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Biomedical subjects

T E Witzig

Publications and source records attributed to T E Witzig.

At least 37 records · Page 2Linked to original sources
PubMed2001

Radioimmunotherapy for patients with relapsed B-cell non-Hodgkin lymphoma.

Clinical trials of an yttrium-90 (90Y)-conjugated monoclonal antibody to CD20 in patients with relapsed B cell non-Hodgkin lymphoma (NHL) are reviewed. Ibritumomab is the murine parent anti-CD20 antibody engineered to make the human chimeric antibody rituximab. Tiuxetan is an MX-DTPA linker chelator attached to ibritumomab to form ibritumomab tiuxetan (Zevalin). Ibritumomab tiuxetan can react with indium-111 (111In) or 90Y to form 111In-ibritumomab tiuxetan, which is used for dosimetry, or 90Y-ibritumomab tiuxetan, which is used for therapy of B cell NHL. In this report, the results of five separate clinical trials of ibritumomab tiuxetan are reviewed. Two phase I trials of 90Y-ibritumomab tiuxetan were performed, one using cold ibritumomab prior to 90Y-ibritumomab tiuxetan, and one using rituximab prior to 90Y-ibritumomab tiuxetan. The optimal schedule was found to be rituximab on days I and 8, and 90Y-ibritumomab tiuxetan 0.4 mCi/kg i.v. on day 8; no stem cells or prophylactic growth factors were used. A dose of 0.3 mCi/kg was recommended for patients with a baseline platelet count of 100,000-149,000x10(6)/l. The only significant toxicity was reversible myelosuppression. With this schedule, the overall response rate (ORR) was 67% of all patients and 82% of those with low-grade NHL. The phase I/II trials were followed by a phase III trial that randomized 143 eligible patients to either rituximab or 90Y-ibritumomab tiuxetan radioimmunoconjugate to demonstrate that the combination of the 90Y radioisotope to the murine anti-CD20 antibody provided additional efficacy over the unconjugated ("cold") rituximab alone. A planned interim analysis of the first 90 patients demonstrated an ORR of 80% with 90Y-ibritumomab tiuxetan vs 44% for rituximab (P < 0.05). To provide additional evidence of the benefit of 90Y radioimmunotherapy over rituximab immunotherapy, patients who were nonresponsive or refractory to rituximab were enrolled in an additional trial and treated with 90Y-ibritumomab tiuxetan 0.4 mCi/kg. An ORR of 46% was achieved in these rituximab-refractory patients. These results provide further evidence of the added value of 90Y. Therefore 90Y-ibritumomab tiuxetan radioimmunotherapy is a useful new treatment modality for patients with B cell NHL. Future trials are needed to define the optimal time in the disease course when this modality should be used.

Antibodies, Monoclonal↗
PubMed2001

Phase I trial of sequential administration of raltitrexed (Tomudex) and 5-iodo-2'-deoxyuridine (IdUrd).

Raltitrexed (Tomudex) is a specific inhibitor of thymidylate synthase with clinical activity in colorectal cancer. The combination of raltitrexed and 5-iodo-2'-deoxyuridine (IdUrd, a cytotoxic pyrimidine analog) resulted in increased IdUrd incorporation into DNA and exhibited in vitro synergism against colon and bladder human carcinoma cell lines. We designed a phase I trial to determine the MTD, pharmacokinetics, and biologic effects of escalating doses of the combination of IdUrd given as a 24-hour infusion after a raltitrexed 15-minute infusion every three weeks. Thirty-four patients received 95 courses of raltitrexed and IdUrd at doses ranging from raltitrexed 1 mg/m2 and IdUrd 750 mg/m2 to raltitrexed 2.5 mg/m2 and IdUrd 10,400 mg/m2. The median number of cycles administered was 2 (range 1-10). Dose limiting hematologic toxicity occurred at doses of raltitrexed 2.5 mg/m2 and IdUrd 10,400 mg/m2. In addition, we determined the mean plasma concentrations C(SS) of IdUrd, the iodouracil level at 22 hours and the IdUrd clearance. Raltitrexed did not appear to affect the pharmacokinetics of IdUrd in the dose range tested. The recommended phase II dose is raltitrexed 2 mg/m2 and IdUrd 10,400 mg/m2 repeated every three weeks. Evidence of potential antitumor activity was observed: 1 patient (with colon cancer) had a partial response while 15 others had stable disease.

Adult↗
PubMed2001

A phase II study of sequential combination chemotherapy with cyclophosphamide, prednisone, and 2-chlorodeoxyadenosine in previously untreated patients with chronic lymphocytic leukemia.

In an earlier study of previously untreated patients with chronic lymphocytic leukemia (CLL), we used a concomitant combination of chlorambucil and 2-chlorodeoxyadenosine and reported overall (OR) and complete (CR) remission rates of 80% and 20%, respectively. After a median follow-up of 5 years, more than 80% of the responders have had a relapse. In the current phase II study of 27 previously untreated patients with CLL, we used a sequential combination of six cycles of intravenous cyclophosphamide (1 g/m2) plus oral prednisone (100 mg/m2 per day for 5 days) followed by two to six cycles of 2-chlorodeoxyadenosine (5 mg/m2 per day for 5 days). The OR and CR rates were 96% and 33%, respectively. After a median follow-up of 29 months, 35% of the responders have had a relapse. Progression-free survival was significantly better in CR patients than in those with partial remission. However, minimal residual disease was phenotypically detected in four of the nine CR patients. Despite the fact that the current OR and CR rates are superior to those seen in a historical cohort treated with a concomitant schedule, a longer follow-up period is needed to assess the durability of these remissions, and a controlled trial is necessary to estimate the impact on overall survival and toxicity.

Adult↗
PubMed2001

Thalidomide for previously untreated indolent or smoldering multiple myeloma.

We conducted a clinical trial of thalidomide as initial therapy for asymptomatic smoldering (SMM) or indolent multiple myeloma (IMM). Sixteen patients were studied. Thalidomide was given orally at a dose of 200 mg/day for 2 weeks, and then increased as tolerated by 200 mg/day every 2 weeks to a maximum dose of 800 mg/day. Bone marrow microvessel density (MVD) and angiogenesis grading were estimated using CD34 immunostaining. Six patients had a confirmed response to therapy with at least 50% or greater reduction in serum and urine monoclonal (M) protein. When minor responses (25-49%) decrease in M protein concentration) were included, 11 of 16 patients (69%) responded to therapy. Major grade 3-4 toxicities included two patients with somnolence, and one patient each with syncope and neutropenia. Pre-treatment MVD was not a significant predictor of response to therapy, median MVD 4 and 12 in responders and non-responders respectively, P = 0.09. We conclude that thalidomide has significant activity in the treatment of newly diagnosed SMM/IMM. However, we do not recommend treatment with thalidomide at this stage since some patients with SMM/IMM can be stable for several months or years without any therapy. Additional randomized trials are needed to determine if thalidomide will delay progression to active multiple myeloma.

Administration, Oral↗
PubMed2001

Analysis of clonal B-cell CD38 and immunoglobulin variable region sequence status in relation to clinical outcome for B-chronic lymphocytic leukaemia.

Recent reports suggest that the expression of germline (GL) Ig variable region heavy-chain genes (VH) is a negative prognostic factor for B-cell chronic lymphocytic leukaemia (B-CLL) patients and that CLL B-cell CD38 expression may be a surrogate marker of Ig VH gene status. Currently, however, the usefulness of this surrogate marker is controversial. Therefore, our goal was to study the ability of CD38 to act as a surrogate marker for Ig VH somatic mutation (SM), and to identify differences in overall survival (OS), progression-free survival (PFS) and response in B-CLL patients based on these two markers. We first assessed the relationship between CD38 expression and Ig VH status on 131 B-CLL patients, including 66 patients enrolled in three North Central Cancer Treatment Group Trials. Although the mean percentages of CD38+ clonal B cells were significantly higher for patients classified as GL versus SM, CD38 was not a reliable marker for clonal B-cell SM. Overall, GL patients exhibited significantly shorter OS and PFS times than SM patients. Despite the inability of clonal B-cell CD38 expression to predict Ig VH mutation status, patients with < or =30% CD38+ cells did have shorter PFS and OS times than did CLL patients with < 30% CD38+ cells. Thus, the relationship between CD38 expression and Ig VH mutation status in B-CLL is not straightforward. Nevertheless, analysis in a co-operative group clinical trial setting suggests that both B-cell markers alone or in combination may have clinical usefulness. These data strongly encourage the study of these biological markers as they relate to disease heterogeneity in B-CLL.

ADP-ribosyl Cyclase↗
PubMed2000

Testicular lymphoma is associated with a high incidence of extranodal recurrence.

BACKGROUND: Testicular lymphoma is a rare extranodal presentation of non-Hodgkin lymphoma. The authors report long term follow-up information regarding a group of patients with testicular lymphoma evaluated at the Mayo Clinic and describe the outcome with special attention to patterns of recurrence. METHODS: The medical records of patients with testicular lymphoma seen at the Mayo Clinic between January 1970 and March 1993 were reviewed. Patients were included if they had evidence of testicular involvement at the time of diagnosis of lymphoma. Pathology specimens were reviewed for confirmation of diagnosis. RESULTS: Sixty-two patients with a diagnosis of testicular lymphoma were identified. Their median age was 68 years, and 60 patients underwent orchiectomy as the initial therapeutic and diagnostic procedure. Most of patients (79%) had localized or regional disease at the time of presentation. Other treatment modalities after diagnosis included radiotherapy (37%), combination chemotherapy (37%), and combination chemotherapy and radiotherapy (16%). Although 88% of patients had no residual disease after primary treatment, 80% subsequently experienced disease recurrence. There was no significant difference in the rate of recurrence, including Ann Arbor Stage I disease. Treatment did not appear to affect the recurrence rate. At a median follow-up of 2.7 years, 60% of patients had died of disease. Late recurrences were observed, and there appeared to be no plateau in the disease free survival curve. In half (51%) of the patients with disease recurrence, only extranodal locations were involved. Thirteen patients experienced recurrence in the central nervous system, 11 of whom had parenchymal lesions. In 8 of these 13 patients, the central nervous system was an isolated site of disease recurrence. CONCLUSIONS: Testicular lymphoma is a unique and aggressive extranodal non-Hodgkin lymphoma. Better treatment strategies are needed to prevent recurrences. The risk of extranodal recurrence is high, especially in the central nervous system.

Adult↗
PubMed2000

Phase I/II 90Y-Zevalin (yttrium-90 ibritumomab tiuxetan, IDEC-Y2B8) radioimmunotherapy dosimetry results in relapsed or refractory non-Hodgkin's lymphoma.

Dosimetry studies in patients with non-Hodgkin's lymphoma were performed to estimate the radiation absorbed dose to normal organs and bone marrow from 90Y-Zevalin (yttrium-90 ibritumomab tiuxetan, IDEC-Y2B8) treatment in this phase I/II, multicenter trial. The trial was designed to determine the dose of Rituximab (chimeric anti-CD20, Rituxan, IDEC-C2B8, MabThera), the unlabeled antibody given prior to the radioconjugate to clear peripheral blood B cells and optimize distribution, and to determine the maximum tolerated dose of 90Y-Zevalin [7.4, 11, or 15 MBq/kg (0.2, 0.3, or 0.4 mCi/kg)]. Patients received (111)In-Zevalin (indium-111 ibritumomab tiuxetan, IDEC-In2B8 ) on day 0 followed by a therapeutic dose of 90Y-Zevalin on day 7. Both doses were preceded by an infusion of the chimeric, unlabeled antibody Rituximab. Following administration of (111)In-Zevalin, serial anterior/posterior whole-body scans were acquired. Major-organ radioactivity versus time estimates were calculated using regions of interest. Residence times were computed and entered into the MIRDOSE3 computer software program to calculate estimated radiation absorbed dose to each organ. Initial analyses of estimated radiation absorbed dose were completed at the clinical site. An additional, centralized dosimetry analysis was performed subsequently to provide a consistent analysis of data collected from the seven clinical sites. In all patients with dosimetry data (n=56), normal organ and red marrow radiation absorbed doses were estimated to be well under the protocol-defined upper limit of 20 Gy and 3 Gy, respectively. Median estimated radiation absorbed dose was 3.4 Gy to liver (range 1.2-7.8 Gy), 2.6 Gy to lungs (range 0.72-4.4 Gy), and 0.38 Gy to kidneys (range 0.07-0.61 Gy). Median estimated tumor radiation absorbed dose was 17 Gy (range 5.8-67 Gy). No correlation was noted between hematologic toxicity and the following variables: red marrow radiation absorbed dose, blood T(1/2), blood AUC, plasma T(1/2), and plasma AUC. It is concluded that 90Y-Zevalin administered at nonmyeloablative maximum tolerated doses results in acceptable radiation absorbed doses to normal organs. The only toxicity of note is hematologic and is not correlated to red marrow radiation absorbed dose estimates or T(1/2), reflecting that hematologic toxicity is dependent on bone marrow reserve in this heavily pretreated population.

Antibodies, Monoclonal↗
PubMed2000

Delayed stem cell transplantation for the management of relapsed or refractory multiple myeloma.

The optimal timing of stem cell transplantation for multiple myeloma is controversial. Late stem cell collection is undesirable because of the inability to mobilize stem cells. We report on 64 recipients of stem cells collected within 1 year after diagnosis, none of whom had transplantation in plateau phase of their disease. Patients seen within 12 months after diagnosis received four cycles of standard vincristine, doxorubicin, and dexamethasone (VAD) chemotherapy and then had stem cells mobilized. Patients were then placed on maintenance vincristine, BCNU, melphalan, cyclophosphamide, and prednisone or melphalan and prednisone chemotherapy for 12 cycles. At the sign of first progression, transplantation occurred. Fourteen patients were refractory to VAD chemotherapy, 20 relapsed on maintenance chemotherapy, and 30 relapsed off chemotherapy. The time to platelet engraftment was not affected by the duration of stem cell cryopreservation or extent of chemotherapy exposure after mobilization. The complete response rate was 34%. The actuarial median survival from initial diagnosis, from transplant day 0, and post-transplant progression-free survival was 51, 20 and 11.4 months, respectively. The patient status at transplantation and percentage of plasma cells circulating in the blood at apheresis influenced post-transplant survival; circulating plasma cells, status at transplantation and plasma cell labeling index influenced progression-free survival. Response duration was shorter in patients relapsing on chemotherapy.

Adult↗
PubMed2000

Effect of complete response on outcome following autologous stem cell transplantation for myeloma.

We studied the effect of complete response (CR) among 126 consecutive patients who underwent stem cell transplantation (SCT) for myeloma. The CR rate with SCT was 33%. Median overall survival (OS) from diagnosis of myeloma was 56 months. OS following SCT was 22 months. Progression-free survival (PFS) was 12 months. OS was not different between patients who achieved CR and those who did not, median survival 25 vs 24 months, P = 0.5. Corresponding median times for PFS were 15 and 11 months, P = 0.2. The plasma cell labeling index (PCLI) was high (> or = 1%) in 36% (high risk group) and was associated with poor OS and PFS (P < 0.001). Achieving CR did not influence OS or PFS in either the high or the low risk group. In contrast, OS and PFS were significantly influenced by high PCLI both in patients who achieved CR and those who did not. OS was poor (< 30 months) in high risk patients regardless of CR status and in low risk patients who did not achieve CR, compared to low risk patients achieving CR (57 months), making them candidates for novel post-transplant treatment options. Outcome following SCT is dependent more on biological variables such as the PCLI than on CR status.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Waldenström's macroglobulinaemia: a prospective study comparing daily with intermittent oral chlorambucil.

This prospective study compared continuous and intermittent chlorambucil therapy of untreated Waldenström's macroglobulinaemia. The diagnosis was established by the presence of an IgM monoclonal (M-) protein in the serum, an infiltrate of lymphocytes and plasma cells in the bone marrow, anaemia or other laboratory abnormalities, physical findings or constitutional symptoms. Patients were randomized to receive chlorambucil 0.1 mg/kg/d or chlorambucil 0.3 mg/kg/d orally for 7 d, repeated every 6 weeks. Criteria for response included 50% or more reduction of serum M-protein, increase in haemoglobin level of 2 g/dl without transfusion, >/= 50% decrease of urine M-protein, or a reduction of 2 cm in the size of the liver, spleen or lymph nodes. Forty-six patients were randomized to continuous chlorambucil (n = 24) or to intermittent chlorambucil (n = 22). Nineteen (79%) (95% CI = 58-93) of the 24 patients given continuous therapy had an objective improvement by either reduction of serum M-protein or increase in haemoglobin. Fifteen (68%) (95% CI = 45-86) of the 22 patients given chlorambucil intermittently had an objective response. The size of the liver decreased by >/= 2 cm in 55% of patients, and the size of the spleen decreased >/= 2 cm in 67%. Lymphadenopathy decreased in 71%. Acute leukaemia or refractory anaemia developed in four patients. The median duration of survival was 5.4 years, and there was no difference between the regimens. Chlorambucil is effective for the treatment of Waldenström's macroglobulinaemia. Patients must be treated for at least 6 months before therapy is abandoned because response is slow. Chlorambucil is an effective agent and should be compared with purine analogues or rituxan (Rituximab) in a prospective study.

Aged↗
PubMed2000

A review of angiogenesis and antiangiogenic therapy with thalidomide in multiple myeloma.

Angiogenesis is the formation of new blood vessels and occurs physiologically during embryonal growth, wound healing and during the menstrual cycle. It is essential for the proliferation and metastases of most malignant neoplasms. Recent evidence suggests that angiogenesis is increased in multiple myeloma and has prognostic value in the disease. Angiogenic cytokines such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor are expressed by myeloma cells and appear to play a role in the increased angiogenesis seen in myeloma. In addition, VEGF may serve as a paracrine growth factor for myeloma cells. Based on the increased angiogenesis observed in myeloma, thalidomide has been studied as antiangiogenic therapy. Although its mechanism of action in myeloma is still unclear, thalidomide appears to be active in 25-30% of patients with refractory myeloma. Major toxicities include constipation, sedation, skin rash, fatigue, and peripheral neuropathy. Studies are ongoing to determine its role as initial treatment for myeloma. This paper reviews the available data on angiogenesis in myeloma, and summarizes the role of thalidomide therapy in this disease. The pharmacology and toxicity of thalidomide are also discussed.

Angiogenesis Inhibitors↗
PubMed2000

A prospective study of CD38/45 flow cytometry and immunofluorescence microscopy to detect blood plasma cells in patients with plasma cell proliferative disorders.

Malignant plasma cells can be detected in the blood of patients with multiple myeloma (MM) using flow cytometry (FC), immunofluorescence microscopy (IM), or a variety of molecular techniques. Increased numbers of light chain-restricted blood plasma cells as detected by IM is associated with a diagnosis of overt MM and a decreased overall survival. The IM technique is time consuming; therefore, a prospective study was designed to test whether CD38 CD45 FC could simplify the procedure. Blood samples from 769 patients with plasma cell proliferative disorders were studied prospectively by FC and IM over a one-year period. The FC technique was performed on 1 ml of whole blood after ammonium chloride red blood cell lysis and utilized anti-CD38PE and anti-CD45PerCP. The number of CD38+ 45- events were enumerated and compared to the number of light chain-restricted plasma cells detected by the standard IM technique. In 46% (353/769) of cases > or = 1 CD38+ CD45- events were detected by FC whereas IM was positive for light chain restricted plasma cells in 33%; there was concordance between FC and IM in 73% of cases. In 20% of cases FC was positive and IM was negative; however, in 7% of cases FC was negative yet light chain-restricted plasma cells were detected by IM. FC was positive in 88% (134/153) of cases where the IM technique showed a high number of circulating plasma cells. This study demonstrates that two-color CD38/45 FC identifies most cases with a high IM result and reduces the workload in the clinical laboratory. The prognostic implications of a positive FC screen but a negative IM will require long-term patient follow-up.

ADP-ribosyl Cyclase↗
PubMed2000

A randomized, placebo-controlled study of outpatient premedication for bone marrow biopsy in adults with lymphoma.

The outpatient bone marrow biopsy and aspiration (BMBA) procedure performed with local anesthetic is often poorly tolerated in adults. This prospective, randomized, placebo-controlled, double-blind trial was designed to determine whether oral (p.o.) lorazepam and hydromorphone reduces pain and anxiety during BMBA. Eligible patients had lymphoma, had no prior BMBA, and were > or = 18 years old. Since patients had bilateral BMBA, each served as their own control. Patients were stratified by anxiety level using the Spielberger Trait Anxiety Scale and randomized to: A) placebo for the first BMBA and 2 mg lorazepam and 2 mg hydromorphone p.o. for the contralateral BMBA, or B) placebo for both BMBAS. Changes in pain and anxiety experienced between the first and second BMBA were measured by the Visual Analogue Scale (VAS) and the Spielberger State Anxiety Scale at the time of the BMBA and 24 hours later. Twenty-seven patients were enrolled and 25 were evaluable; there were 17 males and eight females. The median age was 57 years (range, 28-79 years). Overall, BMBA was reported as painful in both arms, with a median VAS pain score after the second BMBA of 3.9 (scale, 0-10) for arm A and 5.8 for arm B (P = 0.21). There was no difference in the change in pain, anxiety, or recalled anxiety between treatment arms (all P values > 0.05). The difference in the change in recalled pain was of borderline significance (P = 0.07) and consistent with benzodiazepine-induced anterograde amnesia.

Administration, Oral↗
PubMed2000

Thalidomide in the treatment of relapsed multiple myeloma.

OBJECTIVE: To describe the efficacy of therapy with thalidomide, a drug that has antiangiogenic properties, in patients with relapsed multiple myeloma. PATIENTS AND METHODS: We studied 16 patients (median age, 64 years) who received thalidomide for relapsed myeloma at the Mayo Clinic in Rochester, Minn, between November 1998 and August 1999. Treatment consisted of thalidomide given orally at a dose of 200 mg/d for 2 weeks, then increased by 200 mg/d every 2 weeks, up to a maximal dose of 800 mg/d. RESULTS: The stage of myeloma at treatment was Durie-Salmon IIIA in 9 patients (56%) and IIIB in 7 (44%). The median time from myeloma diagnosis to initiation of thalidomide therapy was 32 months. In 4 patients (25%) prior stem cell transplantation had failed, and 14 (88%) had received 2 or more prior chemotherapeutic regimens before institution of thalidomide. All patients were evaluable for response. Four (25%) achieved a partial response to therapy, with a greater than 50% reduction in the serum or urine M protein level. Responses lasted 2, 4+, 8, and 10+ months. Major adverse effects included constipation, sedation, rash, and peripheral neuropathy. CONCLUSION: Thalidomide is an active agent in the treatment of patients with advanced myeloma.

Administration, Oral↗
PubMed2000

Induction of apoptosis in malignant B cells by phenylbutyrate or phenylacetate in combination with chemotherapeutic agents.

Phenylacetate (PA) and phenylbutyrate (PB) are aromatic fatty acids that are presently undergoing evaluation as potential antineoplastic agents. In vitro, PA and PB cause differentiation or growth inhibition of malignant cells. Clinical trials of these drugs as single agents indicate that they are not myelosuppressive; therefore, combinations with other chemotherapy agents may be possible. The goals of this study were to determine whether PA and PB (a) are cytotoxic to malignant B cells from patients with non-Hodgkin's lymphoma and B-cell chronic lymphocytic leukemia and (b) exhibit additive or synergistic induction of apoptosis when administered to myeloma cell lines in combination with conventional drugs. In the clinical specimens, cytotoxicity was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and percent apoptosis was measured using 7-aminoactinomycin D and flow cytometry. Viability was decreased by > 50% in 7% (1/15) of non-Hodgkin's lymphoma samples treated with 5 mM PA, 27% treated with 1 mM PB, and 60% treated with 2 mM PB. Likewise, viability was decreased by > 50% in 44% (4/9) of chronic lymphocytic leukemia samples treated with 5 mM PA, 67% treated with 1 mM PB, and 100% treated with 2 mM PB. Studies in the myeloma cell lines demonstrated that PB treatment induced activation of caspases 3, 7, and 9 accompanied by cleavage of their substrates and internucleosomal DNA degradation. Combinations of PA or PB with conventional drugs (cytarabine, topotecan, doxorubicin, etoposide, chlorambucil, melphalan, fludarabine, carboplatin, and cisplatin) were examined for synergism (combination index < 1 in median effect analysis) in inducing apoptosis of both the MY5 and 8226 human myeloma cell lines. At concentrations that killed > 50% of cells, most combinations were additive; however, PB was synergistic with cytarabine, etoposide, and topotecan, with the combination index < 1 at each of the 50, 75, and 95% apoptosis levels. These observations indicate that PA and PB can induce apoptosis in malignant B cells and enhance the cytotoxicity of agents used in the treatment of these malignancies.

Antineoplastic Agents↗
PubMed2000

Prognostic value of bone marrow angiogenesis in multiple myeloma.

We studied the prognostic value of angiogenesis grading and microvessel density estimation in newly diagnosed multiple myeloma. Seventy-five patients with newly diagnosed myeloma, treated on Eastern Cooperative Oncology Protocol E9486 and Intergroup study 0141 (S9321) at the Mayo Clinic, were studied. Bone marrow microvessels were examined using immunohistochemical staining for von Willebrand factor. Determination of microvessel density and angiogenesis grading was done in a blinded manner. There was a strong correlation between microvessel density and the plasma cell labeling index, rho 0.42, P < 0.001. Angiogenesis grade was also significantly associated with the plasma cell labeling index. Fifteen % of patients with low-grade angiogenesis had a high labeling index (>1%). In contrast, 47% of patients with intermediate or high-grade angiogenesis had high labeling indices (P = 0.02). Overall survival was significantly different among those with high-, intermediate-, and low-grade angiogenesis, with median times of 2, 4, and 4.4 years, respectively (P = 0.02). Similarly, patients with microvessel density >50/x400 field had poorer survival compared with those with 50 or fewer microvessels/field, median survival 2.6 versus 5.1 years, respectively (P = 0.004). There was a strong association between angiogenesis grade and microvessel density (P < 0.001). We conclude that bone marrow angiogenesis is a predictor of poor survival in newly diagnosed myeloma. Angiogenesis is correlated with the plasma cell labeling index but not the bone marrow plasma cell percentage. A simple visual grading of angiogenesis is an efficient alternative to microvessel density estimation.

Bone Marrow↗
PubMed2000

The use of ibritumomab tiuxetan radioimmunotherapy for patients with relapsed B-cell non-Hodgkin's lymphoma.

Rituximab (Rituxan; Genentech, Inc, South San Francisco, CA and IDEC Pharmaceutical Corporation, San Diego, CA) is a monoclonal antibody that targets the CD20 antigen present in most B-cell non-Hodgkin's lymphomas. Previous studies have shown overall response rates (ORR) of approximately 50% in relapsed patients. Ibritumomab is the murine parent anti-CD20 antibody that is linked through a MX-DTPA chelator to yttrium 90 (90Y) to form the radioimmunoconjugate 90Y-ibritumomab tiuxetan (Zevalin; IDEC Pharmaceuticals, San Diego, CA). A phase I study of 90Y-ibritumomab tiuxetan determined that 0.4 mCi/kg was the maximum tolerated dose, and responses were reported in 67% of all patients and in 82% of patients with low-grade non-Hodgkin's lymphoma. A separate trial randomized eligible patients to either rituximab or 90Y-ibritumomab tiuxetan. An interim analysis of the first 90 patients showed an ORR of 80% with 90Y-ibritumomab tiuxetan versus 44% with rituximab (P < .05). A subsequent trial for patients with rituximab-refractory disease showed a 46% ORR. These studies show that 90Y-ibritumomab tiuxetan is an active agent in relapsed non-Hodgkin's lymphoma and appears to have a higher ORR compared with unconjugated rituximab.

Antibodies, Monoclonal↗