Motexafin Gadolinium (MGd) Has Clinical Activity in Relapsed/Refractory Low Grade Lymphomas (LG) and Relapsed/Refractory Chronic Lymphocytic Leukemia (CLL).

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4758-4758
Author(s):  
Brad S. Kahl ◽  
Ranjana Advani ◽  
Neil Kay ◽  
Izidore S. Lossos ◽  
Andrew Evens ◽  
...  

Motexafin gadolinium (MGd, Xcytrin®) is a novel anti-cancer drug that selectively concentrates in cancer cells and disrupts redox dependent pathways by targeting oxidative stress related proteins such as thioredoxin reductase and metallothioneins. MGd has been shown to generate reactive oxygen species and induce apoptosis in tumor cells. We initiated a study to evaluate the safety and efficacy of MGd in two B-cell malignancies, relapsed/refractory LG and relapsed/refractory CLL or CLL/small lymphocytic lymphoma (CLL/SLL). MGd was given intravenously (IV) at 6mg/kg/day for 3 days q 2 weeks for LG and 5mg/kg/day for 10 days q 3 weeks for CLL/SLL. Ten patients (pts) with LG (2 grade 1, 5 grade 2, 1 grade 3 follicular, 2 marginal zone), 2 pts with CLL/SLL and 1 pt with CLL have been enrolled. Median age was 64.5 yrs (range 44–77), median prior treatment regimens was 3.5 (range 1–6) and median time from diagnosis to treatment was 52 mo. Many LG pts had failed prior aggressive treatment regimens including: CHOP (4), ICE (1), HyperCVAD(1), auto-bone marrow transplant (1); all failed rituxamab and 6 failed Zevalin. CLL/SLL and CLL pts had failed rituxamab (3), fludarabine (2), and R-CHOP (1). MGd related adverse events included skin and urine discoloration (6 and 4 pts), diarrhea, nausea, vesiculobullous rash, peripheral neuropathy (3 pts each). MGd related ≥gr 3 adverse events included skin rash (3 pts), fatigue, neuropathy, photosensitivity (1 pt each). Importantly, no MGd-related myelosuppression was observed. In 12 evaluable pts, there have been three PRs of 2+, 5+ and 8 months duration (2 follicular, 1 CLL). Two pts had SD (follicular, SLL) one of these had resolution of lymphoma related autoimmune hemolytic anemia. Responses occurred after ≤2 cycles of therapy and were seen in patients after extensive prior treatment (mean 4.3 prior regimens, range 3–7). MGd is a non-myelosuppressive drug with single agent activity in LG and CLL/SLL.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2503-2503 ◽  
Author(s):  
John C. Byrd ◽  
Susan O’Brien ◽  
Ian Flinn ◽  
Thomas J. Kipps ◽  
Mark A. Weiss ◽  
...  

Abstract The CD23 antigen is expressed at high density on the cell surface of certain B-cell malignancies, including chronic lymphocytic leukemia (CLL). Lumiliximab (L-mab), a macaque-human chimeric anti-CD23 monoclonal antibody, has been reported to have antitumor activity against CLL in preclinical studies. In this Phase I multicenter study, the safety, efficacy, and pharmacokinetics of single-agent L-mab were evaluated in 46 patients with relapsed or refractory CLL. Therapy consisted of intravenous L-mab given as 6 regimens: (1) 125 mg/m2/wk for 4 weeks; (2) 250 mg/m2/wk for 4 weeks; (3) 375 mg/m2/wk for 4 weeks; (4) 500 mg/m2/wk for 4 weeks; (5) 500 mg/m2 for 3 doses during Week 1, then 500 mg/m2/wk during Weeks 2 to 4; and (6) 500 mg/m2 three times a week for 4 weeks. Patient characteristics were as follows: median age of 62 years (range 47 to 80 years), 93% Caucasian, 72% male, 54% fludarabine-refractory, 48% Rai stage III/IV, and 78% WHO Performance Status 1. At study entry, patients had progressive CLL after 1 to 13 prior treatment regimens (median = 4 prior regimens). Antibody infusions, administered over 2 hours in an outpatient setting, were well tolerated. Study-related adverse events (probable, possible, or unknown relationship to study treatment) were reported in 40 of 46 patients (87%). The majority of events were Grade 1 or 2; the most common were headache, constipation, nausea, and cough. Grade 3 or 4 study-related adverse events were reported in 7 of 46 patients (15%) and included neutropenia and dyspnea. Evidence of clinical activity consisted of reductions in absolute lymphocyte counts (ALC) and lymphadenopathy. Decreases in ALC were observed in 42 of 46 (91%) patients, and decreases ≥ 50% were observed in 11 of 40 (28%) patients enrolled at 375 mg/m2/week or higher. Of 37 patients evaluated for change in lymphadenopathy, reductions were observed in 22 (59%). Flow cytometry revealed that L-mab saturated CD23 sites on CLL cells at doses above 375 mg/m2/week without down regulating CD23 expression. These results suggest that single-agent L-mab can be administered safely with evidence of clinical activity in patients with heavily pretreated CLL. Ongoing clinical studies are assessing the potential of L-mab in combination with rituximab and fludarabine-based chemotherapy.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2638-2638 ◽  
Author(s):  
Anas Younes ◽  
Barbara Pro ◽  
Jorge Romaguera ◽  
Nam Dang

Abstract The proteasome inhibitor bortezomib has demonstrated clinical activity in patients with multiple myeloma and different types of non-Hodgkin’s lymphoma. Its activity in patients with Hodgkin’s disease (HD) is unknown. We have recently reported that bortezomib had a significant activity against HD-derived cell lines in vitro (Zheng et al, Clin Cancer Res 2004), In four HD-derived cell lines, bortezomib induced cell cycle arrest and apoptosis in a dose and time dependent manner, irrespective of IkB gene mutations. Furthermore, bortezomib enhanced the activity of chemotherapy and TRAIL in these cell lines. Based on these encouraging preclinical results, we initiated a pilot study of single agent bortezomib in patients with relapsed classical HD. Eligibility: (1) relapsed classical HD with a measurable disease (2) At least 2 prior treatment regimens; (3) Patients with prior autologous stem cell transplant (ASCT) are eligible (4) platelet counts > 50,000/uL and ANC counts of > 1,500/uL (5) no HIV infection, or CNS involvement with HD, (6) bilirubin < 2mg/dL and creatinine < 2.5 mg/dL. Patients were treated with 1.3 mg/m2 bortezomib intravenously on days 1, 4, 8, 11 of 21-day cycles in an outpatient setting. Treatment was delayed if the Platelet counts on the day of therapy was < 30,000/mm3. After 3 cycles of bortezomib therapy patients were evaluated for treatment response. If there was no evidence of disease progression after 3 cycles of therapy, patients were allowed to receive a maximum of 6 cycles. To date, 11 patients are enrolled (6 men and 5 women), with a median age of 28 years (range: 21 to 68 years). All patients were heavily pretreated, with a median number of 5 prior treatment regimens (range 2 to 7 regimens), and all patients have previously failed ASCT. The median pretreatment platelet count was 126, 000/uL (range 66,000 – 339,000/uL). All patients received at least one dose of bortezomib and are evaluable for treatment toxicity. Treatment was reasonably well tolerated with the majority of toxic effects were of grade 1 and 2. Two patients had grade 3 dyspnea and one patient had grade 3 neutropenic fever. Progressive thrombocytopenia was the most common hematologic toxicity, which frequently caused delays in therapy. Nadir platelet count below 30,000/uL was observed in 3/11 patients during the first cycle, in 4/10 during the second cycle, and in 4/6 during the third cycle. Nadir ANC below 1000/uL was observed in 1/11 pts during cycle 1, in 2/10 during cycle 2, and in 1/6 during cycle 3. Eight patients completed the planned 3 cycles and are evaluable for treatment response. One patient achieved a partial remission and one had a minimal response. Our preliminary data demonstrate encouraging clinical activity of bortezomib in this heavily pretreated patients with classical HD, and warrants studying bortezomib in less heavily pretreated patients either as a single agent or in combination with chemotherapy.


Blood ◽  
2009 ◽  
Vol 114 (4) ◽  
pp. 772-778 ◽  
Author(s):  
Paul Richardson ◽  
Sundar Jagannath ◽  
Mohamad Hussein ◽  
James Berenson ◽  
Seema Singhal ◽  
...  

Abstract Lenalidomide plus dexamethasone is effective for the treatment of relapsed and refractory multiple myeloma (MM); however, toxicities from dexamethasone can be dose limiting. We evaluated the efficacy and safety of lenalidomide monotherapy in patients with relapsed and refractory MM. Patients (N = 222) received lenalidomide 30 mg/day once daily (days 1-21 every 28 days) until disease progression or intolerance. Response, progression-free survival (PFS), overall survival (OS), time to progression (TTP), and safety were assessed. Overall, 67% of patients had received 3 or more prior treatment regimens. Partial response or better was reported in 26% of patients, with minimal response 18%. There was no difference between patients who had received 2 or fewer versus 3 or more prior treatment regimens (45% vs 44%, respectively). Median values for TTP, PFS, and OS were 5.2, 4.9, and 23.2 months, respectively. The most common grade 3 or 4 adverse events were neutropenia (60%), thrombocytopenia (39%), and anemia (20%), which proved manageable with dose reduction. Grade 3 or 4 febrile neutropenia occurred in 4% of patients. Lenalidomide monotherapy is active in relapsed and refractory MM with acceptable toxicities. These data support treatment with single-agent lenalidomide, as well as its use in steroid-sparing combination approaches. The study is registered at http://www.clinicaltrials.gov as NCT00065351.


Blood ◽  
1999 ◽  
Vol 94 (7) ◽  
pp. 2217-2224 ◽  
Author(s):  
U. Winkler ◽  
M. Jensen ◽  
O. Manzke ◽  
H. Schulz ◽  
V. Diehl ◽  
...  

Eleven patients with relapsed fludarabine-resistant B-cell chronic lymphocytic leukemia (CLL) or leukemic variants of low-grade B-cell non-Hodgkin’s lymphoma (NHL) were treated with the chimeric monoclonal anti-CD20 antibody rituximab (IDEC-C2B8). Peripheral lymphocyte counts at baseline varied from 0.2 to 294.3 × 109/L. During the first rituximab infusion, patients with lymphocyte counts exceeding 50.0 × 109/L experienced a severe cytokine-release syndrome. Ninety minutes after onset of the infusion, serum levels of tumor necrosis factor- (TNF-) and interleukin-6 (IL-6) peaked in all patients. Elevated cytokine levels during treatment were associated with clinical symptoms, including fever, chills, nausea, vomiting, hypotension, and dyspnea. Lymphocyte and platelet counts dropped to 50% to 75% of baseline values within 12 hours after the onset of the infusion. Simultaneously, there was a 5-fold to 10-fold increase of liver enzymes, d-dimers, and lactate dehydrogenase (LDH), as well as a prolongation of the prothrombin time. Frequency and severity of first-dose adverse events were dependent on the number of circulating tumor cells at baseline: patients with lymphocyte counts greater than 50.0 × 109/L experienced significantly more adverse events of National Cancer Institute (NCI) grade III/IV toxicity than patients with less than 50.0 × 109/L peripheral tumor cells (P= .0017). Due to massive side effects in the first patient treated with 375 mg/m2 in 1 day, a fractionated dosing schedule was used in all subsequent patients with application of 50 mg rituximab on day 1, 150 mg on day 2, and the rest of the 375 mg/m2 dose on day 3. While the patient with the leukemic variant of the mantle-cell NHL achieved a complete remission (9 months+) after treatment with 4 × 375 mg/m2 rituximab, efficacy in patients with relapsed fludarabine-resistant B-CLL was poor: 1 partial remission, 7 cases of stable disease, and 1 progressive disease were observed in 9 evaluable patients with CLL. On the basis of these data, different infusion schedules and/or combination regimens with chemotherapeutic drugs to reduce tumor burden before treatment with rituximab will have to be evaluated.


2010 ◽  
Vol 28 (18) ◽  
pp. 3015-3022 ◽  
Author(s):  
Wei-Gang Tong ◽  
Rong Chen ◽  
William Plunkett ◽  
David Siegel ◽  
Rajni Sinha ◽  
...  

Purpose SNS-032 is a highly selective and potent inhibitor of cyclin-dependent kinases (Cdks) 2, 7, and 9, with in vitro growth inhibitory effects and ability to induce apoptosis in malignant B cells. A phase I dose-escalation study of SNS-032 was conducted to evaluate safety, pharmacokinetics, biomarkers of mechanism-based pharmacodynamic (PD) activity, and clinical efficacy. Patients and Methods Parallel cohorts of previously treated patients with chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) received SNS-032 as a loading dose followed by 6-hour infusion weekly for 3 weeks of each 4-week course. Results There were 19 patients with CLL and 18 with MM treated. Tumor lysis syndrome was the dose-limiting toxicity (DLT) for CLL, the maximum-tolerated dose (MTD) was 75 mg/m2, and the most frequent grade 3 to 4 toxicity was myelosuppression. One patient with CLL had more than 50% reduction in measurable disease without improvement in hematologic parameters. Another patient with low tumor burden had stable disease for four courses. For patients with MM, no DLT was observed and MTD was not identified at up to 75 mg/m2, owing to early study closure. Two patients with MM had stable disease and one had normalization of spleen size with treatment. Biomarker analyses demonstrated mechanism-based PD activity with inhibition of Cdk7 and Cdk9, decreases in Mcl-1 and XIAP expression level, and associated CLL cell apoptosis. Conclusion SNS-032 demonstrated mechanism-based target modulation and limited clinical activity in heavily pretreated patients with CLL and MM. Further single-agent, PD-based, dose and schedule modification is warranted to maximize clinical efficacy.


2009 ◽  
Vol 27 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Brian M. Wolpin ◽  
Aram F. Hezel ◽  
Thomas Abrams ◽  
Lawrence S. Blaszkowsky ◽  
Jeffrey A. Meyerhardt ◽  
...  

PurposeThe PI3K/Akt/mTOR pathway is activated in the majority of pancreatic cancers, and inhibition of this pathway has antitumor effects in preclinical studies. We performed a multi-institutional, single-arm, phase II study of RAD001(everolimus), an oral inhibitor of mTOR, in patients who experienced treatment failure on first-line therapy with gemcitabine.Patients and MethodsThirty-three patients with gemcitabine-refractory, metastatic pancreatic cancer were treated continuously with RAD001 at 10 mg daily. Prior treatment with fluorouracil in the perioperative setting was allowed. Patients were observed for toxicity, treatment response, and survival.ResultsTreatment with single-agent RAD001 was well-tolerated; the most common adverse events were mild hyperglycemia and thrombocytopenia. No patients were removed from the study because of drug-related adverse events. No complete or partial treatment responses were noted, and only seven patients (21%) had stable disease at the first restaging scans performed at 2 months. Median progression-free survival and overall survival were 1.8 months and 4.5 months, respectively. One patient (3%) had a biochemical response, defined as ≥ 50% reduction in serum CA19-9.ConclusionAlthough well-tolerated, RAD001 administered as a single-agent had minimal clinical activity in patients with gemcitabine-refractory, metastatic pancreatic cancer. Future studies in metastatic pancreatic cancer should assess the combination of mTOR inhibitors with other agents and/or examine inhibitors of other components of the PI3K/Akt/mTOR pathway.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4827-4827 ◽  
Author(s):  
Asher Alban Chanan-Khan ◽  
Blanche Mavromatis ◽  
Kanti R. Rai ◽  
Philomena Casey ◽  
Steven Novick ◽  
...  

Abstract Bcl-2 is an anti-apoptotic protein closely linked to chemotherapy resistance and inferior survival in patients (pts) with CLL. Genasense(GNS) enhances apoptosis induced by fludarabine (F), dexamethasone, and rituximab (R) in vitro, and has limited single-agent activity in heavily pre-treated CLL pts. Down-regulation of Bcl-2 may further sensitize CLL cells to apoptosis induced by F and R without exposing subjects to the toxicity of alkylating agents. CLL and NHL pts occasionally exhibit a “cytokine release syndrome” (spiking fever, back pain, and occasional hypotension) with GNS treatment. We hypothesized that a “step dosing” approach with GNS, similar to that sometimes used for R, could ameliorate these effects and allow safe and effective combination of this agent with F and R. We are currently evaluating this combination in pts with either previously untreated (UT) or relapsed, previously treated (PT) CLL who require systemic treatment. Eligibility includes: plts ≥ 50,000/mm3; serum Cr ≤ 1.5 mg/dL; adequate organ function; negative Coombs; no history of autoimmune hemolytic anemia. In cycle 1, GNS is given by continuous intravenous infusion at 1.5 mg/kg/d days 1 to 7. R is given on a dose-escalating schema (day 4, 125 mg/m2; day 6, 250 mg/m2). F (25 mg/m2/d) is given on days 6 to 8. In subsequent 28-day cycles (up to 6), the dose of GNS is escalated to 3 mg/kg/d days 1 to7 days, with R 375 mg/m2 on day 5 and F days 5 to7. To date, 20 pts have been enrolled (17 PT and 3 UT). Characteristics included: median age, 62 yrs (range 39 to 82 yrs); Rai stage III (2 pts) and IV (6 pts). Prior to administration of either F or R, single-agent GNS treatment at the initial reduced dose in Cycle 1 resulted in a median decrease in lymphocytes of 15% (among all patients regardless of decline in lymphocyte count) (Baseline: 48.3 cells x 103/ml; day 4: 40.1 cells x 103/ml). For the 13 pts who experienced a decline in lymphocyte count in cycle 1 prior to F and R, the median percentage change was 17%, with 4 pts having a &gt; 25% decrease. Three PT pts discontinued from study treatment prior to completing 6 cycles, 2 due to disease progression, and 1 with Grade 3 thrombocytopenia that was unresolved after 4 weeks. Among the 20 pts treated to date (9 ongoing), the most common grade 3 or higher adverse events have been neutropenia, pyrexia and thrombocytopenia. Serious adverse events have been noted in only 6 of 20 pts (all PT pts) and have included 2 pts with fever (1 neutropenic), 2 R infusion reactions, 1 lymph node abscess and 1 tumor lysis syndrome (with sepsis). Conclusions: 20 pts have been treated with combination GNS, F and R. Single-agent activity with GNS has been observed at a reduced dose of 1.5 mg/kg/d in cycle 1. The “step dosing” approach appears to be a well-tolerated, alternative approach to the administration of GNS. Further details of safety and efficacy will be presented.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4728-4728
Author(s):  
Brady E. Beltrán-Gárate ◽  
Julia Huamani-Zavala ◽  
Alfredo Aronés-Valdivia ◽  
Antonio A. Carrasco-Yalan ◽  
Fernando Hurtado de Mendoza ◽  
...  

Abstract Objectives: Alemtuzumab (Campath®/Mabcampath®, a humanized anti-CD52 monoclonal antibody) has shown to be effective in the treatment of diverse hematological malignancies, including B-cell chronic lymphocytic leukemia and T-cell prolymphocytic leukemia. Mycosis fungoids (MF) is a low grade T-cell cutaneous lymphoma with indolent course and good prognosis while response to chemotherapy is achieved. We started a prospective phase II study in refractory relapse MF cases (advanced disease) treated with i.v. Alemtuzumab (ClinicalTrial.gov Identifier: NCT 00157274) Methods: From July 2005 to April 2006 a total of eight patients were recruited from 2 centers in Lima-Perú with hystopathological diagnosed of advanced refractory relapse MF. Inclusion criteria include: above 18 years old, ECOG status 0–2, no active infections, no more than 3 previous chemotherapy or radiotherapy, HTLV-1 negative, HIV negative, normal renal or hepatic function and written informed consent. Median age 64 years old (range: 36–72). Five were male. Median number of previous therapies was 2 (range: 2–3). Original treatment scheduled was planed as Alemtuzumab 30 mg i.v. tiw per 12 weeks with a gradually escalated doses during the first week (3, 10, 30 mg). Trimethoprim/sulphamethoxazole and acyclovir prophylaxis was given as regular. Median Alemtuzumab total dose was 283 mg (range: 123–706) over a median of 5 weeks of treatment (range: 3–15). The first four patients (pts.) received the programmed dosification and due toxicity the subsequent 2 pts. received Alemtuzumab 30 mg i.v. tiw for 4 weeks and then 30 mg i.v. weekly and the last 2 recruited pts. received Alemtuzumab 10 mg i.v. tiw for 4 weeks them 10 mg i.v. biw and finally 10 mg i.v. weekly. CMV monitoring with pp65 was performed in the first five pts. and qualitative PCR in the last 3 pts. Results: Seven patients were evaluated for response, overall response rate (ORR) was 57% (4/7), with two pts. achieving complete remission (CR), two pts. with partial response (PR) and three pts. progressive disease (PD) during treatment. Response duration and follow-up and CMV status is described in table 1. Median Pruritus Analogue Scale was reduced from 4 to 1. Grade 1 neutropenia in one pt. and grade 1 thrombocytopenia in one pt. One patient developed urosepsis caused by E. Coli. No cardiac toxicity was reported. Kaposi’s sarcoma was discovered in a CR pt. (pt 4, table 1) Conclusions: Alemtuzumab shows promising clinical activity in patients with advanced MF previously treated. Alemtuzumab s.c. as maintenance therapy or in combination with other agents should be explored in advanced MF. Table 1. Outcomes, follow up and CMV status Alemtuzumab TD (mg) Response Follow-up (m.) CMV status TD=total dose, NE=no evaluable, AD=active disease, m=months, R=Reactivation, F=Fever 1 123 NE AD, 14 m. R with F 2 313 PD Died, 8 m. 3 706 PD AD, 8 m. 4 403 CR Relapse at 6 m. R with F 5 253 CR Relapse at 3 m. R with F 6 493 PR PR, 5 m. 7 123 PR Relapse at 3 m. R no F 8 163 PD AD, 3 m. R no F


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 754-754 ◽  
Author(s):  
Alessandra Ferrajoli ◽  
Michael J. Keating ◽  
William G. Wierda ◽  
Susan M. O’Brien ◽  
Swaminathan Padmanabhan ◽  
...  

Genomic abnormalities, according to the Dohner hierarchical classification, are an important prognostic factor in chronic lymphocytic lymphoma (CLL). Specific chromosomal aberrations, such as a deletion 17p (P53 abnormalities) and deletion 11q (ATM defects), are associated with aggressive disease and inferior response to purine analogue-based chemotherapy. Lenalidomide is an immunomodulatory agent that has demonstrated clinical efficacy in patients with relapsed or refractory CLL in 2 separate phase II clinical trials (Chanan-Khan et al. JCO 2006; Ferrajoli et al. Blood 2006 abst). To investigate the clinical activity of lenalidomide in patients with high-risk cytogenetics (17p or 11q abnormalities), we reviewed data from 2 clinical studies. On these studies, lenalidomide was given orally either at 10 mg daily for 28 days followed by 5 mg increments every 28 days to a maximum dose of 25 mg (study A) or given at 25 mg on day 1–21 of each 28 day cycle (study B). The presence of deletion 17p or deletion 11q was demonstrated by interphase fluorescence in situ hybridization (FISH) analysis. Clinical responses were assessed using the NCI-WG 1996 criteria. Among the 80 patients treated, 40 patients with deletion 17p or deletion 11q were identified. Their characteristics are described in Table 1. The overall response rate in patients carrying deletion 17p or 11q was 35% (14/40) and responses are depicted in Table 2. Median response duration was 12 months in both studies. Based on our experience, single agent lenalidomide induces complete and partial responses in patients with unfavorable genomic aberrations, a group characterized by a poor outcome in several studies. The activity of this agent warrants further evaluation in this patient population. Table 1. Characteristics of 40 patients with unfavorable cytogenetics Study A Study B N=24 N=16 Median age, years (range) 63 (49–86) 62 (56–75) Rai stage III/IV 13 (54%) 4 (25%) Median no. of prior therapies (range) 3 (1–15) 3 (1–10) Median beta 2 microglobulin (range) 4.5 (1.9–10.1) 4 (2–10) Table 2. Responses according to NCI-WG criteria in 40 patients with unfavorable cytogenetics. Response Study A Study B 17p- (N=8) 11q- (N=16) 17p-/11q- (n=24) 17p- (N=6) 11q- (n=10) 17p-/11q- (N=16) CR, n 0 2 2 0 1 1 PR, n 1 4 5 3 3 6 OR, n (%) 1 (13) 6 (38) 7 (29) 3 (50) 4 (40) 7 (44)


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4209-4209
Author(s):  
Ann Maclaren ◽  
Amy Trauernicht ◽  
Lizbeth Nguyen ◽  
Karen McLachlan

Abstract Chronic lymphocytic leukemia (CLL) is a B cell malignancy characterized by the accumulation of mature phenotype leukemic B cells in blood, spleen and lymphoid tissues. While many patients respond initially to combination chemotherapy regimens, many become chemoresistant and all will ultimately relapse. Recently the addition of novel monoclonal antibody therapies such as rituximab and alemtuzumab to these treatment regimens has provided additional therapeutic benefit to chemorefractory CLL patients and prompted interest in the evaluation of additional B cell surface antigens as targets. Lumiliximab is a primatized monoclonal antibody directed against CD23, a glycoprotein expressed on the majority of CLL cells, and is currently under investigation in patients with relapsed CLL. It was previously demonstrated that the primary mechanism of action of lumiliximab in both CD23+ lymphoma B cells and CLL patient samples is sensitization to apoptotic cell death and that lumiliximab enhances apoptosis in vivo when combined with either fludarabine or rituximab (Pathan et al., Blood, 2008). In the present study we sought to determine whether lumiliximab could enhance the apoptotic activity of a range of CLL therapies which induce cell death via distinct apoptotic pathways. Our studies demonstrate that the addition of lumiliximab in combination with the alkylating agent chlorambucil resulted in a dose-dependent and significant increase in apoptosis of CD23+ lymphoma cells. Lumiliximab also resulted in statistically significantly enhanced apoptosis when combined with alemtuzumab as compared to either single agent alone in both CD23+/CD52+ lymphoma cells and CLL patient samples. Examination of the apoptotic pathways induced by these agents revealed that lumiliximab in combination resulted in more dramatic alterations in downstream effectors of apoptosis such as caspase 3, PARP, and DNA fragmentation. Further studies are ongoing to confirm these observations in xenograft models and to delineate the mechanistic basis of the enhanced apoptotic signaling. These data suggest that the use of lumiliximab in combination with current or emerging CLL therapies could be an effective strategy to augment tumor cell killing and may result in new and more effective treatment regimens for the eradication of CLL.


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