 (25 mg temsirolimus days 1,8,15, and 22). The median age was 75 years (52–86). There were 11 males and 6 females. At presentation 88% had stage IV disease, and 94% had extranodal disease. MIPI scores were low in 6% (1 patient), intermediate in 59% (10 patients), and high in 35% (6 patients). There was a single DLT recorded at dose level 3 based on the initial DLT criteria, though this cytokine release syndrome was clearly rituximab related, and occurred prior to the first dose of temsirolimus. Five patients were treated at the highest planned temsirolimus dose level (25 mg days 1,8,15, and 22) with no DLT observed. No further dose escalation was planned, and this level was determined to be tolerated, though higher levels may be tolerable. All patients were evaluable for adverse events. Hematologic toxicity was frequent, with grade 3 anemia in 12% of patients, grade 3 thrombocytopenia in 35%, grade 4 thrombocytopenia in 30%, grade 4 lymphopenia in 47%, grade 3 neutropenia in 24%, and grade 4 neutropenia in 18% of patients. There were 3 thrombotic episodes, 2 of which were attributed to therapy, and 3 episodes of pneumonitis. The overall response rate was 94% with 53% CR and 41% PR. The median progression free survival was 18.7 months. Conclusions: Temsirolimus 25 mg IV weekly may be safely added to rituximab and cladribine at 375 mg/m2 IV day 1 and 5 mg/m2/d IV days 1–5 of a 28 day cycle, respectively. This regimen had promising preliminary activity in an elderly cohort of patients with mantle cell lymphoma. Disclosures: Off Label Use: Temsirolimus for mantle cell lymphoma.

Abstract Abstract 1665 Poster Board I-691 Mantle cell lymphoma (MCL) is an aggressive, incurable B-cell malignancy that represents approximately 6% of lymphoma cases. Patients with MCL who relapse after conventional therapy or stem cell transplantation have a poor prognosis and are candidates for treatment with novel agents. The characteristic feature of MCL is overexpression of cyclin D1. Cyclin D1 is under the control of the phosphatidylinositol-3 kinase signal-transduction pathway and is downstream of the mammalian target of rapamycin kinase (mTOR). We have previously shown that temsirolimus (CCI-779), a dihydroester of the selective mTOR inhibitor rapamycin, is an active antitumor agent in MCL. In previous phase 2 trials of temsirolimus as a single agent, we observed a 40% overall response rate (ORR) with a median duration of response (DR) of 6 months in patients with relapsed or refractory disease (J Clin Oncol 23:5347-56, 2005; Cancer 113:508-514, 2008). Due to the fact that rituximab has improved the response rate and overall outcome of lymphoma patients when combined with chemotherapy, we tested the efficacy and toxicity of temsirolimus in combination with rituximab in patients with MCL. Eligible patients with confirmed relapsed or refractory MCL based on morphologic and phenotypic features received temsirolimus 25 mg intravenously every week and four weekly doses of rituximab with the first cycle and then one dose of rituximab every other cycle. Patients with a tumor response after six cycles were eligible to continue treatment for a total of 12 cycles or two cycles after complete remission, and were then observed without maintenance. Seventy-one patients were enrolled between May 2005 and March 2009. The median age was 67 years (range, 44 to 86 years), with 51 males and 20 females enrolled. Patients had received a median of two prior therapies (range, 1-9), 31% had received a prior stem cell transplant and 28% were rituximab refractory. The ORR was 48% (34/71 patients) with 20% (14/71) complete responses and 28% (20/71) partial responses. The median DR was 9.5 months (95% CI, 4.5 to 11.3 months). The median DR in the rituximab sensitive patients was 9.5 months (CI: 4.5-11.6) and 7.15 months (CI: 4.1-11.3) in the rituximab refractory patients (p= 0.73). While the combination was generally well tolerated, 12 patients experienced grade 4 toxicity and 2 patients died while on therapy – both from progressive disease. Hematologic toxicities were the most common, with 5 patients having grade 4 thrombocytopenia and 3 having grade 4 neutropenia. This study demonstrates that temsirolimus in combination with rituximab is well tolerated and has substantial antitumor activity in relapsed MCL. Further comparative studies of this combination in MCL are therefore warranted. Disclosures Witzig: Wyeth: Patents & Royalties.