Clinical benefit in patients with metastatic bone disease: results of a phase 3 study of denosumab versus zoledronic acid.

BACKGROUND: Patients with metastatic bone disease are living longer in the metastatic stage due to improvements in cancer therapy, making strategies to prevent the aggravation of bone disease and its complications, such as skeletal-related events (SREs) and pain, increasingly important. PATIENTS AND RESULTS: In this phase 3 trial in patients with advanced cancer (excluding breast and prostate cancer) or multiple myeloma, denosumab reduced the risk of radiation to bone by 22% relative to zoledronic acid (P = 0.026), prevented worsening of pain and pain interference (2-point increase in Brief Pain Inventory score; P < 0.05 versus zoledronic acid), and reduced the frequency of a shift from no/weak opioid analgesic use to strong opioids (P < 0.05 versus zoledronic acid at months 3-5). Denosumab delayed the time to moderate-to-severe pain compared with zoledronic acid in patients with mild or no pain at the baseline (P = 0.04), supporting early treatment. Health-related quality-of-life scores were similar in both groups. The number needed to treat to avoid one SRE for denosumab was 3 patient-years versus placebo and 10 patient-years versus zoledronic acid. CONCLUSION: The use of denosumab was associated with better prevention of the complications of metastatic bone disease secondary to solid tumors or multiple myeloma versus zoledronic acid.

A randomized trial of a single-dose rasburicase versus five-daily doses in patients at risk for tumor lysis syndrome.

BACKGROUND: Tumor lysis syndrome (TLS) is a life-threatening disorder characterized by hyperuricemia and metabolic derangements. The efficacy of rasburicase, administered daily for 5 days, has been well established. However, the optimal duration of therapy is unknown in adults. PATIENTS AND METHODS: We evaluated the efficacy of rasburicase (0.15 mg/kg) administered as single dose followed by as needed dosing (maximum five doses) versus daily dosing for 5 days in adult patients at risk for TLS. RESULTS: Eighty of the 82 patients enrolled received rasburicase; 40 high risk [median uric acid (UA) 8.5 mg/dl; range, 1.5-19.7] and 40 potential risk (UA = 5.6 mg/dl; range, 2.4-7.4). Seventy-nine patients (99%) experienced normalization in their UA within 4 h after the first dose; 84% to an undetectable level (<0.7 mg/dl). Thirty-nine of 40 (98%) patients in the daily-dose arm and 34 of 40 (85%) patients in single-dose arm showed sustained UA response. Six high-risk patients within the single-dose arm required second dose for UA >7.5 mg/dl. Rasburicase was well tolerated; one patient with glucose-6-phosphate dehydrogenase deficiency developed methemoglobinemia and hemolysis. CONCLUSIONS: Rasburicase is highly effective for prevention and management of hyperuricemia in adults at risk for TLS. Single-dose rasburicase was effective in most patients; only a subset of high-risk patients required a second dose.

Immunological variables as predictors of prognosis in patients with Kaposi's sarcoma and the acquired immunodeficiency syndrome.

Multivariate analysis was used to identify which of a large number of pretreatment immunological parameters correlated with therapeutic response, subsequent development of opportunistic infection, and survival from the time of diagnosis in a group of 70 patients with Kaposi's sarcoma and acquired immunodeficiency syndrome treated with recombinant leukocyte A interferon. In a logistic regression model, delayed type hypersensitivity response to one or more recall antigens and high proliferative response to Escherichia coli were significant predictors for response to recombinant leukocyte A interferon (for the model, P = 0.01). For prediction of the development of opportunistic infection, the model selected low proliferative responses to phytohemagglutinin and E. coli (P less than 0.001). Favorable factors predicting survival in the Cox regression model were the absence of endogenous serum interferon activity and a high proliferative response to E. coli (P less than 0.001). The estimated median survival for the group with endogenous serum interferon activity and low E. coli response was 12 months; the median has not yet been reached for the group with no serum interferon and a high E. coli response. We conclude that immunological parameters may be useful in predicting prognosis in patients with Kaposi's sarcoma and acquired immunodeficiency syndrome.

Evaluating results from the multiple myeloma patient subset treated with denosumab or zoledronic acid in a randomized phase 3 trial.

In a phase 3 trial of denosumab vs zoledronic acid in patients (n=1776) with bone metastases and solid tumors or multiple myeloma, denosumab was superior to zoledronic acid for the primary end point of prevention of skeletal-related events. There was no difference in overall survival between the two groups; however, an ad hoc overall survival analysis in the multiple myeloma subset of patients (n=180) favored zoledronic acid (hazard ratio (HR) 2.26; 95% confidence interval (CI) 1.13-4.50; P=0.014). In the present analysis, we found imbalances between the groups with respect to baseline risk characteristics. HRs with two-sided 95% CIs were estimated using the Cox model. After adjustment in a covariate analysis, the CI crossed unity (HR 1.86; 95% CI 0.90-3.84; P=0.0954). Furthermore, we found a higher rate of early withdrawals for the reasons of lost to follow-up and withdrawal of consent in the zoledronic acid group; after accounting for these, the HR was 1.31 (95% CI 0.80-2.15; P=0.278). In conclusion, the survival results in multiple myeloma patients in this trial were confounded and will eventually be resolved by an ongoing phase 3 trial.

Effect of denosumab versus zoledronic acid in preventing skeletal-related events in patients with bone metastases by baseline characteristics.

BACKGROUND: Analyses of phase III trials showed that denosumab was superior to zoledronic acid (ZA) in preventing skeletal-related events (SREs) irrespective of age, history of SREs, or baseline pain status. This analysis assessed the risk of SREs across additional baseline characteristics. PATIENTS AND METHODS: Patients (N = 5543) from three phase III trials who had breast cancer, prostate cancer, or other solid tumours and one or more bone metastasis were included. Superiority of denosumab versus ZA in reducing risk of first SRE and first and subsequent SREs was assessed in subgroups defined by the Eastern Cooperative Oncology Group performance status (ECOG PS), bone metastasis location, bone metastasis number, visceral metastasis presence/absence, and urinary N-telopeptide (uNTx) level using Cox proportional hazards and Anderson-Gill models. Subgroups except bone metastasis location were also assessed for each solid tumour type. RESULTS: Compared with ZA, denosumab significantly reduced the risk of first SRE across all subgroups (hazard ratio [HR] ranges: ECOG PS, 0.79-0.84; bone metastasis location, 0.78-0.83; bone metastasis number, 0.78-0.84; visceral metastasis presence/absence, 0.80-0.82; uNTx level, 0.73-0.86) and reduced the risk of first and subsequent SREs in all subgroups (HR ranges: ECOG PS, 0.76-0.83; bone metastasis location, 0.78-0.84; bone metastasis number, 0.79-0.81; visceral metastasis presence/absence, 0.79-0.81; uNTx level, 0.74-0.83). Similar results were observed in subgroups across tumour types. CONCLUSION: Denosumab was superior to ZA in preventing SREs in patients with bone metastases from advanced cancer, regardless of ECOG PS, bone metastasis number, baseline visceral metastasis presence/absence, and uNTx level.

Impact of therapy with epoetin alfa on clinical outcomes in patients with nonmyeloid malignancies during cancer chemotherapy in community oncology practice. Procrit Study Group.

PURPOSE: To study the impact of Procrit (epoetin alfa; Amgen Inc, Thousand Oaks, CA) on quality of life, transfusion requirements, and hemoglobin in anemic cancer patients receiving chemotherapy. PATIENTS AND METHODS: More than 500 community-based oncologists enrolled 2,342 patients with malignancies undergoing cytotoxic chemotherapy in an open-label study. Patients were treated with epoetin alfa 150 U/kg three times weekly, which could be doubled if the therapuetic response was judged inadequate. Total treatment was up to 4 months. RESULTS: Of the 2,342 patients enrolled, data were available for 2,030 patients. Of the 2,030, 1,047 patients completed all 4 months of epoetin alfa therapy. Epoetin alfa was associated with significant increases in mean self-rated scores for energy level, activity level, and overall quality of life; these improvements correlated with the magnitude of the hemoglobin increase and were independent of tumor response. In addition, epoetin alfa was associated with a significant increase in mean hemoglobin and with a significant decrease in the proportion of patients requiring transfusions (baseline to final value, P < .001). Epoetin alfa was well tolerated. CONCLUSION: Epoetin alfa is effective in improving the functional status and quality of life in anemic cancer patients receiving chemotherapy, as well as increasing hemoglobin level and decreasing transfusion requirements. Improvement in functional status can be attributed to an increase in hemoglobin level, demonstrating that quality of life in this group of patients can be improved by aggressively treating anemia. Further studies will be required to define the optimal doses and schedules for epoetin alfa.

Phase I trial of a mouse monoclonal antibody against GD3 ganglioside in patients with melanoma: induction of inflammatory responses at tumor sites.

Twenty-one patients were entered into a phase I trial to evaluate toxicity, antitumor effects, and biological responses at tumor sites during treatment of R24, an immunoglobulin G3 (IgG3) mouse monoclonal antibody (mAb) against GD3 ganglioside. Toxicity was related to dose of R24. Urticaria and pruritus were the most prominent side effects, with nausea, vomiting, and diarrhea occurring at the highest dose levels. Partial responses were observed in four patients lasting from 6 to 46 weeks, and mixed responses were seen in two patients. Responses occurred as early as 4 weeks and as late as 10 weeks after beginning treatment. Twenty of the 21 patients developed human IgG antibodies against R24. Antimouse Ig antibodies were first detected at a median of 14 days after starting treatment, but three of the four patients who had a partial response developed the antimouse Ig responses later than 20 days. Peak serum levels of R24 were related to dose and ranged from a mean of 0.9 micrograms/mL at the lowest dose level (1 mg/m2/d) to 44 micrograms/mL at the highest dose (50 mg/m2/d). The amount of R24 reaching tumor sites corresponded to the dose administered, and R24 could be detected in tumors as late as 30 days after finishing treatment. Inflammation at tumor sites was observed during treatment. Biopsies of tumors taken before, during, and after treatment revealed that R24 induced deposition of complement components, increased numbers of mast cells with mast cell degranulation, and infiltration of T lymphocytes. These results suggest that treatment with R24 can produce a localized inflammatory response at tumor sites that is capable of producing tumor regression.

Phase I trial of recombinant interferon gamma in cancer patients.

Interferon gamma (IFN-gamma) is a lymphokine with potent in vitro effects on cell growth and immune function. We have investigated the effects of rIFN-gamma (sp act approximately 2 X 10(7) U/mg, purity greater than 99%) in 16 evaluable patients with advanced malignancy in a phase 1 trial. Patients were treated with six-hour intravenous (IV) infusions daily, five days a week for 2 weeks. After a 2-week rest period, the IV treatment cycle was repeated. Responders were maintained on repeated IV treatment cycles or daily intramuscular (IM) injections. Patients were entered at fixed dose levels of 0.1, 0.5, or 1.0 mg/m2/d. The maximum safely tolerated dose was 0.5 mg/m2. The most common side effects were constitutional symptoms, including fever, chills, fatigue, and myalgias. Reversible and transient increases in hepatic transaminase and decrease in granulocyte counts were seen. Treatment was associated with a dose-dependent increase in serum levels of beta 2 microglobulin. Partial responses (PRs) were observed in one patient with Hodgkin's disease and one patient with chronic lymphocytic leukemia. Fairly constant levels of serum IFN were found at four and six hours during infusion, followed by a rapid decline within one to two hours. We conclude that rIFN-gamma can be safely administered by a six-hour IV infusion and that it can induce in vivo some of the biologic effects reported in in vitro studies.

Abrogating chemotherapy-induced myelosuppression by recombinant granulocyte-macrophage colony-stimulating factor in patients with sarcoma: protection at the progenitor cell level.

PURPOSE: The purpose of this study was to optimize the dose, schedule, and timing of recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) administration that would best abrogate myelosuppression in patients with sarcoma. PATIENTS AND METHODS: Sarcoma patients who had experienced severe myelosuppression after chemotherapy with Cytoxan (cyclophosphamide; Bristol-Myers Squibb Co, Evansville, IN), Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), and dacarbazine ([CyADIC], cycle 1) were eligible. GM-CSF was administered during a 14-day period until 1 week before cycle 2 of CyADIC and was resumed 2 days after cycle 2 completion. The schedule subsequently was modified to allow the earlier administration of GM-CSF in which CyADIC was compressed from 5 days to 3 days, and GM-CSF was administered immediately after the discontinuation of CyADIC in cycle 2. To understand better the impact of GM-CSF on bone marrow stem cells, the proliferative status of bone marrow progenitors was examined during treatment. To evaluate the effects of GM-CSF on effector cells, select functions of mature myeloid cells were also examined. RESULTS: In the seven patients who were treated on the initial schedule, GM-CSF enhanced the rate of neutrophil recovery; however, severe neutropenia was not abrogated, By using the modified schedule in 17 patients, GM-CSF significantly reduced both the degree and the duration of neutropenia and myeloid (neutrophils, eosinophils, and monocytes) leukopenia. The mean neutrophil and mature myeloid nadir counts were 100/mm3 and 280/mm3 in cycle 1 and 290/mm3 and 1,540/mm3 in cycle 2 (P less than .01 and P less than .001). The duration of severe neutropenia (neutrophil count less than 500/mm3) and myeloid leukopenia (myeloid leukocyte count less than 1,000/mm3) were reduced from 6.2 and 6.8 days in cycle 1 to 2.8 and 1.4 days in cycle 2 (P less than .001). While 16 of 17 patients experienced severe myeloid leukopenia (less than 500/mm3) in cycle 1, only two of 17 experienced severe myeloid leukopenia in cycle 2 (P less than .001). Overall, severe neutropenia was abrogated in seven patients, which made them eligible for dose-escalation of Adriamycin. The fraction of cycling progenitors increased threefold on GM-CSF and decreased dramatically below the baseline within 1 day of GM-CSF discontinuation. CONCLUSIONS: The modified schedule improved the beneficial effects of GM-CSF by enhancing myeloprotection and permitting dose-intensification of chemotherapy. The increased myeloid mass and quiescent progenitors at the initiation of chemotherapy suggest that GM-CSF might allow further chemotherapy dose-rate intensification by shortening the interval between courses.

High-dose ifosfamide in bone and soft tissue sarcomas: results of phase II and pilot studies--dose-response and schedule dependence.

PURPOSE: To evaluate the efficacy and feasibility of high-dose ifosfamide (HDI) at a total dose of 14 g/m2 per cycle with mesna in combination with granulocyte colony-stimulating factor (G-CSF) in adult patients with sarcomas. PATIENTS AND METHODS: Between July 1991 and February 1994, 74 patients with sarcomas (37 bone and 37 soft tissue) were treated on two simultaneous phase II studies that evaluated HDI given as a continuous infusion over 74 hours. G-CSF was started on day 5 at 5 microg/kg/d until recovery of granulocyte count. Additionally, between March 1993 and March 1994, 15 similar patients with previously treated bone or soft tissue sarcomas were treated on a pilot study in which the same total dose of ifosfamide was administered by a bolus schedule, along with mesna and G-CSF. Patients were treated until maximal response, and where possible, surgical resection of gross disease was performed. RESULTS: Seventy-two patients from the phase II study using continuous infusion are assessable for response. Four complete responses (CRs) and 17 partial responses (PRs) were noted, for an overall response rate of 29% (95% confidence interval [CI], 19% to 39%). The response rate was 40% (95% CI, 24% to 56%) for bone sarcomas and 19% (95% CI, 6% to 32%) for soft tissue sarcomas. Fourteen patients from the pilot study that used a bolus schedule are assessable for response. One CR and seven PRs were noted, for an overall response rate of 57% (95% CI, 31% to 83%) and a response rate of 45% for soft tissue sarcomas. Two patients developed grade 3 to 4 renal toxicity, three developed grade 3 CNS toxicity, one had possible grade 3 cardiac toxicity, and two developed severe painful peripheral neuropathy. There were no treatment-related deaths. CONCLUSION: HDI at 14 g/m2 with mesna and G-CSF is an active salvage regimen for patients with bone and soft tissue sarcomas. There is a definite positive dose-response curve, and bolus administration appears to be more active than continuous infusion.

Effects of interleukin-1 alpha on carboplatin-induced thrombocytopenia in patients with recurrent ovarian cancer.

PURPOSE: The purpose of this study was to evaluate the clinical safety and ability of interleukin-1 alpha (IL-1 alpha) to ameliorate carboplatin-induced thrombocytopenia and thus allow patients with ovarian cancer to receive multiple cycles of chemotherapy at full doses. PATIENTS AND METHODS: IL-1 alpha was administered by continuous intravenous infusion daily at doses of 0.1 to 10 micrograms/m2/24 hours over 4 days (96 hours) before the first cycle and/or following the second cycle of carboplatin in 21 patients with recurrent ovarian cancer who had platinum-responsive disease. In cycle no. 1, patients received carboplatin (400 mg/m2) alone, while in cycle no. 2 carboplatin was followed by IL-1 alpha. RESULTS: Treatment with IL-1 alpha before carboplatin was associated with moderate leukocytosis (baseline mean, 6.15 x 10(3)/microL; maximum mean, 17.9 x 10(3)/microL; P < .001) and significant increases in platelet counts (baseline mean, 241 x 10(3)/microL; maximal mean, 392 x 10(3)/microL; P < .001). IL-1 alpha following carboplatin significantly reduced the duration of thrombocytopenia (days platelet count < 50,000, 5.1 to 2.9 days; P = .003) and increased the area under the curve (AUC) of platelets as a function of time (P < .001). The mean nadir platelet counts were 54,000/microL and 67,000/microL (P = .08) in cycles no. 1 and 2, respectively. In fact, seven of 12 patients given 3 micrograms/m2/d of IL-1 alpha had less thrombocytopenia in cycle no. 2 than in cycle no. 1. Treatment with IL-1 alpha was associated with the tolerance of multiple cycles of carboplatin at the same dose in several patients. The maximum-tolerated dose (MTD) was 3 micrograms/m2/d; fever, chills, hypotension, and fluid retention were dose-limiting toxic effects. CONCLUSION: These findings demonstrate that IL-1 alpha can enhance recovery of platelets following carboplatin therapy and suggest a potential therapeutic role for IL-1 alpha in attenuating thrombocytopenia associated with chemotherapy.

Effects of PIXY321, a granulocyte-macrophage colony-stimulating factor/interleukin-3 fusion protein, on chemotherapy-induced multilineage myelosuppression in patients with sarcoma.

PURPOSE: To evaluate the clinical safety and ability of PIXY321, a novel fusion protein of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), to ameliorate chemotherapy-induced multilineage myelosuppression. PATIENTS AND METHODS: PIXY321 was administered by subcutaneous injection twice daily (25 to 1,000 micrograms/m2/d) over 14 days to 24 chemotherapy-naive patients with sarcoma in a phase I/II study. Three weeks from the initiation of PIXY321, the first cycle of chemotherapy with cyclophosphamide, doxorubicin, and dacarbazine (DTIC) (CyADIC) was administered over 3 days. Four weeks later, a second cycle of CyADIC was administered, followed by 14 days of PIXY321. RESULTS: Treatment with PIXY321 was well tolerated. Local skin reactions and constitutional symptoms were the main side effects. The dose-limiting toxicity was not encountered; however, headache and fatigue were more frequent at the highest dose (1,000 micrograms/m2). PIXY321 before chemotherapy elicited a modest increase in the WBC count (consisting mainly of mature neutrophils), platelets, and corrected reticulocyte counts (all P < .001). Following chemotherapy, PIXY321 at effective doses (500 to 1,000 micrograms/m2/d), significantly reduced both the degree (mean nadir, 70 v 310/microL; P = .016) and duration (mean days < 500/microL, 6.6 v 3.9 days; P = .002) of neutropenia. Cumulative thrombocytopenia was not observed during the first two cycles of CyADIC (mean nadir platelet count, 103 v 95 x 10(3)/microL, in cycles no. 1 and 2, respectively; P = NS). Compared with our historic control data, the mean nadir platelet count in cycle no. 2 was significantly higher after PIXY321 (1.7-fold, P < .05) than with CyADIC alone or with GM-CSF support. There was a suggestion for a dose response, since the mean percentage change in nadir platelet values from cycle no. 1 to cycle no. 2 increased with the PIXY321 dose (P < .02), with the peak effect observed at 750 micrograms/m2/d. CONCLUSION: These results suggest a potential clinical role for PIXY321 in attenuating the cumulative multilineage hematopoietic toxicity of chemotherapy.

Bcl-1 gene rearrangements in B cell lymphoma.

We analyzed 50 B cell lymphoma samples by Southern blot analysis, using the bcl-1 and heavy chain immunoglobulin (JH) probes with two or more restriction endonucleases. All samples showed JH rearrangement, and three samples (two diffuse small lymphocytic lymphomas and one diffuse large cell lymphoma probably transformed from a diffuse small lymphocytic lymphoma) demonstrated rearranged bcl-1 sequences. The three samples showed the t(11;14)(q13;q32) chromosome translocation, and all three contained rearranged JH fragments that comigrated with the rearranged bcl-1 fragment. The breakpoint of the translocation occurred within a 1.6-kb region on chromosome 11 in the three cases. Two of the three patients had primary refractory disease. Two of the three patients had gastrointestinal involvement. Bcl-1 rearrangement may identify an unusual subset of patients with primary refractory disease with gastrointestinal involvement. It may also describe a unique subset of large cell lymphoma patients transformed from diffuse small cell histology.

The in vivo effects of PIXY321 therapy on human monocyte activity.

In this report we describe the time-dependent effects of PIXY321 (a synthetic hybrid cytokine) treatment (500 and 750 micrograms/m2/day for 14 days) on six sarcoma patients. Blood was taken prior to PIXY321 injection (day 0), on days 1, 7, and 14 of treatment, and 7 days posttreatment (day 21). The number of isolated monocytes quadrupuled by day 7 and sustained a significant increase through day 14. There were significant increases in the percentage of circulating monocytes relative to total mononuclear cells on days 1 and 7 of therapy. There were no significant changes in monocyte cell surface antigens (15 checked), suggesting that the increase in monocyte numbers was not due to increased numbers of immature monocytes. The basal activity of the monocytes was not markedly altered during treatment; however, they were primed for significantly increased phorbol 12,13-dibutyrate-stimulated superoxide anion production and endotoxin-stimulated release of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) on days of 1 and 7 of therapy. There was a significant increase of IL-1 beta mRNA levels (unstimulated cells) on days 1 and 7, but TNF-alpha mRNA levels increased significantly on day 1 only. Consistent with the increase in superoxide anion production, there were increases in monocyte protein kinase C (PKC) levels on all days of therapy. There was a significant increase in PKCII beta mRNA only on the first day of treatment. All significant changes in monocyte number and function produced by PIXY321 infusion were reversible, as there were no sustained effects on day 21 (7 days after therapy). These results indicate that the effects of PIXY321 may be mediated through up-regulation of PKC resulting in monocytes primed for increased functional activity in response to an appropriate second stimulus.

The in vivo effects of rhIL-1 alpha therapy on human monocyte activity.

Pleiotropic cytokines such as interleukin-1 alpha (IL-1 alpha) have multiple effects on peripheral blood monocytes (PBMs). This study examined the ability of in vivo recombinant human IL-1 alpha (rhIL-1 alpha) therapy to enhance clinically important monocyte functions in ovarian cancer patients prior to chemotherapy. After 4 days of continuous infusion, in vivo rhIL-1 alpha therapy amplified both the number and activity of PBMs. Therapy with rhIL-1 alpha increased the number of PBMs sixfold. These monocytes had a significantly increased ability to produce superoxide anion in response to phorbol 12,13-dibutyrate stimulation. Their ability to secrete spontaneously the immunomodulatory cytokines IL-1 alpha and IL-1 beta was significantly increased, but their ability to secrete tumor necrosis factor alpha (TNF-alpha) was not significantly elevated. These effects of rhIL-1 alpha infusion on cytokine secretion by PBMs appear to be related to rhIL-1 alpha-induced increases in the mRNA levels for these cytokines. In contrast, rhIL-1 alpha therapy did not significantly alter PBM response to lipopolysaccharide (10 micrograms/ml). In summary, infused rhIL-1 alpha, in addition to its use as a myeloprotective agent, has enhancing effects on the number and activity of PBMs. The effects of rhIL-1 alpha infusion on PBM function demonstrated here should at least transiently increase the ability of monocytes to combat infection and enhance host immune response.

Cell cycle status of erythroid (BFU-E) progenitor cells from the bone marrows of patients on a clinical trial with purified recombinant human granulocyte-macrophage colony-stimulating factor.

Human Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) is active in vitro as a Burst Promoting Activity (BPA) for human erythroid (BFU-E) progenitor cells. In order to evaluate the effectiveness of GM-CSF as a proliferation-inducing stimulus for BFU-E in vivo, bone marrow cells from patients on a phase I/II clinical trial with recombinant human (rh) GM-CSF, were assessed in vitro for effects on the cycling status of BFU-E. Prior to treatment, BFU-E from marrows of the majority of these patients were in a slowly cycling state. Administration of rhGM-CSF to the patients enhanced BFU-E proliferation, and cessation of treatment with rhGM-CSF resulted in BFU-E returning to a slowly cycling state. Similar results were noted for CFU-GM. This study demonstrates that rhGM-CSF has proliferation-inducing activity for BFU-E in vivo, substantiating the in vitro BPA activity previously noted for GM-CSF, although it is not possible from the present studies in vivo to determine if this effect on BFU-E is directly or indirectly mediated.

Growth characteristics of marrow hematopoietic progenitor/precursor cells from patients on a phase I clinical trial with purified recombinant human granulocyte-macrophage colony-stimulating factor.

Bone marrow cells from patients with leukemia, myelodysplastic syndromes, cancer, and other disorders on a phase I clinical trial with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) were assessed in vitro for numbers of granulocyte-macrophage (CFU-GM), erythroid (BFU-E), and multipotential (CFU-GEMM) progenitor cells, and for growth patterns (colony-to-cluster ratio) of CFU-GM, cycling rates of CFU-GM, and responsiveness in vitro to colony-stimulating and colony-inhibiting factors. The colony-to-cluster ratio of CFU-GM and the dose-response curves of CFU-GM to stimulation by rhGM-CSF in vitro did not change during the clinical trial. However, the percentage of CFU-GM in DNA synthesis, which is a measure of the proliferative rates of these cells, determined by the high specific activity tritiated thymidine kill technique in vitro, was markedly enhanced in a reversible fashion after administration in vivo of rhGM-CSF. The increased cycling rates of CFU-GM were consistent with the induced increase in neutrophil counts in these patients that has been reported elsewhere. Additionally, marrow CFU-GM from patients given rhGM-CSF in vivo were increased in sensitivity to inhibition in vitro by recombinant human H-subunit (acidic) ferritin in two of eight cases, and were increased in sensitivity to inhibition by lower dosages of recombinant human tumor necrosis factor alpha in all patients evaluated. The sensitivity of CFU-GM to inhibition in vitro by recombinant human interferon gamma and prostaglandin E1 did not change during the clinical trial. These studies demonstrate that the rhGM-CSF is having an effect on CFU-GM in the patients on the phase I clinical trial. This information may be of significance in planning future clinical studies combining rhGM-CSF with chemotherapy and/or other biotherapy.

Kinetic response of human marrow myeloid progenitor cells to in vivo treatment of patients with granulocyte colony-stimulating factor is different from the response to treatment with granulocyte-macrophage colony-stimulating factor.

We previously demonstrated that granulocyte-macrophage colony-stimulating factor (GM-CSF) induced sustained increases in cycling of myeloid progenitors in patients with sarcoma. However, decreased proliferation of these cells to a slow- or noncycling state, below pretreatment levels, occurred within 1 to 2 days and maintained for at least 1 week after discontinuation of GM-CSF. To assess possible biological differences in GM-CSF and granulocyte (G)-CSF in such kinetic effects, we evaluated cycling status of marrow progenitors before, during, and after administration of recombinant human G-CSF (5 micrograms/kg/d subcutaneously [s.c.]) to six patients with sarcoma for 8 days. On the last (8th) day of G-CSF treatment, cycling rates of colony-forming units-granulocyte/macrophage (CFU-GM), burst-forming units-erythroid (BFU-E), and multipotent colony-forming units (CFU-GEMM) were enhanced 1.5- to 1.9-fold, to values of 40 +/- 10% to 58 +/- 5%. In sharp contrast to patients receiving GM-CSF, however, progenitor cells from patients off G-CSF treatment for 2 to 4 days were still rapidly proliferating. These differences in proliferative kinetics may be of use for design of clinical trials to efficaciously utilize these growth factors.

Effects of in vivo treatment with PIXY321 (GM-CSF/IL-3 fusion protein) on proliferation kinetics of bone marrow and blood myeloid progenitor cells in patients with sarcoma.

PIXY321, a stimulator of multipotent colony-forming units (CFU-GEMM), burst-forming unit-erythroid (BFU-E), and colony-forming units granulocyte/macrophage (CFU-GM) progenitor cell proliferation in vitro, is currently being assessed in phase-I/-II clinical trials. We evaluated kinetics of CFU-GEMM, BFU-E, and CFU-GM proliferation in bone marrow (BM), blood, and granulocyte (CFU-G) and macrophage (CFU-M) progenitors in BM of chemotherapy-naive patients with sarcoma-administered PIXY321 (25 to 1000 micrograms/m2/day subcutaneously for 14 days). BM and/or blood cells from three to four patients at each dosage were assessed before, during, 1 to 2 days, and 7 days following treatment with PIXY321. Cells were pulse-treated in vitro with or without high-specific activity tritiated thymidine (3H-dThr) (to assess the percentage of progenitors in S-phase of cell cycle) and cultured for immature and more mature subsets of CFU-GEMM, BFU-E, CFU-GM, and for CFU-G and CFU-M. Despite heterogeneity in baseline cycling status of progenitors in BM, administration of 125 to 500 micrograms PIXY321 to patients at least doubled (p < 0.001) cycling rates of all BM progenitors. The cycling rates of blood progenitors increased from a slow or non-cycling state to > 38% cells in cycle. Within 1 to 2 days after cessation of PIXY321 infusion, all progenitors were in a slow or noncycling phase below that of many of the pre-BM samples (immature and mature CFU-GM and mature BFU-E) or were back to background levels (CFU-G, CFU-M, CFU-GEMM, and immature BFU-E). These cycling effects were similar to those previously noted for BM CFU-GM and BFU-E in patients on clinical trial with GM-CSF. In contrast, higher dosages of PIXY321, especially 1000 micrograms, increased cycling of BM and blood progenitor cells early during treatment, but cycling rates decreased while patients were still being administered PIXY321; decreased cycling was maintained after cessation of PIXY321. PIXY321 is thus highly active in vivo as a stimulator of multipotential and more lineage-restricted progenitors. The kinetics of progenitor cell proliferation noted in this study highlight differences seen with GM-CSF and G-CSF. The effects described here could be of relevance in design of future clinical trials using PIXY321 as an adjunct treatment in patients undergoing cytoreductive therapy.

The effects of treatment with PIXY321 (GM-CSF/IL-3 fusion protein) on human polymorphonuclear leukocyte function.

During a phase I trial of the genetically engineered hematopoietic growth factor PIXY321 (granulocyte-macrophage colony-stimulating factor/interleukin-3 [IL-3] fusion protein), we examined the effects of PIXY321 treatment on human polymorphonuclear leukocyte (PMN) locomotive, respiratory burst, and phagocytic responses. PIXY321 treatment was associated with transient suppression of both unstimulated locomotion and chemotaxis responses to multiple stimuli, as well as significant transient enhancement of formyl peptide-stimulated H2O2 production. No effects on opsonic phagocytosis of Staphylococcus aureus were observed. In vitro exposure of control PMN to PIXY321 resulted in suppression of unstimulated locomotion/chemotaxis and enhancement of formyl peptide-stimulated H2O2 production but had no effects on phagocytosis. When patient cells were exposed in vitro to PIXY321 during treatment, suppression of chemotaxis and enhancement of H2O2 production were observed before PIXY321 treatment, but these effects diminished during treatment. The in vivo and in vitro exposure effects of PIXY321 treatment on PMN function are similar to those of the parent molecule, granulocyte-macrophage colony-stimulating factor (GM-CSF).