Discovery, in vitro and in vivo Biology of c-mpl Ligand

Since the announcement of the discovery of thrombopoietin in 1994, a tremendous amount of research has determined that recombinant c-mpl ligand (ML) is capable of producing the biological effects of a Meg-CSF and thrombopoietin. Thrombopoietin's effects include the stimulation of primitive hematopoietic stem cells, megakaryocyte progenitor cells, megakaryocyte production and maturation and leading to the formation of platelets both in vitro and in vivo. Animal models of chemotherapy-induced thrombocytopenia have yielded data which fore-shadows a beneficial effect of thrombopoietin in clinical thrombocytopenia. The signaling mechanisms transducing thrombopoietin's actions are currently under research but in progenitor cells most likely involve modulation of the expression of genes regulated by the Jak-STAT signaling pathways, given throm-bopoietin's similarity to erythropoietin. Remnants of the Janus kinase signaling system appear to be active in the platelet and mediate enhanced platelet aggre-gation in response to platelet agonists upon stimulation of the c-mpl receptor with ML. The observation of enhanced platelet aggregation in vitro has not translated to enhanced thrombosis in relevant in vivo animal models. Preliminary clinical reports are returning clear evidence that the lineage-dominant effects of rHuMGDF on megakaryocytopoiesis observed in experimental settings are also holding true in the clinic.

Safety, pharmacokinetics, and pharmacodynamics of avoralstat, an oral plasma kallikrein inhibitor: phase 1 study

BACKGROUND

Avoralstat is a potent small-molecule oral plasma kallikrein inhibitor under development for treatment of hereditary angioedema (HAE). This first-in-human study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of avoralstat.

METHODS

This double-blind, placebo-controlled, ascending-dose cohort trial evaluated avoralstat single doses of 50, 125, 250, 500, and 1000 mg and multiple doses up to 2400 mg daily (100, 200, 400, and 800 mg every 8 h [q8 h] up to 7 days).

RESULTS

Avoralstat (n = 71) was generally well tolerated with no signals for a safety concern; there were no serious adverse events (AEs) or discontinuations due to AEs, and compared to placebo (n = 18), no notable difference in AEs. Four moderate severity AEs were reported in two subjects; syncope after a single 250 mg dose (one subject) and abdominal pain, back pain, and eczema after multiple doses of 800 mg avoralstat (one subject). For multiple-dose cohorts, the incidence of gastrointestinal AEs was highest at the 2400 mg/day dose. Elimination of avoralstat was bi-exponential with a terminal half-life of 12-31 h. Inhibition of plasma kallikrein was observed at all doses, and the degree of inhibition was highly correlated with avoralstat concentrations (R = 0.93). Mean avoralstat concentrations at doses ≥400 mg q8 h met or exceeded plasma kallikrein EC₅₀ values throughout the dosing interval.

CONCLUSION

Avoralstat was well tolerated, and drug exposure was sufficient to meet target levels for inhibition of plasma kallikrein. Based on these results, the 400 mg q8 h dose was selected for further evaluation in patients with HAE.

The emergency use authorization of peramivir IV: a view from the manufacturer

The 2009 H1N1 influenza pandemic prompted the US Food and Drug Administration (FDA) to issue an emergency use authorization (EUA) for the intravenous antiviral peramivir, an unapproved neuraminidase inhibitor (NAI) currently under development. Peramivir use was limited to patients for whom other NAI therapy had failed or in whom oral or inhalational drug absorption was believed to be unreliable. This introduced a patient selection bias that precluded safety and efficacy assessment. Despite the challenges and risks, there was a compelling public health need for an intravenous agent during the 2009 H1N1 pandemic.

Development of GnRH antagonists for prostate cancer: new approaches to treatment

Prostate cancer has become the most common cancer among American men and is second only to lung cancer as a cause of male cancer-related death. Several treatment options exist for different stages of prostate cancer including observation, prostatectomy, radiation therapy, chemotherapy, and hormone therapy. Hormone therapy has evolved from the use of estrogens to gonadotropin-releasing hormone (GnRH) agonists and recently, investigational GnRH antagonists. GnRH receptor agonists such as leuprolide, bruserelin and goserelin have been used for the treatment of prostate cancer. These agonists eventually cause the inhibition of lutenizing hormone production, which in turn causes a suppression of testosterone and dihydrotestosterone, on which continued growth of prostate cancer cells depend. Several comparative studies of leuprorelin administered as daily injections or monthly depot injections have been reported. Disease progression was prevented in more than 72% of men administered daily leuprorelin, and in 82% to 89% of those receiving monthly depots. Another synthetic GnRH analog, goserelin, has been studied in a similar population of men with daily injections producing partial responses in 60% to 80% of men with previously untreated prostate cancer. Abarelix, a peptide antagonist of GnRH receptor, is also being studied for the treatment of prostate cancer. The discovery and development of GnRH antagonists may provide an important advance for patients with prostate cancer. Clearly the studies described herein, as well as many others, outline an exciting era of research to define the optimal use of hormonal therapy in prostate cancer.

The prolonged hematologic effects of a single injection of PEG-rHuMGDF in normal and thrombocytopenic mice

A single injection of > or =10 microg/kg PEG-rHuMGDF in mice causes a dose-dependent increase in circulating platelets beginning on day 3 and peaking on days 5-6. The mean platelet volume and platelet distribution width at doses > or =100 microg/kg initially increase in a dose-dependent fashion and later decrease. However, the mean platelet volume does not change when platelets are incubated with PEG-rHuMGDF in vitro. The number of marrow megakaryocytes increases in a dose-dependent fashion as early as day 1 and peaks on day 3. Marrow megakaryocyte colony-forming units (CFU-Meg) do not increase on days 1-3 at a dose of 100 microg/kg (a dose that increases platelet numbers two- to threefold and may be clinically relevant), but the relative frequency of high ploidy megakaryocytes and the proportion of large marrow megakaryocytes (29-50 microm in diameter) increases. After a dose of 1,000 microg/kg the percentage of megakaryocytes in mitosis peaks at 24-48 hours and the percentage of megakaryocytes incorporating BrdU is maximal at 48 hours, the relatively delayed peak of BrdU incorporation most likely representing endomitosis. The relative frequency of type II and III megakaryocytes peaks on days 3 and 4, respectively. Pharmacokinetic analysis of PEG-rHuMGDF shows peak serum concentrations at 2-4 hours and a terminal half-life of 11.4+/-2.5 hours. A single injection of PEG-rHuMGDF ameliorates carboplatin-induced megakaryocytopenia and thrombocytopenia in a dose-response dependent fashion. In conclusion, a single injection of PEG-rHuMGDF increases megakaryocyte and platelet production in normal and myelo-suppressed mice.

Multicycle high-dose chemotherapy and filgrastim-mobilized peripheral-blood progenitor cells in women with high-risk stage II or III breast cancer: five-year follow-up

PURPOSE

To determine the safety and efficacy of multiple cycles of dose-intensive, nonablative chemotherapy in women with poor-prognosis breast cancer.

PATIENTS AND METHODS

Women with stage II breast cancer and 10 or more involved nodes or four or more involved nodes and estrogen receptor-negative tumors and women with stage III disease received three cycles of epirubicin 200 mg/m2 and cyclophosphamide 4 g/m2, with progenitor cell and filgrastim support every 28 days (n = 79) or 21 days (n = 20). Patients were reviewed at least twice yearly thereafter. Twenty-six patients had bone marrow and apheresis collections assessed for the presence of micrometastatic tumor cells.

RESULTS

Ninety-nine women (median age, 43 years; range, 24 to 60 years) were treated. Ninety-two completed all three cycles of chemotherapy. The major toxicity was severe, reversible myelosuppression that was more prolonged with successive cycles, and this did not differ between patients given treatment every 28 days and those treated every 21 days. Febrile neutropenia occurred in 176 (61%) of 287 cycles. Severe mucositis (grade 3 or 4) occurred in 23% of cycles but tended to be short-lived and was reversible. The cardiac ejection fraction fell by a median of 4% during treatment, and three patients developed evidence of cardiac failure after chemotherapy. Two patients (2%) died of acute toxicity. Three of 26 patients had evidence of circulating micrometastatic tumor cells. The actuarial distant disease-free and overall survival rates at 60-month follow-up were 64% (95% confidence interval [CI], 53% to 75%) and 67% (95% CI, 56% to 78%), respectively.

CONCLUSION

Multiple cycles of dose-intensive, nonablative chemotherapy is a feasible and safe approach. Disease control and survival are similar to those in other studies of myeloablative chemotherapy in poor-prognosis breast cancer. The regimen is being evaluated in a randomized trial of the International Breast Cancer Study Group.

Dose escalation study of carboplatin and cyclophosphamide with filgrastim support: a phase I study

This clinical trial was designed to explore dose escalation of carboplatin and cyclophosphamide when supported with filgrastim. Twenty-seven patients who had advanced solid tumors received up to six cycles of treatment; a total of 92 cycles of chemotherapy were delivered. Two control groups received standard-dose carboplatin (300 mg/m2) and cyclophosphamide (600 mg/m2), with and without filgrastim. Subsequently, the doses of both carboplatin and cyclophosphamide were increased simultaneously by 50% of the standard dose in sequential cohorts. Doses of up to 2.5 times the standard dose were explored. A final dose of carboplatin, 600 mg/m2, and cyclophosphamide, 1,500 mg/m2, was tested in 4 patients. The duration of neutropenia was brief, even at the highest dose levels. The mean duration of grade 3 or 4 neutropenia was 5.8 days at standard dose without filgrastim and 5.4 days at 2.5 times standard dose with filgrastim. More severe neutropenia was more prolonged at higher doses but remained brief in duration. The mean duration of neutropenia of less than 100 x 10(6)/l was 0.4 days at standard dose without filgrastim and 1.3 days at 2.5 times standard dose. There was no evidence of cumulative neutropenia over repeated cycles of treatment. In contrast, thrombocytopenia was both dose limiting and cumulative. The mean duration of grade 3 or 4 thrombocytopenia was 1.6 days at standard dose and 9.6 days at 2.5 times standard dose. An average of 2.3 platelet transfusions per cycle of treatment was required at the highest dose. Thrombocytopenia was worse with repetitive cycles of therapy. The mean duration of grade 3 or 4 thrombocytopenia was 2.2 days after the first cycle of chemotherapy and 7.8 days after cycle four. The maximum tolerated dose, as defined prospectively, was not reached but further dose escalation was not thought to be warranted because of the severity of thrombocytopenia. When supported with filgrastim, carboplatin and cyclophosphamide can be administered safely with substantially increased dose and acceptable toxicity.

Rapid hematopoietic recovery after multicycle high-dose chemotherapy: enhancement of filgrastim-induced progenitor-cell mobilization by recombinant human stem-cell factor

PURPOSE

To assess the mobilization potential and safety of recombinant human stem-cell factor (SCF) when coadministered with filgrastim to untreated women with poor-prognosis breast cancer.

PATIENTS AND METHODS

Eligible women had breast cancer with 10 or more positive axillary nodes, or estrogen receptor-negative tumor with 4 positive nodes, or stage III disease. Patients were randomized to receive SCF plus filgrastim or filgrastim alone. Filgrastim 12 microg/kg daily was administered for 6 days by continuous subcutaneous infusion. SCF was administered by daily subcutaneous injection at 5, 10, or 15 microg/kg concurrent with filgrastim for 7 days, or 10 microg/kg daily starting 3 days before filgrastim for a total of 10 days (SCF pretreatment). Apheresis was performed on days 5, 6, and 7 of filgrastim administration. Patients then had three cycles of epirubicin 200 mg/m2 and cyclophosphamide 4 g/m2 every 28 days, each supported by one third of the apheresis product.

RESULTS

Sixty-two women were treated. Greater yields occurred in patients who received SCF 10 microg/kg daily plus filgastim than those who received filgrastim alone (P=.013 for CD34+ cells; P=.07 for granulocyte-macrophage colony-forming cells [GM-CFCs]). The difference was more marked with SCF-pretreatment than concurrent SCF. Fewer aphereses were required to reach the predetermined target of peripheral-blood progenitor/stem cells (PBPCs) in women who received SCF. SCF was generally well tolerated. Hematologic recovery was rapid after each of the three cycles of chemotherapy. There was no difference in recovery between the different treatment groups.

CONCLUSION

Mobilization of PBPCs by filgrastim is significantly enhanced by coadministration of SCF, and commencing SCF before filgrastim can optimize this effect. SCF has the potential to reduce the number of aphereses required to collect a target number of PBPCs.

Enhanced levels and enhanced clonogenic capacity of blood progenitor cells following administration of stem cell factor plus granulocyte colony-stimulating factor to humans

Administration of hematopoietic growth factors is being used increasingly to obtain populations of blood progenitor/stem cells (PBPC) for clinical transplantation. Here we examined the effect of combining stem cell factor (SCF ) and granulocyte colony-stimulating factor (G-CSF ) versus G-CSF alone in a randomized clinical study involving 62 women with early-stage breast cancer. In the first patient cohorts, escalating doses of SCF were administered for 7 days with concurrent G-CSF administration. At baseline, levels of progenitor cells in the bone marrow or blood were comparable in the different patient groups. As with administration of G-CSF alone, the combination of SCF plus G-CSF did not alter the wide variation in levels of PBPC observed between individuals and did not alter the selective nature of PBPC release, with preferential release of day-14 granulocyte-macrophage colony-stimulating factor (GM-CFC) versus day-7 GM-CFC. However, SCF acted to sustain the levels of PBPC after cessation of growth factor treatment; levels of PBPC were elevated 100-fold at later timepoints compared with G-CSF alone. In addition, the maximum levels of PBPC observed were increased approximately fivefold at day 5 of growth-factor administration. The increased levels of PBPC resulted in significantly increased levels of PBPC obtained by leukapheresis. In a subsequent patient cohort, 3-days pretreatment with SCF was introduced and followed by 7 days concurrent SCF plus G-CSF. The 3-days pretreatment with SCF resulted in an earlier wave of PBPC release in response to commencement of G-CSF. In addition, maximum PBPC levels in blood and PBPC yield in leukapheresis products were further increased. Unexpectedly however, SCF pretreatment resulted in progenitor cells with enhanced self-generation potential. Recloning assays documented the ability of approximately 30% of primary granulocyte-macrophage (GM) colonies from control cell populations to generate secondary GM colonies (n = 1,106 primary colonies examined). In contrast approximately 90% of GM colonies from PBPC after SCF pretreatment generated secondary clones and 65% generated secondary colonies. The action of SCF was not explicable in terms of altered SCF, GM-CSF, or G-CSF responsiveness, but SCF pretreatment was associated with maximum serum SCF levels at the time G-CSF was commenced. These results show that PBPC populations mobilized by different growth factor regimens can differ in their functional properties and caution against solely considering number of harvested progenitor cells without regard to their function.

Peripheral blood progenitor cell mobilization using stem cell factor in combination with filgrastim in breast cancer patients

The safety and optimal dose and schedule of stem cell factor (SCF) administered in combination with filgrastim for the mobilization of peripheral blood progenitor cells (PBPCs) was determined in 215 patients with high-risk breast cancer. Patients received either filgrastim alone (10 microg/kg/d for 7 days) or the combination of 10 microg/kg/d filgrastim and 5 to 30 microg/kg/d SCF for either 7, 10, or 13 days. SCF patients were premedicated with antiallergy prophylaxis. Leukapheresis was performed on the final 3 days of cytokine therapy and, after high-dose chemotherapy and infusion of PBPCs, patients received 10 microg/kg/d filgrastim until absolute neutrophil count recovery. The median number of CD34+ cells collected was greater for patients receiving the combination of filgrastim and SCF, at doses greater than 10 microg/kg/d, than for those receiving filgrastim alone (7.7 v 3.2 x 10(6)/kg, P < .05). There were significantly (P < .05) more CD34+ cells harvested for the 20 microg/kg/d SCF (median, 7.9 x 10(6)/kg) and 25 microg/kg/d SCF (median, 13.6 x 10(6)/kg) 7-day combination groups than for the filgrastim alone patients (median, 3.2 x 10(6)/kg). The duration of administration of SCF and filgrastim (7, 10, or 13 days) did not significantly affect CD34+ cell yield. Treatment groups mobilized with filgrastim alone or with the cytokine combination had similar hematopoietic engraftment and overall survival after PBPC infusion. In conclusion, the results of this study indicate that SCF therapy enhances CD34+ cell yield and is associated with manageable levels of toxicity when combined with filgrastim for PBPC mobilization. The combination of 20 microg/kg/d SCF and 10 microg/kg/d filgrastim with daily apheresis beginning on day 5 was selected as the optimal dose and schedule for the mobilization of PBPCs.

Mechanism of action and clinical trials of Mpl ligand

Mpl ligand is the hematopoietic growth factor responsible for regulating the production of platelets. Since its discovery just 3 years ago, it has provided both unique insights into megakaryocytopoiesis and the means to stimulate platelet production in numerous clinical situations. In animals deficient in Mpl ligand, the number of megakaryocytes and platelets decreases by more than 80%. In addition to having an effect on the megakaryocyte lineage, Mpl ligand supports the growth of stem cells, multipotential cells, and erythroid precursors. The endogenous Mpl ligand, thrombopoietin, is produced in the liver and kidneys, and circulating levels appear to be regulated primarily by the mass of platelets and megakaryocytes, which bind and catabolize Mpl ligand. The clinical utility of recombinant Mpl ligands is currently under intense investigation. Early results have demonstrated a marked stimulation of megakaryocyte and platelet production with no apparent adverse effects. In patients with cancer who are treated with chemotherapy, the duration of thrombocytopenia was shorter in patients treated with Mpl ligand than in those receiving placebo. The eventual role of Mpl ligand in clinical practice will be determined by the results of many ongoing clinical studies.

Multilineage mobilization of peripheral blood progenitor cells in humans following administration of PEG-rHuMGDF

The most important physiological regulator of megakaryocytopoiesis is the ligand for the c-mpl receptor (thrombopoietin/megakaryocyte growth and development factor, MGDF). We examined the effect of pegylated-recombinant human MGDF (PEG-rHuMGDF): patients received PEG-rHuMGDF at doses of 0.03, 0.1, 0.3 or 1.0 microg/kg/d or placebo for 10d maximum in a double-blinded randomized study. There was a dose-dependent elevation in circulating platelet counts but no alteration in erythrocyte or total leucocyte counts. The number of bone marrow megakaryocytes was increased approximately 2-fold. The frequency of bone marrow progenitor cells was not altered. In contrast, both to the bone marrow results and to published pre-clinical data, there was a dose-dependent mobilization into the blood of progenitor cells of multiple cell lineages. Increased levels of Meg-CFC (maximum increase 30-fold), day 7 and day 14 GM-CFC and BFU-E were demonstrated at doses of 0.3 and 1.0 microg/kg/d PEG-rHuMGDF. At 0.1 microg/kg/d, mobilization of Meg-CFC alone occurred in two-thirds of patients. Maximum blood levels of progenitor cells occurred at day 12. Thus, administration of PEG-rHuMGDF to humans resulted in mobilization of progenitor cells of multiple lineages despite its 'lineage-specific' activity on mature cell development.

Systemic hematologic effects of PEG-rHuMGDF-induced megakaryocyte hyperplasia in mice

PEG-rHuMGDF injected daily in normal mice causes a rapid dose-dependent increase in megakaryocytes and platelets. At the same time that platelet numbers are increased, the mean platelet volume (MPV) and platelet distribution width (PDW) can be either decreased, normal, or increased depending on the dose and time after administration. Thus, PEG-rHuMGDF at a low dose causes decreases in MPV and PDW, MGDF at an intermediate dose causes an initial increase followed by a decrease in MPV and PDW, and PEG-rHuMGDF at higher doses causes an increase in MPV and PDW followed by a gradual normalization of these platelet indices. In addition to the expected thrombocytosis after 7 to 10 days of daily injection of high doses of PEG-rHuMGDF, a transient decrease in peripheral red blood cell numbers and hemoglobin is noted accompanied in the bone marrow by megakaryocytic hyperplasia, myeloid hyperplasia, erythroid and lymphoid hypoplasia, and deposition of a fine network of reticulin fibers. Splenomegaly, an increase in splenic megakaryocytes, and extramedullary hematopoiesis accompany the hematologic changes in the peripheral blood and marrow to complete a spectrum of pathologic features similar to those reported in patients with myelofibrosis and megakaryocyte hyperplasia. However, all the PEG-rHuMGDF-initiated hematopathology including the increase in marrow reticulin is completely and rapidly reversible upon the cessation of administration of PEG-rHuMGDF. Thus, transient hyperplastic proliferation of megakaryocytes does not cause irreversible tissue injury. Furthermore, PEG-rHuMGDF completely ameliorates carboplatin-induced thrombocytopenia at a low-dose that does not cause the hematopathology associated with myelofibrosis.

Megakaryocyte growth and development factor. Analyses of in vitro effects on human megakaryopoiesis and endogenous serum levels during chemotherapy-induced thrombocytopenia

The present study shows that recombinant human megakaryocyte growth and development factor (r-HuMGDF) behaves both as a megakaryocyte colony stimulating factor and as a differentiation factor in human progenitor cell cultures. Megakaryocyte colony formation induced with r-HuMGDF is synergistically affected by stem cell factor but not by interleukin 3. Megakaryocytes stimulated with r-HuMGDF demonstrate progressive cytoplasmic and nuclear maturation. Measurable levels of megakaryocyte growth and development factor in serum from patients undergoing myeloablative therapy and transplantation are shown to be elaborated in response to thrombocytopenic stress. These data support the concept that megakaryocyte growth and development factor is a physiologically regulated cytokine that is capable of supporting several aspects of megakaryopoiesis.

Filgrastim in patients with chemotherapy-induced febrile neutropenia. A double-blind, placebo-controlled trial

OBJECTIVE

To determine if filgrastim (recombinant human methionyl granulocyte colony-stimulating factor) used in addition to standard inpatient antibiotic therapy accelerated recovery from infection associated with chemotherapy-induced neutropenia.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Hematology and oncology wards of four teaching hospitals.

PATIENTS

218 patients with cancer who had fever (temperature > 38.2 degrees C) and neutropenia (neutrophil count < 1.0 x 10(9)/L) after chemotherapy.

INTERVENTION

Patients were randomly assigned to receive filgrastim (12 micrograms/kg of body weight per day) (n = 109) or placebo (n = 107) beginning within 12 hours of empiric therapy with tobramycin and piperacillin. Patients received treatment and remained in the study until the neutrophil count was greater than 0.5 x 10(9)/L and until 4 days without fever (temperature < 37.5 degrees C) had elapsed.

MEASUREMENTS

Days of neutropenia and fever and days in the study (hospitalization); time to resolution of fever and febrile neutropenia; and frequency of the use of alternative antibiotics.

RESULTS

Compared with placebo, filgrastim reduced the median number of days of neutropenia (3.0 compared with 4.0 days of a neutrophil count of < 0.5 x 10(9)/L; P = 0.005) and the time to resolution of febrile neutropenia (5.0 compared with 6.0 days; P = 0.01) but not days of fever (3.0 days for both groups). The frequency of the use of alternative antibiotics was similar in the two groups (46% compared with 41%; P = 0.48). The median number of days patients were hospitalized while on study was the same (8.0 days; P = 0.09); however, filgrastim decreased the risk for prolonged hospitalization (> 11 days, 4th quartile) by half (relative risk, 2.1 [95% CI, 1.1 to 4.1]; P = 0.02). In exploratory subset analyses, filgrastim appeared to provide the greatest benefit in patients with documented infection and in patients presenting with neutrophil counts of less than 0.1 x 10(9)/L.

CONCLUSIONS

Filgrastim treatment used with antibiotics at the onset of febrile neutropenia in patients with cancer who have received chemotherapy accelerated neutrophil recovery and shortened the duration of febrile neutropenia.

Phase II study of autologous filgrastim (G-CSF)-mobilized peripheral blood progenitor cells to restore hemopoiesis after high-dose chemotherapy for lymphoid malignancies

The hemopoietic growth factor filgrastim (r-metHu G-CSF) stimulates granulopoiesis after autologous BMT and can also be used as a peripheral blood progenitor cell (PBPC)-mobilizing agent. Rapid platelet recovery follows the addition of filgrastim-mobilized PBPC to autologous BMT. We have now studied 29 adults with malignant lymphoma, Hodgkin's disease or ALL to assess the ability of filgrastim-mobilized PBPC to rapidly and durably restore hemopoiesis without bone marrow (BM) infusion. Patients with a high yield of PBPC from three leukaphereses, defined as > 30 x 10(4)/kg GM-CFC, were eligible for PBPC transplant without BM. Patients with a low yield of GM-CFC received both PBPC and BM infusion. After filgrastim therapy 12 or 24 micrograms/kg/day by continuous sc infusion for 6 or 7 days, a high yield was obtained in 11 of 29 patients. Kinetics of recovery of both the platelet and neutrophil counts were more rapid in the high yield group than in the low yield group. The platelet count recovered to > 20 x 10(9)/l at a median of 9 days, to > 50 x 10(9)/l at 11 days and the neutrophil count to > 0.5 x 10(9)/l at 9 days in the high yield group compared with 12 days, 37 days and 10 days, respectively, in the low yield group (p = 0.028, p < 0.001 and p = 0.027). Fewer platelet transfusions were required in the high yield group (median 11 vs 29.5 units, p = 0.021).(ABSTRACT TRUNCATED AT 250 WORDS)

High dose busulphan/cyclophosphamide for autologous bone marrow transplantation is associated with minimal non-hemopoietic toxicity

We retrospectively reviewed the regimen-related toxicity associated with busulphan (1 mg/kg orally QID days -7 to -4) and cyclophosphamide (60 mg/kg IV days -3 and -2) (Bu/Cy) chemotherapy in 69 consecutive patients who underwent autologous bone marrow transplantation (ABMT). Twenty-four patients received bone marrow (BM) alone, 22 received BM plus post-transplant granulocyte-colony stimulating factor (G-CSF) and 23 received peripheral blood progenitor cells (PBPC) +/- BM plus post-transplant G-CSF. Toxicity was scored using the criteria of Bearman. Grade II and III toxicities included mucosa (38%), liver (8%), central nervous system (5%), kidney (5%), heart (3%), pericardium (2%), bladder (2%) and lung (2%). There were five treatment related deaths (7%) from pneumonitis (2) and veno-occlusive disease, pulmonary hemorrhage and sepsis (1 each). Post-transplant G-CSF (+/- PBPC) resulted in a trend (p = 0.07) towards a reduction in post-transplant stomatitis, but did not impact on the already low incidence of other organ toxicities. As Bu/Cy for ABMT is associated with minimal non-hemopoietic toxicity, the addition of other cytotoxic agents is justified in an attempt to augment the anti-tumour effect of this conditioning regimen.

Transplantation of mobilized peripheral blood stem cells: role of filgrastim

Autologous bone marrow transplantation, although successful, is limited in the rate of hematopoietic recovery achieved. Myeloablative chemotherapy results in prolonged pancytopenia with standard autologous bone marrow support. High-dose myelosuppressive chemotherapy results in severe but short-term pancytopenia, and hematopoietic recovery is routine without cellular support. Cellular support becomes necessary when multiple-cycle, severely myelosuppressive regimens are used because of the cumulative stem cell damage and unacceptably long duration of severe pancytopenia. Peripheral blood progenitor cells (PBPCs) may be used as cellular support, and colony-stimulating factors with or without chemotherapy are currently the most potent available PBPC-mobilizing tools. Filgrastim (rmethG-CSF) has been shown to enhance the number of PBPCs for harvest in both cancer patients and normal donors. When Filgrastim is used in conjunction with chemotherapy, there appears to be greater PBPC mobilization, which seems to be dependent on dose and schedule of chemotherapy as well as the type of chemotherapeutic agent used. Platelet recovery has been shown to be more rapid when PBPCs are used compared with historical controls given autologous bone marrow infusions. It may be concluded that PBPC transplantation is useful supportive care following myeloablative chemotherapy.

Assessment of proliferative responses to granulocyte-macrophage colony-stimulating factor (GM-CSF) in acute myeloid leukaemia using a fluorescent ligand for the nucleoside transporter

Nucleoside transporter expression has been linked to proliferation in a variety of haemopoietic cell types. Granulocyte-macrophage colony-stimulating factor (GM-CSF) was given for 72 h before commencing chemotherapy in 15 patients with relapsed or refractory acute myeloid leukaemia (AML) and in 11 patients serial bone marrows were taken for measurement of [3H]thymidine labelling index, Ki-67 positivity and maximal binding of 5-(SAENTA-x8)-fluorescein, a flow cytometry ligand which enumerates nucleoside transporter sites. GM-CSF caused proliferation of marrow myeloblasts in eight of 11 patients, while in three patients there was no change in proliferative indices. The expression of nucleoside transporters increased up to 4-fold in the myeloblasts from the patients showing a proliferative response to GM-CSF but there was no increase in transporters on the myeloblasts from the three non-responding patients. A close correlation was found between the fold increase in nucleoside transporter expression and the fold increase in labelling index of marrow myeloblasts (r = 0.86, n = 9, p < 0.01). In one patient with acute megakaryoblastic leukemia, GM-CSF caused parallel increases in labelling index, Ki-67 positivity and numbers of nucleoside transporters on peripheral blood blast cells. Thus induction of proliferation by cytokine increases the expression of nucleoside transporters on leukaemic myeloblasts studied in serial samples from the same source (bone marrow or blood). The suitability of 5-(SAENTA-x8)-fluorescein for two colour flow cytometric analysis allows the rapid enumeration of nucleoside transporters in the myeloblast compartment of heterogeneous marrow samples.

Donor leucocyte infusions after chemotherapy for patients relapsing with acute leukaemia following allogeneic BMT

Four patients with acute myeloid leukaemia relapsed within 6 months of allogeneic BMT. Three patients were treated with cytosine arabinoside and amsacrine while the fourth received no chemotherapy. All patients received infusions of leucocytes obtained by repeated leukapheresis from the original bone marrow donor. Three patients developed GVHD requiring immunosuppressive therapy. One of these achieved a complete remission which has been sustained for more than 1 year with 100% donor haematopoiesis. The other patients died with persistent leukaemia 45-134 days after the infusions of donor cells. We conclude that the addition of marrow donor leucocytes to salvage chemotherapy may produce durable remissions in patients with acute myeloid leukaemia relapsing after BMT and that this may be due to a graft-versus-leukaemia effect.

Primary cerebral lymphoma: an argument for the use of adjunctive systemic chemotherapy

Eleven patients with primary cerebral lymphoma were treated at a single institution over a 5 year period. Patient characteristics were typical of this rare disease. One patient died prior to receiving treatment and of the remaining 10, all received cranial irradiation and in addition, five received systemic cyclophosphamide, adriamycin, vincristine and prednisolone (CHOP) chemotherapy. Of the six patients who are alive and disease-free, five received the combined modality therapy. The median survival for those patients receiving cranial irradiation alone was 18 months and for the combined modalities was 25+ months. Combination systemic chemotherapy, in addition to cerebral irradiation, may convey a survival benefit in patients with primary cerebral lymphoma but this requires further investigation with multicentre, prospective randomized trials.

Prior chemotherapy does not prevent effective mobilisation by G-CSF of peripheral blood progenitor cells

In this study we demonstrate that the hemopoietic growth factor, G-CSF successfully mobilised progenitor cell populations into the peripheral blood in a population of patients despite intensive pretreatment with chemotherapy. Administration of G-CSF increased the numbers of peripheral blood progenitor cells (PBPC) by a median of 76-fold above basal levels. Maximal levels of PBPC were observed on days 5 and 6 after G-CSF treatment. In two patients a second cycle of G-CSF mobilised PBPC to levels comparable with those seen after the first cycle of G-CSF treatment. An earlier hemopoietic cell population (pre-CFC's) was also mobilised with levels increased up to 50-fold above basal levels. Using a standard mononuclear cell leukapheresis technique the PBPC were collected extremely efficiently (essentially 100%) and could be further successfully enriched by separation using a Ficoll gradient. For patients who underwent the optimal collection protocol (i.e. leukapheresis on days 5, 6 and 7) a total of 32 +/- 6 x 10(4) GM-CFC kg-1 were collected. The ability to mobilise PBPC using G-CSF alone and to successfully and efficiently harvest these cells has important implications for the future of transplantation and high dose chemotherapy procedures.

Delay by internists in obtaining diagnostic biopsies in patients with suspected cancer

OBJECTIVE

To investigate the degree and type of delays in performing diagnostic biopsies in medical patients with suspected malignancy.

DESIGN

Retrospective survey of clinical histories of patients referred between January 1985 and March 1989.

SETTING

Inner city teaching hospital internal medicine (non-oncologic) services.

PATIENTS

Patients with gastrointestinal and lung cancers, adenocarcinoma of unknown primary site, and lymphomas were referred as inpatients by internists. Two hundred fifty-five patients were eligible, and 177 were evaluable.

MAIN OUTCOME MEASURES

The number, type, and results of tests done before and after biopsy were analyzed.

RESULTS

In 67% of patients the biopsied lesion was detected by the second day of evaluation; however, there was an 8- to 10-day delay before a biopsy was done. This delay was consistent across the four malignancy groups studied. Although logistic and other unavoidable delays occurred in 40% of the cases, in 60% delays could only be attributed to continued, frequently low yield, noninvasive tests. An average of 3.3 tests were made per patient, with only 24% leading to a definitive biopsy.

CONCLUSION

Because of the performance of many other tests, a substantial delay exists in proceeding to biopsy during the diagnosis of cancer by internists.

Effect of peripheral-blood progenitor cells mobilised by filgrastim (G-CSF) on platelet recovery after high-dose chemotherapy

The haemopoietic growth factor granulocyte colony-stimulating factor (G-CSF; filgrastim) substantially shortens the period of severe neutropenia that follows high-dose chemotherapy and autologous bone-marrow infusion by stimulating granulopoiesis. Filgrastim also increases numbers of circulating progenitor cells. We have studied the ability of filgrastim to mobilise peripheral-blood progenitor cells and assessed their efficacy when infused after chemotherapy on recovery of neutrophil and platelet counts. 17 patients with non-myeloid malignant disorders received filgrastim (12 micrograms/kg daily for 6 days) by continuous subcutaneous infusion. Numbers of granulocyte-macrophage progenitors in peripheral blood increased a median of 58-fold over pretreatment values, and numbers of erythroid progenitors increased a median of 24-fold. Three leucapheresis procedures collected a mean total of 33 (SEM 5.7) x 10(4) granulocyte-macrophage progenitors per kg body weight. After high-dose chemotherapy in 14 of the patients (busulphan and cyclophosphamide), these cells were used to augment autologous bone-marrow rescue and post-transplant filgrastim treatment. Platelet recovery was significantly faster in these patients than in controls who received the same treatment apart from the infusion of peripheral-blood progenitors; the platelet count reached 50 x 10(9)/l a median of 15 days after infusion of haemopoietic cells in the study patients compared with 39 days in controls (p = 0.0006). The accelerated neutrophil recovery associated with filgrastim treatment after chemotherapy was maintained. This method may be widely applicable to aid both neutrophil and platelet recovery after high-dose chemotherapy; it will allow investigation of peripheral-blood progenitor-cell allotransplantation.

Pilot study of escalating doses of carboplatin and cyclophosphamide in patients with advanced cancer

In all, 18 patients with histologically proven advanced cancer received 400 mg/m2 carboplatin (CBDCA) plus 800 mg/m2 cyclophosphamide (level 1), and 14 others received 550 mg/m2 CBDCA plus 1100 mg/m2 cyclophosphamide (level 2). A maximum of six cycles was given if a response occurred. The dose-limiting toxicity was myelosuppression, with neutropenia being more marked than thrombocytopenia. At level 2, patients experiencing a febrile-neutropenic event showed a mean 24-h urinary creatinine clearance value of 1.1 ml/s (95% confidence limits 0.8-1.4 ml/s), whereas in those who remained afebrile it was 1.7 ml/s (95% confidence limits, 1.3-2.0 ml/s). This difference was significant (P less than 0.01). Other toxicities were only mild. Creatinine clearance is a predictor of febrile episodes after treatment with high doses of CBDCA and cyclophosphamide. We are now conducting a study using human granulocyte colony-stimulating factor to reduce the incidence of neutropenia with escalating doses of these drugs in an attempt to prevent febrile events.

Recombinant alpha-2b interferon in patients with malignant carcinoid tumour

Seventeen patients with malignant carcinoid tumour, ten of whom had the malignant carcinoid syndrome, were treated with recombinant alpha-2b interferon by subcutaneous injection (3 MU per dose) three times per week for a median of 12 weeks (range 4-48). No objective tumour responses were observed; however, there was a greater than 50% reduction in 24-hour urinary 5-hydroxyindolacetic acid (5-HIAA) excretion in four of ten patients (40%) with elevated pretreatment levels. Five of ten patients (50%) with flushing, five of seven patients (71%) with diarrhoea and both patients with wheezing experienced relief of symptoms. Three of four patients (75%) with weight loss as their only problem experienced weight gain. Responses occurred within the first eight weeks of treatment, but were generally of short duration. Toxicity occurred in all patients, and consisted mainly of fever, chills, anorexia, fatigue and weight loss. Four patients ceased therapy due to toxic reactions. Although interferon has activity against carcinoid tumours, its benefits are short-lived and toxicity limits its use with increasing dose. Patients with carcinoid syndrome appear to achieve the best therapeutic response, and it is likely that low doses (9-20 million IU weekly) are as effective as higher doses (36-72 million IU weekly).

Chronic myeloid leukaemia treated by allogeneic bone marrow transplantation from histocompatible sibling donors--an invariably fatal malignancy rendered highly curable

Twenty-eight patients aged 16-50 years with chronic myeloid leukaemia (CML) underwent allogeneic bone marrow transplantation (BMT) using human leukocyte antigen (HLA)-identical sibling donors. Of the 28 patients, 21 were in chronic phase, five were in accelerated phase and two were in blast phase at the time of BMT. Twenty-three of the patients survived more than 63-2187 days after BMT, 21 in continuous complete remission and two with haematologic relapse of CML. Two patients died of interstitial pneumonitis and one died of relapsed CML, cerebral aspergillosis and cytomegalovirus enterocolitis. The overall probability of survival at six years was 78% +/- 9% (mean +/- standard error) and of disease free survival 66 +/- 11%. For patients transplanted in chronic phase, the survival probability was 90 +/- 6%, while all of the patients undergoing BMT in chronic phase within the first year after diagnosis were alive with a relapse-free survival of 88 +/- 12%. The actuarial probability of occurrence of acute graft-versus-host disease (GVHD) was 57 +/- 9%, while for Grades II and III GVHD it was 28 +/- 9%. Chronic GVHD occurred in 18 of 25 patients at risk. The majority of patients had a Karnofsky performance score at latest follow-up of at least 90% (range 50-100). We conclude that allogeneic BMT is effective, curative therapy for CML and that BMT performed earlier in the natural history of the disease is associated with the best outcome.

Pharmacokinetics and toxicity of two schedules of high dose epirubicin

Epirubicin, a stereoisomer of doxorubicin, is reported to have equal antitumor activity with lower cardiac and systemic toxicity. Recently the maximum tolerated dose of this drug has been revised upwards with reported increased response rates. However, the pharmacokinetics of epirubicin at high doses have never been reported. Accordingly, this study was designed to evaluate the pharmacokinetics of epirubicin when administered as either a 15-min i.v. bolus or a 6-h i.v. infusion in a phase I study at high doses. Nineteen patients with a variety of malignancies were given a total of 52 cycles of epirubicin at doses of 90 to 150 mg/m2 given once every 3 weeks. The maximum tolerated dose was 150 mg/m2 epirubicin given either as a bolus or as an infusion. The major dose-limiting toxicity was neutropenia. Interpatient variation occurred in the pharmacokinetics at each dose level but overall there were dose-dependent pharmacokinetics. This was manifested as a disproportionate increase in plasma levels and areas under the curve as the epirubicin dose was increased from 90 to 150 mg/m2. The pharmacokinetics of epirubicin could best be described by an open two-compartment model. Peak plasma concentrations were attained at a median of 12 min following the bolus injection and concentrations approached the steady state within a median of 55 min following the start of the 6-h infusion. Administration of the 150 mg/m2 dose over the 6 h compared to the bolus administration was associated with a 92% decrease in peak concentration from 3088 +/- 1503 to 234 +/- 126 ng/ml. This was not associated with an appreciable change in hematological or nonhematological toxicities. The median distribution half-life was 10 min and the median elimination half-life was 42.0 h. The cumulative renal excretion of the parent compound accounted for less than 2% of the administered dose. The major metabolites in both plasma and urine samples were 4'-O-beta-D-glucuronyl-4'-epidoxorubicin, 13-S-dihydro-4'-epidoxorubicin, and 4'-O-beta-D-glucuronyl-13-S-dihydro-4'-epidoxorubicin. This study demonstrates that a 135 mg/m2 bolus infusion given on a 3-weekly schedule is an appropriate initial dose for further clinical studies.

Combination chemotherapy as single modality therapy for stage IE and IIE thyroid lymphoma

Three women presented with malignant thyroid lymphoma (stage IE and IIE) that was associated with Hashimoto's thyroiditis. Each patient was treated with combination chemotherapy (two patients received cyclophosphamide/adriamycin/vincristine/prednisolone, one patient received methotrexate/adriamycin/cyclophosphamide/vincristine/prednisolone/ble omy cin) as the primary mode of therapy. One patient underwent incomplete excisional surgery and received chemotherapy. A complete clinical and radiological remission was achieved in all patients, in spite of evidence of extensive extrathyroidal invasion in two patients. The chemotherapy was well-tolerated, producing minimal toxicity. All the patients are alive and remain free of tumour recurrence 26 to more than 38 months after diagnosis. These results suggest that combination chemotherapy can be employed successfully as a single modality treatment for stage IE and IIE thyroid lymphomas, even when significant extrathyroidal invasion is present. The treatment of thyroid lymphoma is reviewed with emphasis on the potential role for chemotherapy as the primary modality.

Granulocyte colony-stimulating factor and neutrophil recovery after high-dose chemotherapy and autologous bone marrow transplantation

Granulocyte colony-stimulating factor (G-CSF) was administered by continuous subcutaneous infusion to 15 patients with non-myeloid malignancies treated by high-dose chemotherapy and autologous bone marrow infusion. G-CSF was given at variable dosage based on neutrophil count. Sustained serum levels of G-CSF were achieved. Neutrophil recovery was accelerated in G-CSF treated patients compared with 18 historical controls and exceeded 0.5 x 10(9)/l at a mean of 11 days after marrow infusion compared with 20 days for controls, a significant difference. This reduction led to significantly fewer days of parenteral antibiotic therapy, 11 versus 18 days in controls, and less isolation in reverse-barrier nursing, 10 versus 18 days.

High-dose chemotherapy with busulphan and cyclophosphamide and bone-marrow transplantation for drug-sensitive malignancies in adults: a preliminary report

The technique of high-dose chemotherapy and bone-marrow transplantation takes advantage of any potential dose-response effect in the treatment of cancer and the ability of infused marrow to circumvent severe myelotoxicity. We report our initial experience of 20 high-dose chemotherapy procedures with busulphan and cyclophosphamide as the treatment regimen. Autologous (14 patients), human leukocyte antigen-matched, sibling-allogeneic (five patients) and identical-twin (one patient) transplantations were performed in patients with leukaemias (12 patients), lymphomas (seven patients) or a germ-cell tumour (one patient). One in-hospital and one late death occurred as a result of the toxicity of high-dose chemotherapy. All evaluable patients demonstrated bone-marrow engraftment and became independent of blood transfusions. Five of six patients who were treated in partial remission or relapse obtained a complete remission. Seven patients have relapsed. Eleven patients currently are alive and disease-free and nine patients have returned to their full-time occupations. High-dose chemotherapy can be undertaken with an over-all morbidity that is similar to that which is experienced during the induction chemotherapy of acute leukaemia.

Evidence for a novel in vivo control mechanism of granulopoiesis: mature cell-related control of a regulatory growth factor

As part of phase I/II clinical trials of granulocyte colony-stimulating factor (G-CSF), the pharmacokinetics was studied. To determine the optimal way of abrogating the neutropenia caused by melphalan, patients received G-CSF and melphalan on several schedules. The half-life (t 1/2) of elimination of G-CSF was in the range 1.3 to 4.2 hours and was prolonged at higher doses, suggesting that one clearance mechanism becomes saturated at doses greater than 10 micrograms/kg, When a continuous subcutaneous (SC) infusion was administered for five days, a rapid reduction in serum G-CSF levels occurred during the last two days of the infusion, indicating that an additional clearance mechanism was induced. When a continuous infusion of G-CSF was administered after melphalan, serum G-CSF levels remained constant for a longer period of time but did decrease during the second phase of a biphasic neutrophil response. In another clinical trial, G-CSF was administered after high-dose chemotherapy and autologous bone marrow transplantation (ABMT). In these patients, the G-CSF levels did not decrease while the patients were neutropenic. These results show that increased neutrophil levels are associated with increased clearance of G-CSF. This may be one of the negative feedback mechanisms involved in maintaining neutrophil homeostasis in normal and disease states.

Hashimoto's disease, thyroid lymphoma and splenic atrophy

An elderly woman is described who developed Hashimoto's thyroiditis and, subsequently, thyroid lymphoma more than 15 years after the onset of splenic atrophy. This case supports the concept that splenic atrophy predisposes to the development of autoimmune thyroid disease. The relationship between splenic atrophy and autoimmune thyroid disease is reviewed.

Hemodynamic and plasma renin responses to treatment of a renal arteriovenous malformation

We report a case of a right renal arteriovenous malformation with high output cardiac failure and hypertension which was cured by nephrectomy. Hemodynamic findings pre- and post-operatively are presented. Plasma renin activity (PRA), both from peripheral venous and renal vein samples, was assessed. The fall in PRA associated with nephrectomy lends support to the suggestion that the renin-angiotensin system plays a role in the hypertension in these patients.

Non-Hodgkin's lymphoma of the stomach: a prospective pilot study of surgery plus chemotherapy in early and advanced disease

A prospective pilot study of 23 patients with non-Hodgkin's lymphoma involving the stomach was undertaken to assess the efficacy of surgical resection followed by chemotherapy with adjuvant cyclical cyclophosphamide, vincristine, and prednisolone (CVP) in early stage disease, and cyclical cyclophosphamide, vincristine, prednisolone, and doxorubicin (CHOP) in advanced disease. One of 18 evaluable patients died postoperatively; 17 of 18 completed therapy and are alive and disease-free at a median follow-up of 41 months after surgery (range, 5 to 111 months), including four patients with stage IV disease who remain in complete remission 19 to 47 months after surgery. There was one postoperative death, giving an actuarial survival rate of 94% in the study group. Three of five inoperable patients were treated with CHOP, with two achieving complete remission. Two untreated patients died. Overall actuarial disease-free survival was 82.6%. Surgical resection plus chemotherapy is capable of producing long-term remission and cure in both localized and advanced non-Hodgkin's lymphoma of the stomach. Intensive supportive care plus chemotherapy may salvage a proportion of patients with inoperable tumors.

Fever as an adverse reaction to carbamazepine

Two middle-aged women developed fever and abnormal liver function tests while taking carbamazepine. In one case the fever recurred following drug challenge. There are possible links to the known immune-related effects of the drug. Carbamazepine should be considered as a cause if fever or cholestasis develops in any person taking the drug.