Stephanie A. Gregory

Inhibition of Syk with fostamatinib disodium has significant clinical activity in non-Hodgkin lymphoma and chronic lymphocytic leukemia

Certain malignant B cells rely on B-cell receptor (BCR)-mediated survival signals. Spleen tyrosine kinase (Syk) initiates and amplifies the BCR signal. In in vivo analyses of B-cell lymphoma cell lines and primary tumors, Syk inhibition induces apoptosis. These data prompted a phase 1/2 clinical trial of fostamatinib disodium, the first clinically available oral Syk inhibitor, in patients with recurrent B-cell non-Hodgkin lymphoma (B-NHL). Dose-limiting toxicity in the phase 1 portion was neutropenia, diarrhea, and thrombocytopenia, and 200 mg twice daily was chosen for phase 2 testing. Sixty-eight patients with recurrent B-NHL were then enrolled in 3 cohorts: (1) diffuse large B-cell lymphoma (DLBCL), (2) follicular lymphoma (FL), and (3) other NHL, including mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), mucosa-associated lymphoid tissue lymphoma, lymphoplasmacytic lymphomas, and small lymphocytic leukemia/chronic lymphocytic leukemia (SLL/CLL). Common toxicities included diarrhea, fatigue, cytopenias, hypertension, and nausea. Objective response rates were 22% (5 of 23) for DLBCL, 10% (2 of 21) for FL, 55% (6 of 11) for SLL/CLL, and 11% (1/9) for MCL. Median progression-free survival was 4.2 months. Disrupting BCR-induced signaling by inhibiting Syk represents a novel and active therapeutic approach for NHL and SLL/CLL. This trial was registered at www.clinicaltrials.gov as #NCT00446095.

Disabling Immune Tolerance by Programmed Death-1 Blockade With Pidilizumab After Autologous Hematopoietic Stem-Cell Transplantation for Diffuse Large B-Cell Lymphoma: Results of an International Phase II Trial

PURPOSE The Programmed Death-1 (PD-1) immune checkpoint pathway may be usurped by tumors, including diffuse large B-cell lymphoma (DLBCL), to evade immune surveillance. The reconstituting immune landscape after autologous hematopoietic stem-cell transplantation (AHSCT) may be particularly favorable for breaking immune tolerance through PD-1 blockade. PATIENTS AND METHODS We conducted an international phase II study of pidilizumab, an anti-PD-1 monoclonal antibody, in patients with DLBCL undergoing AHSCT, with correlative studies of lymphocyte subsets. Patients received three doses of pidilizumab beginning 1 to 3 months after AHSCT. RESULTS Sixty-six eligible patients were treated. Toxicity was mild. At 16 months after the first treatment, progression-free survival (PFS) was 0.72 (90% CI, 0.60 to 0.82), meeting the primary end point. Among the 24 high-risk patients who remained positive on positron emission tomography after salvage chemotherapy, the 16-month PFS was 0.70 (90% CI, 0.51 to 0.82). Among the 35 patients with measurable disease after AHSCT, the overall response rate after pidilizumab treatment was 51%. Treatment was associated with increases in circulating lymphocyte subsets including PD-L1E-bearing lymphocytes, suggesting an on-target in vivo effect of pidilizumab. CONCLUSION This is the first demonstration of clinical activity of PD-1 blockade in DLBCL. Given these results, PD-1 blockade after AHSCT using pidilizumab may represent a promising therapeutic strategy in this disease.

Multicenter Analysis of 80 Solid Organ Transplantation Recipients With Post-Transplantation Lymphoproliferative Disease: Outcomes and Prognostic Factors in the Modern Era

PURPOSE Adult post-transplantation lymphoproliferative disease (PTLD) has a reported 3-year overall survival (OS) of 35% to 40%. The impact of rituximab on the outcome of PTLD is not well defined. METHODS We examined the clinical features and outcomes among a large cohort of solid organ transplantation (SOT) -related patients with PTLD who were recently treated at four Chicago institutions (from January 1998 to January 2008). Results Eighty patients with PTLD were identified who had a median SOT-to-PTLD time of 48 months (range, 1 to 216 months). All patients had reduction of immunosuppression as part of initial therapy, whereas 59 (74%) of 80 patients received concurrent first-line rituximab with or without chemotherapy. During 40-month median follow-up, 3-year progression-free survival (PFS) for all patients was 57%, and the 3-year overall survival (OS) rate was 62%. Patients who received rituximab-based therapy as part of initial treatment had 3-year PFS of 70% and OS 73% compared with 21% (P < .0001) and 33% (P = .0001), respectively, without rituximab. Notably, of all relapses, only 9% (4 of 34 patients) occurred beyond 12 months from PTLD diagnosis. On multivariate regression analysis, three factors were associated with progression and survival: CNS involvement (PFS, 4.70; P = .01; OS, 3.61; P = .04), bone marrow involvement (PFS, 2.95; P = .03; OS, 3.14; P = .03), and hypoalbuminemia (PFS, 2.96; P = .05; OS, 3.64; P = .04). Furthermore, a survival model by multivariate CART analysis that was based on number of adverse factors present (ie, 0, 1, > or = 2) was formed: 3-year PFS rates were 84%, 66%, 7%, respectively, and 3-year OS rates were 93%, 68%, 11%, respectively (P < .0001). CONCLUSION This large, multicenter, retrospective analysis suggests significantly improved PFS and OS associated with early rituximab-based treatment in PTLD. In addition, clinical factors at diagnosis identified patients with markedly divergent outcomes.

Measurement of apoptosis, proliferation and three cytokines in 46 patients with myelodysplastic syndromes

Extensive apoptosis or programmed cell death (PCD) of both hematopoietic (erythroid, myeloid, megakaryocytic) and stromal cells in myelodysplastic syndromes (MDS) cancels the high birth-rate resulting in ineffective hematopoiesis and has been demonstrated as the probable basis for peripheral cytopenias in MDS by our group. It is proposed that factors present in the microenvironment are inducing apoptosis in all the cells whether stromal or parenchymal. To investigate this hypothesis further, bone marrow biopsies from 46 MDS patients and eight normal individuals were examined for the presence of three cytokines, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta) and granulocyte macrophage-colony stimulating factor (GM-CSF) and one cellular component, macrophages, by the use of monoclonal antibodies immunohistochemically. Results showed the presence of TNF-alpha and TGF-beta in 41/46 and 40/46 cases of MDS respectively, while only 15 cases showed the presence of GM-CSF. Further a significant direct relationship was found between the degree of TNF-alpha and the incidence of PCD (p= 0.0015). Patients who showed high PCD also had an elevated TNF-alpha level. Thus, the expression of high amounts of TNF-alpha and TGF-beta and low amounts of the viability factor GM-CSF may be responsible for the high incidence of PCD leading to ineffective hematopoiesis in MDS. Future studies will be directed at attempting to reverse the lesion in MDS by using anti-TNF-alpha drugs such as pentoxifylline.

Long term outcomes to Fludarabine and Rituximab in Waldenström macroglobulinemia.

We report the long-term outcome of a multicenter, prospective study examining fludarabine and rituximab in Waldenström macroglobulinemia (WM). WM patients with less than 2 prior therapies were eligible. Intended therapy consisted of 6 cycles (25 mg/m(2) per day for 5 days) of fludarabine and 8 infusions (375 mg/m(2) per week) of rituximab. A total of 43 patients were enrolled. Responses were: complete response (n = 2), very good partial response (n = 14), partial response (n = 21), and minor response (n = 4), for overall and major response rates of 95.3% and 86.0%, respectively. Median time to progression for all patients was 51.2 months and was longer for untreated patients (P = .017) and those achieving at least a very good partial response (P = .049). Grade 3 or higher toxicities included neutropenia (n = 27), thrombocytopenia (n = 7), and pneumonia (n = 6), including 2 patients who died of non-Pneumocystis carinii pneumonia. With a median follow-up of 40.3 months, we observed 3 cases of transformation to aggressive lymphoma and 3 cases of myelodysplastic syndrome/acute myeloid leukemia. The results of this study demonstrate that fludarabine and rituximab are highly active in WM, although short- and long-term toxicities need to be carefully weighed against other available treatment options. This study is registered at clinicaltrials.gov as NCT00020800.

Phase I Trial of Toll-Like Receptor 9 Agonist PF-3512676 with and Following Rituximab in Patients with Recurrent Indolent and Aggressive Non–Hodgkin's Lymphoma

Purpose: PF-3512676 (formerly CpG 7909) is a novel Toll-like receptor 9–activating oligonucleotide with single-agent antitumor activity that augments preclinical rituximab efficacy. This Phase I trial was designed to investigate the safety, tolerability, and preliminary antitumor activity of PF-3512676 in combination with rituximab. Experimental Design: Patients with relapsed/refractory CD20+ B cell non–Hodgkins lymphoma received i.v. rituximab (375 mg/m2/week for 4 weeks) and PF-3512676 weekly for 4 weeks either i.v. (0.04, 0.16, 0.32, or 0.48 mg/kg) or s.c. (0.01, 0.04, 0.08, or 0.16 mg/kg). An additional extended-treatment cohort received 4 weeks of 0.24 mg/kg s.c. PF-3512676 in combination with rituximab followed by s.c. PF-3512676 alone weekly for 20 weeks. Results: Patients (N = 50) had received a median of three prior therapies (range, 1-11) including rituximab in 80% of patients. Treatment-related adverse events occurred in 11 of 19 (58%) i.v. patients, 15 of 19 (79%) s.c. patients, and all 12 patients in the extended-treatment cohort. Most common adverse events were mild to moderate systemic flu-like symptoms and injection-site reactions (s.c. cohorts only). Grade 3/4 neutropenia occurred in four patients. Objective responses occurred in 12 of 50 (24%) patients overall and in 6 of 12 (50%) patients in the extended-treatment cohort, including 2 patients with rituximab-refractory disease. Conclusion: Brief or extended-duration PF-3512676 can be safely administered in combination with rituximab in patients with relapsed/refractory non–Hodgkins lymphoma.

Multicenter Randomized Phase II Study of Weekly or Twice-Weekly Bortezomib Plus Rituximab in Patients With Relapsed or Refractory Follicular or Marginal-Zone B-Cell Lymphoma

PURPOSE To determine overall response rate (ORR), time to progression (TTP), and duration of response (DOR) with twice-weekly/weekly bortezomib plus rituximab, and evaluate safety/tolerability, in patients with relapsed or refractory CD20(+) follicular lymphoma (FL) or marginal-zone lymphoma. PATIENTS AND METHODS Patients were randomly assigned (minimization method) to bortezomib 1.3 mg/m(2) twice weekly (days 1, 4, 8, and 11; 21-day cycle, five cycles; arm A) or bortezomib 1.6 mg/m(2) weekly (days 1, 8, 15, and 22; 35-day cycle, three cycles; arm B) plus rituximab 375 mg/m(2) weekly for 4 weeks (both arms). Response/progression was determined by International Workshop Response Criteria using oncologist/radiologist-adjudicated data from independent radiology review and investigator assessment. RESULTS Eighty-one patients (arm A, n = 41; arm B, n = 40) were enrolled. Dose-intensity was higher in arm A; mean total bortezomib received was similar between arms (18.5 and 17.1 mg/m(2)). In arm A, ORR was 49% (14% complete response [CR]/CR unconfirmed [CRu]), median TTP was 7.0 months, and median DOR was not reached. In arm B, ORR was 43% (10% CR/CRu), and median TTP/DOR were 10.0/9.3 months. The weekly combination regimen seemed better tolerated. Grade 3 or worse adverse events seemed more common in arm A (54%) versus arm B (35%), including thrombocytopenia (10% v 0%) and peripheral neuropathy (10% v 5%), but diarrhea seemed less frequent (7% v 15%). No grade 4 toxicities were reported in arm B. CONCLUSION Both bortezomib plus rituximab regimens seem feasible in relapsed or refractory indolent lymphomas. The more convenient weekly combination regimen is being compared with single-agent rituximab in an ongoing phase III study in relapsed FL.

Mesenchymal stem cells from the Wharton's jelly of umbilical cord segments provide stromal support for the maintenance of cord blood hematopoietic stem cells during long-term ex vivo culture

BACKGROUND: Hematopoietic stem cells (HSCs) are routinely obtained from marrow, mobilized peripheral blood, and umbilical cord blood. Mesenchymal stem cells (MSCs) are traditionally isolated from marrow. Bone marrow–derived MSCs (BM‐MSCs) have previously demonstrated their ability to act as a feeder layer in support of ex vivo cord blood expansion. However, the use of BM‐MSCs to support the growth, differentiation, and engraftment of cord blood may not be ideal for transplant purposes. Therefore, the potential of MSCs from a novel source, the Whartons jelly of umbilical cords, to act as stromal support for the long‐term culture of cord blood HSC was evaluated.

Re-Treatment With I-131 Tositumomab in Patients With Non-Hodgkin's Lymphoma Who Had Previously Responded to I-131 Tositumomab

PURPOSE To study efficacy and safety of re-treatment with I-131 tositumomab in patients with low-grade, follicular, or transformed low-grade B-cell lymphoma who relapsed following a response to I-131 tositumomab. PATIENTS AND METHODS A prior response > or = 3 months to I-131 tositumomab was required. The single therapeutic dose following a dosimetric dose was adjusted to give the same total body dose (in Gy) as that used for the original dose, or was attenuated if the platelet count was less than 150,000 per mm(3) or if the prior treatment resulted in grade 4 cytopenias lasting longer than 7 days. RESULTS Of 32 patients enrolled, 28 completed the therapeutic dose. A median of four therapies were given before re-treatment. Eighteen (56%) of 32 patients had a complete or partial response (median duration, 15.2 months); eight (25%) had a complete response (median duration, 35 months). Five continue in response from 1.8 to 5.7 years, with a median follow-up of 35 months. The overall median response duration was not significantly different for the two treatments, with no clinical factors predicting response or its duration. Ten of 18 re-responders had longer responses with re-treatment, with five having responses > or = 1.5 years longer. Grade 3/4 neutropenia and thrombocytopenia occurred in 50% and 43% of patients, respectively, similar to initial treatment. Antimouse antibodies developed in 10% of patients, and 12% developed elevated serum thyroid-stimulating hormone. Six patients were diagnosed with second malignancies, including four patients who developed myelodysplastic syndrome (one who had not received the therapeutic dose) and one with acute myelogenous leukemia. CONCLUSION Re-treatment with I-131 tositumomab following a previous response can produce second responses that can be durable.

Effects of cytokines on CD20 antigen expression on tumor cells from patients with chronic lymphocytic leukemia

Anti-CD20 antibody is an established treatment for low-grade non-Hodgkins lymphoma (NHL). Augmenting the expression of CD20 antigen on the tumor cells may increase the cell kill and therefore increase the effectiveness of the antibody. To study this, we incubated peripheral blood lymphocytes from CLL patients with the following cytokines: EPO, SCF, TNFalpha, TGFbeta, GMCSF, TPO, IL-1, IL-2, IL-3, IL-4, GCSF. CD20 expression was studied by flow cytometry at baseline, 24 and 72 h after exposure to these cytokines. Upregulation of CD20 antigen expression was observed with IL-4, TNFalpha and GMCSF.