Faculty Bibliography

We hypothesized that incremental improvements in the cyclophosphamide-doxorubicin-vincristine-prednisone (CHOP) chemotherapy regimen through optimization of drug selection, schedule, and pharmacokinetics would improve outcome in patients with large B-cell lymphomas. A prospective multi-institutional study of administration of etoposide, vincristine, and doxorubicin for 96 hours with bolus doses of cyclophosphamide and oral prednisone (EPOCH therapy) was done in 50 patients with previously untreated large B-cell lymphomas. The doses of etoposide, doxorubicin, and cyclophosphamide were adjusted 20% each cycle to achieve a nadir absolute neutrophil count below 0.5 x 10(9)/L. The median age of the patients was 46 years (range, 20-88 years); 24% were older than 60 years; and 44% were at high-intermediate or high risk according to International Prognostic Index (IPI) criteria. There was a complete response in 92% of patients, and at the median follow-up time of 62 months, the progression-free survival (PFS) and overall survival (OS) rates were 70% and 73%, respectively. Neither IPI risk factors nor the index itself was associated with response, PFS, or OS. Doses were escalated in 58% of cycles, and toxicity levels were tolerable. Significant inverse correlations were observed between dose intensity and age for all adjusted agents, and drug clearance of doxorubicin and free etoposide was also inversely correlated with age (r = -0.54 and P(2) =.08 and r = -0.45 and P(2) =.034, respectively). Free-etoposide clearance increased significantly during successive cycles (P(2) =.015). Lymphomas with proliferation of at least 80% had somewhat lower progression and those expressing bcl-2 had significantly higher progression (P(2) =.04). Expression of bcl-2 may discriminate the recently described activated B-like from germinal-center B-like large-cell lymphomas and provide important pathobiologic and prognostic information. Dose-adjusted EPOCH may produce more cell kill than CHOP-based regimens. Dynamic dose adjustment may overcome inadequate drug concentrations, particularly in younger patients, and compensate for increased drug clearance over time.

PURPOSE: To evaluate the efficacy of rituximab and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) induction therapy in patients with newly diagnosed mantle-cell lymphoma (MCL). PATIENTS AND METHODS: From March 1997 to May 1999, 40 previously untreated patients with stage II through IV MCL were treated with six cycles of rituximab and CHOP chemotherapy in a phase II trial. Pretreatment and interval peripheral-blood (PB) and bone marrow (BM) specimens were also analyzed by polymerase chain reaction (PCR) for tumor-specific BCL-1/immunoglobulin H (IgH) translocations and clonal IgH rearrangements. Study end points included clinical and molecular response rates and long-term progression-free survival (PFS). RESULTS: Forty-eight percent of patients achieved a complete response (CR)/CR unconfirmed (CRu), and 48% of patients obtained a partial response (PR). However, 28 of the 40 patients have already relapsed or developed progressive disease with a median PFS of 16.6 months. Twenty-five patients had PCR-detectable BCL-1/IgH or clonal IgH products in PB or BM at diagnosis. Nine of the 25 informative patients had no evidence of PCR-detectable disease in PB or BM after rituximab and CHOP therapy. However, patients who achieved molecular remissions in PB or BM had PFS similar to patients without molecular remissions (16.5 v 18.8 months, P =.51). CONCLUSION: Favorable clinical and molecular response rates associated with rituximab and CHOP chemotherapy do not translate into prolonged PFS in MCL. Nevertheless, rituximab and combination chemotherapy may transiently clear PB or BM of detectable tumor cells, prompting additional consideration of antibody-based in vivo purging in subsequent clinical trials.

This study was designed to evaluate the efficacy and toxicity of the immunotoxin N901-blocked ricin (bR) in patients with small-cell lung cancer (SCLC) who achieved a complete or near-complete response following chemotherapy and/or radiation. Treatment consisted of a 7-day continuous infusion of N901-bR at a dose of 30 mg/kg/day followed by patient evaluation with repeat scans. Serum immunotoxin levels, human antimurine antibodies, and antiricin antibodies were determined during the course of the infusion. Nine patients enrolled in the study before it closed following a treatment-related death. Seven patients had extensive-stage disease and entered the study with a more than 90% reduction of their original tumor. Two patients with limited-stage SCLC had no evidence of disease at study entry. Maximum plasma levels of N901-bR ranged from 72-371 ng/mL. Laboratory toxicity consisted of transient transaminitis in 8 patients and creatine kinase elevation in 3 patients, 1 of whom developed premature ventricular contractions. One patient experienced progressive capillary leak syndrome following immunotoxin infusion, which proved fatal. All patients developed antibodies to the infused murine antibody as well as to the toxin. Six patients died of progressive SCLC and 1 patient died of presumed radiation pneumonitis. One patient with limited-stage disease is still alive more than 6 years after therapy. N901-bR therapy was associated with a fatal incident of capillary leak syndrome and a nearly universal development of human antimouse and antiricin antibodies, which limited its further clinical development.

Accumulating evidence suggests that the ability to activate apoptotic pathways may be an important determinant of chemotherapy sensitivity and presents a potentially important new therapeutic strategy. Monoclonal antibodies against the CD20 antigen directly induce apoptosis and may serve to modulate the threshold for chemotherapy-induced apoptosis. Rituximab (Rituxan; Genentech, Inc, South San Francisco, CA, and IDEC Pharmaceuticals, San Diego, CA), a monoclonal antibody against CD20, was combined with dose-adjusted EPOCH (infusional etoposide/vincristine/doxorubicin/bolus cyclophosphamide/prednisone) chemotherapy and tested in 38 untreated or relapsed poor-prognosis aggressive lymphomas. Twenty-three patients were untreated. Of these patients, all had large B-cell histologies, a median age of 52 years, Eastern Cooperative Oncology Group performance status > or = 2 in 30%, and high-intermediate or high International Prognostic Index scores in 61%. Fifteen patients had relapsed or refractory lymphomas. These patients had received a median of two (range, one to four) prior regimens, 67% had aggressive histologies, and 60% had high-intermediate or high International Prognostic Index scores. Complete remissions were achieved in 85% and 64% of untreated and previously treated patients, respectively; additionally 42% of patients with disease refractory before therapy achieved complete remission. At a median follow-up of 12 months, progression-free and overall survival in the previously untreated group was 85% and 79%, respectively, and no patient in complete remission has relapsed. These results suggest that rituximab may modulate the sensitivity of B-cell lymphomas to chemotherapy.

BACKGROUND: Patients with metastatic pancreatic carcinoma have a poor survival. Chemotherapy with gemcitabine is the standard first-line treatment. In a Phase II trial at one academic cancer center, the clinical safety and activity of combining gemcitabine and docetaxel were assessed. METHODS: Patients with previously untreated, advanced pancreatic carcinoma were eligible. Bidimensionally measurable disease or evaluable disease with an elevated tumor marker, good performance status, and adequate organ function were required. Patients received docetaxel 60 mg/m(2) on Day 1 and gemcitabine 600 mg/m(2) on Days 1, 8, and 15 every 28 days. Ciprofloxacin was administered on Days 8-18. Dose attenuations were made as indicated for toxicity. Patients were restaged radiographically after every two cycles. RESULTS: Thirty-four patients were enrolled, and 33 patients were evaluable for response. There were 23 men and 10 women among the evaluable patients. The median age was 63 years, and all patients had an Eastern Cooperative Oncology Group performance status of 0 or 1. Three patients had received prior chemoradiation for postresection adjuvant therapy. One hundred forty-six cycles of chemotherapy were administered, and 5 cycles (3%) in 4 patients (12%) were complicated by febrile neutropenia. Twenty percent and 11% of patients on Day 8 and Day 15 doses of gemcitabine, respectively, were omitted for toxicity. The objective response rate was 18%, and the median survival was 8.9 months (95% confidence interval, 5.2-11.2 months). The 1-year survival rate was 29%. CONCLUSIONS: The combination of gemcitabine and docetaxel in patients with advanced pancreatic carcinoma is well tolerated and is associated with moderate activity despite aggressive dose reduction. Whether combination regimens are more effective than single agents in the treatment of patients with pancreatic carcinoma awaits evaluation in randomized studies.

Clonotypic B cells circulating in patients with multiple myeloma (MM) express CD20, and it has been suggested that these cells may be clonogenic. Furthermore, 20% of patients with MM express CD20 on their bone marrow plasma cells (BMPCs). Therefore, the authors began a phase II clinical study to determine the activity of the anti-CD20 monoclonal antibody rituximab in MM patients. Nineteen previously treated MM patients received 375 mg/m2 rituximab per week for 4 weeks. Three months after initiation of treatment, patients were assessed for response and received a second course of therapy if their disease was stable (SD) or they achieved a partial response (PR). Six of 19 (32%) patients had either a PR (n = 1) or SD (n = 5), with a median time to treatment failure of 5.5 months (mean, 10.3 months; range, 3-27+ months). All six patients who had a PR or SD had CD20+ BMPC. Overall, rituximab therapy was well tolerated. Because most patients with MM poorly express CD20 on their BMPCs, the authors evaluated agents for their ability to induce CD20 expression and thereby facilitate rituximab binding on MM cells. These studies show that interferon-gamma (IFN-y) induced CD20 expression on MM BMPCs, MM B cells, and healthy donor BMPCs. In contrast, CD20 expression on chronic lymphocytic leukemia, follicular non-Hodgkin's lymphoma, healthy donor B cells, and progenitor cells was unaffected by IFN-y. Rituximab binding to the BMPCs of MM patients was also increased after culture with pharmacologically attainable levels of IFN-gamma (1-100 U/mL). In conclusion, these studies suggest that MM patients with CD20+ BMPCs may benefit from rituximab therapy. Furthermore, IFN-gamma induces CD20 expression on MM BMPCs and B cells and facilitates rituximab binding to MM BMPCs, providing the rationale for clinical trials to examine its use with CD20-directed serotherapies in MM.

PURPOSE: To determine the safety and efficacy of the combination of the chimeric anti-CD20 antibody Rituxan (rituximab, IDEC-C2B8; Genentech Inc, South San Francisco, CA) and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy in patients with aggressive non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: Thirty-three patients with previously untreated advanced aggressive B-cell NHL received six infusions of Rituxan (375 mg/m2 per dose) on day 1 of each cycle in combination with six doses of CHOP chemotherapy given on day 3 of each cycle. RESULTS: The ORR by investigator assessment confirmed by the sponsor was 94% (31 of 33 patients). Twenty patients experienced a complete response (CR) (61%), 11 patients had a partial response (PR) (33%), and two patients were classified as having progressive disease. In the 18 patients with an International Prognostic Index (IPI) score > or = 2, the combination of Rituxan plus CHOP achieved an ORR of 89% and CR of 56%. The median duration of response and time to progression had not been reached after a median observation time of 26 months. Twenty-nine of 31 responding patients remained in remission during this follow-up period, including 15 of 16 patients with an IPI score > or = 2. The most frequent adverse events attributed to Rituxan were fever and chills, primarily during the first infusion. Rituxan did not seem to compromise the ability of patients to tolerate CHOP; all patients completed the entire six courses of the combination. The bcl-2 translocation of blood or bone marrow was positive at baseline in 13 patients; 11 patients had follow-up specimens obtained (eight CR, three PR), and all had a negative bcl-2 status after therapy. Only one patient has reconverted to bcl-2 positivity, and all patients remain in clinical remission. CONCLUSION: This is the first report to demonstrate the safety and efficacy of the Rituxan chimeric anti-CD20 antibody in combination with standard-dose CHOP in the treatment of aggressive B-cell lymphoma. The clinical responses are at least comparable to those achieved with CHOP alone with no significant added toxicity. The presence or absence of the bcl-2 translocation did not affect the ability of patients to achieve a CR with this regimen. The ability to achieve sustained remissions in patients with an IPI score > or = 2 warrants further investigation with a randomized study.

BACKGROUND: Single agents have only modest activity as treatment for metastatic pancreatic cancer with response rates of less than 10% and median survivals of less than 6 months. Evaluations of single-agent gemcitabine and rubitecan as second-line treatment for relapsed pancreatic cancer have reported good patient tolerability and median survivals of 3.85 months and 4.7 months, respectively. Regimens incorporating two drugs have demonstrated encouraging activity and clinical impact compared with single-agent therapy. G-FLIP is a regimen designed to incorporate four active single agents into a tolerable and active combination. This analysis is a retrospective evaluation of the efficacy and safety of the G-FLIP regimen as second-line chemotherapy in a series of consecutively treated patients with metastatic pancreatic cancer. METHODS: G-FLIP was administered over 48 hours and repeated every 2 weeks. Day 1 treatment consisted of sequentially administered gemcitabine 500 mg/m(2), irinotecan 80 mg/m(2), leucovorin 300 mg, 5-fluorouracil (5-FU) 400 mg/m(2) bolus followed by infusional 5-FU 600 mg/m(2) over 8 hours. Day 2 treatment consisted of leucovorin 300 mg and 5-FU 400 mg/m(2) bolus, followed by cisplatin 50 to 75 mg/m(2), and then infusional 5-FU 600 mg/m(2) over 8 hours. RESULTS: Thirty-four patients with histologically confirmed metastatic pancreatic cancer were consecutively treated. The median patient age was 64.5 years (range 41-82 years) and all patients had objective disease progression on prior therapy: 32 patients had disease progression with gemcitabine and 31 had disease progression with a gemcitabine/5-fluorouracil/cisplatin combination. Grade 3-4 hematological toxicities included anemia (23%), thrombocytopenia (53%), and neutropenia (38%). There were no grade 3-4 neutropenic fevers, treatment-related mortalities, or withdrawals. Nonhematological grade 3-4 toxicities were rare: nausea/vomiting (3%), neurotoxicity (3%), nephrotoxicity (6%), and diarrhea (3%). Based on RECIST criteria a partial response (PR) was attained in eight patients (24%) and seven patients had stable disease (SD). Seven and six patients who attained a PR or SD, respectively, had disease progression with prior gemcitabine-based therapy. The median time to disease progression for all 34 patients was 3.9 months and 5.9 months for the eight patients who attained a PR. Median overall survival for all 34 patients was 10.3 months. CONCLUSION: Adding a single new drug such as irinotecan to the same first-line chemotherapy combination upon disease progression may be an important alternative to switching to different drug classes for treatment of relapsed/resistant cancer. The promising clinical outcomes and moderate toxicity associated with G-FLIP in this heavily pretreated group warrant development of this novel regimen including tests as first-line therapy in patients with diseases likely to be responsive to the drugs contained in this combination.

This article reviews highlights in the field of hematologic malignancies presented at the 2001 annual meeting of the American Society of Clinical Oncology. Targeted therapies continue to proceed from the laboratory to the clinic. Monoclonal antibody-based therapies predominate, and further data on radioimmunoconjugates (RICs) (tositumomab and Iodine 131 tositumomab [Bexxar] and ibritumomab tiuxetan [Zevalin]) are presented. Both agents have high response rates in relapsed B-cell non-Hodgkin's lymphoma (NHL). Results from the first trial directly comparing an RIC (Zevalin) to an unconjugated antibody (rituximab) are presented. A novel application of RIC therapy as part of high-dose therapy for mantle cell NHL is described. A new fusion toxin, BL22, targets the CD22 antigen and shows marked activity in the treatment of hairy cell leukemia. Similarly, the Hu1D10 monoclonal antibody has activity in B-cell NHL and might have a relatively unique mechanism of action. Finally, advances in the treatment of mucositis are described. These abstracts all describe therapies derived from our enhanced understanding of tumor immunology and molecular biology.

The development of rituximab, an anti-CD20 monoclonal antibody, represents a revolutionary advance in the therapy of hematological malignancies. Rituximab was approved in 1997 by the Food and Drug Administration for the treatment of relapsed or refractory, CD20(+), B-cell, low-grade or follicular non-Hodgkin's lymphoma (NHL). Recent studies have documented activity of rituximab in other CD20-expressing hematological malignancies including mantle cell lymphoma, small lymphocytic lymphoma, aggressive NHL, chronic lymphocytic leukemia, and Waldenstrom's macroglobulinemia. When used in combination with cytotoxic chemotherapy, rituximab achieves response rates of 90%-95% in low-grade follicular and aggressive NHL patients. Currently, rituximab is undergoing intensive investigation in several large phase II and III trials, both as a single agent and in combination with chemotherapy. Clinical research will help define the ultimate role of this agent and its potential impact on survival of patients with B-cell neoplasms. This article describes current clinical trials with rituximab and discusses their significance.