Phase II study of bryostatin 1 in patients with relapsed multiple myeloma.

Bryostatin 1, a macrocyclic lactone isolated from the marine bryozoan Bugula neritina, is a protein kinase C (PKC) modulator which has shown both preclinical and clinical activity in lymphoid malignancies. We conducted a phase II trial of bryostatin 1 administered at a dose of 120 microg/m2 by 72-h continuous infusion every 2 weeks in patients with relapsed multiple myeloma. Treatment was well tolerated with myalgias constituting the primaray toxicity. There were no responses in nine evaluable patients. The preclinical anti-lymphoid activity is strong enough to support further exploration of bryostatin 1 in different schedules and in combination therapy for multiple myeloma.

Non-Hodgkin's lymphoma: an analysis of the Metropolitan Detroit SEER database.

We evaluated incidence and survival trends of non-Hodgkin's lymphoma (NHL) in a large population-based cancer registry. Data regarding demographics, histology, incidence, and survival were obtained on all patients with NHL registered in the Metropolitan Detroit Cancer Surveillance System, a participant in the Surveillance Epidemiology and End Results (SEER) Program of the National Cancer Institute. Incidence and survival trends from 1973 through 1995 were evaluated and stratified based on age at diagnosis, sex, race, and tumor grade. There were 11,978 patients diagnosed with NHL and recorded in the Metropolitan Detroit SEER registry from 1973 to 1995. The age-adjusted incidence rate increased from 8.6 to 15.8 per 100,000, leading to an overall increase in incidence of 83% and an average annual increase of 3.2% per year. Incidence increased significantly (p < 0.05) over time in all age groups except the youngest (ages 0-19) and in all demographic groups studied. Incidence was highest in white men and lowest in black women. The incidence of both low-grade and intermediate/high-grade NHL increased significantly for each age group (p < 0.05) except the youngest (ages 0-19). In the oldest patients (70+ years), the incidence of intermediate/high-grade NHL was almost double that of low-grade NHL. Five-year relative survival increased from 64% (1973-1983) to 68% (1984-1991) for patients with low-grade NHL and from 40% to 44% for those with intermediate/high-grade NHL. The increase in relative survival was only seen in whites, however, with 5-year relative survival in blacks decreased from 53% (1973-1983) to 45% (1984-1991). In metropolitan Detroit, the current NHL epidemic affects all age groups except the very young (ages 0-19), both sexes, and both whites and blacks and is due to increases in the incidence of both low-grade and intermediate/high-grade NHL. Five-year survival rates have increased for whites but not for blacks.

Phase II trial of bryostatin 1 in patients with relapsed low-grade non-Hodgkin's lymphoma and chronic lymphocytic leukemia.

Bryostatin 1 is a natural product isolated from the marine bryozoan Bugula neritina in 1982 and is currently undergoing evaluation in a number of malignancies. Twenty-five patients with relapsed, low-grade non-Hodgkin's lymphoma or chronic lyphocytic leukemia (CLL) received bryostatin 1 by 72-h continuous infusion every 2 weeks at a dose of 120 microg/m2 per course. Patients who progressed while receiving bryostatin 1 alone could participate in a feasibility study by receiving vincristine administered by bolus i.v. injection immediately after the completion of the bryostatin 1 infusion. The dose of vincristine was escalated in groups of three patients as follows: level 1, 0.5 mg/m2; level 2, 1.0 mg/m2; and level 3, 1.4 mg/m2 with vincristine doses capped at 2.0 mg for all patients. Bryostatin 1 alone resulted in one complete remission and two partial remissions. Nine patients received sequential treatment with bryostatin 1 and vincristine. The addition of vincristine at a dose of 2 mg was feasible and caused the expected dose-related sensory neuropathy. Phenotypic analysis by flow cytometric analysis on pre- and post-bryostatin 1-treated peripheral blood lymphocytes revealed up-regulation in the coexpression of CD11c/ CD22 on CD20+ B cells in two of four CLL patients studied, which is consistent with in vitro findings of differentiation of CLL cells to a hairy cell phenotype.

Advances in the biology and treatment of multiple myeloma.

Advances in the understanding of the cellular and molecular derangements involved in the initiation and progression of multiple myeloma are beginning to be translated into novel therapeutic approaches. The myeloma stem cell has been under intense scrutiny regarding its normal B-cell counterpart. Oncogenes, tumor-suppressor genes, and cell-survival genes have all been found to be dysregulated in some myeloma patients. Growth factors, especially interleukin-6, appear to be critical for disease progression, and interruption of autocrine and paracrine loops has been achieved with resultant inhibition of myeloma cell growth. Mechanisms of drug resistance and the implications of the multidrug resistance phenotype are just beginning to be understood. High-dose therapeutic regimens with autologous peripheral blood stem cell or allogeneic bone marrow rescue are rigorously being studied with an emphasis on exploiting the graft-versus-myeloma effect. Pamidronate, a second-generation bisphosponate, has been shown to be effective at decreasing adverse skeletal events in patients with advanced myeloma. The topoisomerase 1 inhibitor, topotecan, has shown activity in an initial study.

Trisomy 6 as a primary karyotypic aberration in hematologic disorders.

We identified seven patients with hematologic disorders and trisomy 6 as the sole karyotypic aberration in bone marrow aspirates or unstimulated peripheral blood. Five patients were male and two were female; all were adults with ages ranging from 22 to 74 years. Three of the seven patients presented with manifestations of peripheral cytopenia. Their bone marrows were hypocellular with slight or no dysplastic changes and without an increase in blasts. One of these patients subsequently developed acute myeloid leukemia (AML-M1). The four remaining patients were initially diagnosed with AML--three consistent with French-American-British classification of M1 and M4 in the fourth patient. These results suggest that trisomy 6 is a nonrandom primary numerical anomaly of myeloid disorders. The association of cytopenia and hypoplastic bone marrow with trisomy 6 may constitute a new, distinctive variant among myelodysplastic syndromes.

Successful treatment of human chronic lymphocytic leukemia xenografts with combination biological agents auristatin PE and bryostatin 1.

We tested the activity of dolastatin 10 (a natural product derived from the shell-less marine mollusk, Dolabella auricularia, a sea hare) and its structural modification, auristatin PE, alone and in combination with bryostatin 1 (a protein kinase C activator derived from the marine bryozoan Bugula neritina) on a human B-cell chronic lymphocytic leukemia cell line (WSU-CLL) and in a severe combined immune deficient (SCID) mouse xenograft model bearing this cell line. WSU-CLL cells were cultured in RPMI 1640 at a concentration of 2 x 10(5)/ml using a 24-well plate. Agents were added to triplicate wells, and cell count, viability, mitosis, and apoptosis were assessed after 24 h of incubation at 37 degrees C. Results showed that dolastatin 10 had no apparent inhibition of cell growth at concentrations less than 500 pg/ml. Auristatin PE, on the other hand, showed significant growth inhibition at concentrations as low as 50 pg/ml. Auristatin PE-treated cultures, at this concentration, exhibited 27 and 4.5% mitosis and apoptosis, respectively. Dolastatin 10, at the same concentration, did not exert any effect and was comparable with that of control cultures. In the WSU-CLL-SCID mouse xenograft model, the efficacy of these agents alone and in combination with bryostatin 1 was evaluated. Tumor growth inhibition (T/C), tumor growth delay (T-C), and log10 kill for dolastatin 10, auristatin PE, and bryostatin 1 were 14%, 25 days, and 1.98; 2%, 25 days, and 1.98; 19%, 13 days, and 1.03, respectively. Auristatin-PE produced cure in three of five mice, whereas dolastatin 10 showed activity but no cures. When given in combination, auristatin PE + bryostatin 1-treated animals were all free of tumors (five of five) for 150 days and were considered cured. Dolastatin 10 + bryostatin 1-treated animals produced cure in only two of five mice. We conclude that: (a) auristatin-PE is more effective in this model than dolastatin 10; (b) auristatin PE can be administered at a concentration 10 times greater than dolastatin 10; (c) there is a synergetic effect between these agents and bryostatin 1, which is more apparent in the bryostatin 1 + auristatin PE combination. The use of these agents should be explored clinically in the treatment of CLL.

Phase I study of bryostatin 1 in patients with relapsed non-Hodgkin's lymphoma and chronic lymphocytic leukemia.

PURPOSE: To define, in a phase I study in relapsed non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL), the maximum-tolerated dose (MTD), major toxicities, and possible antitumor activity of bryostatin 1, a macrocyclic lactone. PATIENTS AND METHODS: Bryostatin 1 was delivered by 72-hour continuous infusion every 2 weeks to patients with relapsed NHL or CLL, at doses that ranged from 12 microg/m2 to 180 microg/m2 per course. Correlative investigations included evaluations of total protein kinase C (PKC) in peripheral blood and lymphoid differentiation in patient tumor tissue. RESULTS: Twenty-nine patients were treated, including three patients with CLL and 26 with NHL. Generalized myalgia was the dose-limiting toxicity (DLT) and occurred in two of three patients treated with bryostatin 1 at 180 microg/m2 per course. Myalgias were dose-related and cumulative, and often started in the thighs and calves, improved with activity, were somewhat responsive to analgesics, and often took weeks to resolve once taken off study. Six patients were treated at the MTD of 120 microg/m2 per course. Myalgia, headache, and fatigue were common. Hematologic toxicity was uncommon. Total cumulative doses of bryostatin 1 up to 1,134 microg/m2 have been administered without untoward toxicity. Eleven patients achieved stable disease for 2 to 19 months. An in vitro assay for total PKC evaluation in patient peripheral-blood samples demonstrated activation within the first 2 hours with subsequent downregulation by 24 hours, which was maintained throughout the duration of the 72-hour infusion. CONCLUSION: This phase I study defined the MTD and recommended phase II dose of bryostatin 1, when administered over 72 hours every 2 weeks, to be 120 microg/m2 (40 microg/m2/d for 3 days). Generalized myalgia was the DLT. Future studies will define the precise activity of bryostatin 1 in subsets of patients with lymphoproliferative malignancies and its efficacy in combination with other agents.

Tumor lysis syndrome in small cell carcinoma and other solid tumors.

OBJECTIVE: To review the risk factors and clinical findings associated with tumor lysis syndrome (TLS) in patients with small cell carcinomas and other solid tumors. METHODS: Reports of TLS in the English-language literature were identified by searching MEDLINE and the bibliographies of relevant case reports, journal articles, and book chapters. All reports identified through these searches, including abstracts from national meetings, were reviewed and included in this analysis. Data regarding clinical and biochemical parameters relevant to the occurrence of TLS were extracted from each report. RESULTS: Of the 25 reported solid tumor patients who developed TLS, 7 had small cell carcinoma, 5 breast cancer, and 4 neuroblastoma. TLS was associated with a variety of treatment regimens, including chemotherapy, immunotherapy, hormonal therapy, radiation therapy, and surgery. Common risk factors for TLS in this population included pretreatment renal insufficiency, elevated serum lactate dehydrogenase (LDH), and hyperuricemia. Among the typical biochemical findings of TLS, acute renal insufficiency and hyperuricemia were identified in nearly all patients and hyperkalemia, hyperphosphatemia, hypocalcemia, and increased serum LDH were reported in over 75% of patients. In addition, seven patients, including the current case, presented with profound metabolic acidosis. Nine of 25 patients died during the acute episode of TLS. CONCLUSIONS: Although TLS occurs infrequently in patients with solid tumors, the risk factors and biochemical abnormalities associated with this potentially fatal complication of therapy must be recognized to allow for adequate monitoring and early initiation of appropriate therapeutic measures.

Bryostatin 1 (bryo1)-induced monocytic differentiation in THP-1 human leukemia cells is associated with enhanced c-fyn tyrosine kinase and M-CSF receptors.

Bryostatin 1 (bryo1), a naturally occurring macrocyclic lactone derived from the marine bryozoan Bugula neritina is a potent protein kinase C (PKC) activator. In this report, we investigated the role of c-fyn protein, a src-related protein tyrosine kinase (PTK), during bryo1-induced monocytic differentiation in a human leukemia cell line, THP-1. Bryo1 treatment for 24 h inhibited the proliferation of THP-1 cells and caused a major fraction of them to become adherent cells with distinct monocyte/macrophage features and enhanced expression of M-CSF receptors (M-CSFR), a hallmark of mature macrophages. The THP-1 cells in control cultures expressed low but detectable levels of c-fyn proteins. Treatment of THP-1 cells with bryo1 resulted in an enhanced expression of c-fyn proteins, but not c-lyn proteins, another member of the src-family of kinases. The bryo1 treatment also enhanced the levels of both c-fyn tyrosine kinase and autophosphorylation activities in THP-1 cells. Using a combined immunoprecipitation and immunoblot analysis, bryo1 was shown to promote an enhanced association between c-fyn kinase and M-CSFR. The inducing activity of bryo1 was associated with PKC activation; treatment of THP-1 cells with bryo1 led to a rapid and transient elevation of total PKC activity in THP-1 cells. These results show that enhanced expression and activation of fyn kinases are critical events associated with monocytic differentiation induced by bryo1 in THP-1 cells. Our findings may be of clinical relevance, as bryo1 has been used in clinical trials of cancer patients.

A blood stem cell transplant in a person with concomitant Hodgkin disease and testicular carcinoma.

We report a patient with concomitant Hodgkin disease and testicular carcinoma who received MOPP chemotherapy and radiation therapy followed by etoposide and cisplatin. The testicular cancer recurred and he received ifosfamide, vinblastine and cisplatin followed by a high-dose carboplatin and etoposide blood stem cell transplant. He has been in complete remission for 6 months.

Biologic and clinical advances in multiple myeloma.

Recent advances in our understanding of the cellular and molecular derangements involved in multiple myeloma are beginning to be translated into novel therapeutic approaches. Growth factors, specifically interleukin-6, appear to be critical for disease progression, and interruption of autocrine and paracrine loops has been achieved, with resultant inhibition of myeloma cell growth. Oncogenes, tumor-suppressor genes, and cell-survival genes have all been found to be dysregulated in some myeloma patients. The implications of acquisition of the multidrug resistance phenotype are just beginning to be understood. High-dose therapeutic regimens with bone marrow or peripheral stem-cell rescue are being studied in an attempt to produce a cure. Autologous marrow and peripheral blood stem-cell transplantation are better suited to the older myeloma patient population than is allogeneic marrow transplantation, and have also yielded promising results.

A comparative structural characterization of the human NSCL-1 and NSCL-2 genes. Two basic helix-loop-helix genes expressed in the developing nervous system.

Human cDNA clones for NSCL-1 and NSCL-2, two basic domain helix-loop-helix (bHLH) genes expressed predominantly in the developing nervous system, were obtained from a fetal brain cDNA library. The full-length transcripts and the genomic structures were determined. The cDNAs for the two genes encode predicted proteins of similar size (133 and 135 amino acids for NSCL-1 and NSCL-2, respectively) and structure. The carboxyl-terminal 75 amino acids of the two proteins contain the bHLH motif and differ from each other by only three conservative amino acid changes, while the amino-terminal portions are markedly divergent from each other. In addition to the similar protein structure, the genes have a similar genomic organization, suggesting a close evolutionary relationship. The 5'-regulatory regions of the two genes share some features (i.e. potential TATA, CCAAT, and GATA binding sites) but also differ significantly in their G+C content. NSCL-1 is relatively G+C-rich (63%) in the sequences upstream of transcription initiation and has multiple potential binding sites for transcription factors that bind to G+C-rich sequences (e.g. AP-2). NSCL-2 is relatively A+T-rich (63%) in this region and has a potential binding site for AP1. Studies of expression in normal tissues demonstrated expression of NSCL-1 and NSCL-2 in the developing central and peripheral nervous system, most likely in developing neurons. Additional Northern analysis studies in cell lines revealed expression of these genes in some cell lines derived from tumors with neural or neuroendocrine features such as neuroblastoma, PNET, and small cell lung cancer. NSCL-1 is expressed in a larger number of these cell lines. The differences in expression may parallel differences in developmental regulation.