A Phase I/IIa Study of Antidisialoganglioside Antibody Dinutuximab in Japanese Patients With Neuroblastoma.

Japanese patients with neuroblastoma completing induction therapy and high-dose chemotherapy received antidisialoganglioside antibody dinutuximab 17.5 mg/m2 for 4 days during each of 5 consecutive 28-day cycles. Patients also received macrophage colony-stimulating factor (M-CSF) or granulocyte colony-stimulating factor (G-CSF) during cycles 1, 3, and 5 combined with interleukin-2 teceleukin during cycles 2 and 4. A total of 25 patients (11 in the M-CSF group and 14 in the G-CSF group) were enrolled, and dose-limiting toxicity was assessed in the first 12 patients (6 in each group). The recommended doses of dinutuximab, M-CSF, and G-CSF were determined to be 17.5 mg/m2, 6.0×106 U/m2, and 5 µg/kg/d, respectively, whereas that of teceleukin was 0.75×106 IU/m2 during week 1 and 1×106 IU/m2 during week 2. The most common grade 3 or 4 adverse events in both groups were neutrophil count decreased, platelet count decreased, pyrexia, and alanine aminotransferase increased. Four patients (2 in each group) discontinued the treatment because of adverse events. At the end of the study, survival was confirmed in 22 patients (9 in the M-CSF group and 13 in the G-CSF group). From these results, we concluded that this combination regimen is a feasible treatment for Japanese patients with neuroblastoma.

Characterisation of a novel Fc conjugate of macrophage colony-stimulating factor.

We have produced an Fc conjugate of colony-stimulating factor (CSF) 1 with an improved circulating half-life. CSF1-Fc retained its macrophage growth-promoting activity, and did not induce proinflammatory cytokines in vitro. Treatment with CSF1-Fc did not produce adverse effects in mice or pigs. The impact of CSF1-Fc was examined using the Csf1r-enhanced green fluorescent protein (EGFP) reporter gene in MacGreen mice. Administration of CSF1-Fc to mice drove extensive infiltration of all tissues by Csf1r-EGFP positive macrophages. The main consequence was hepatosplenomegaly, associated with proliferation of hepatocytes. Expression profiles of the liver indicated that infiltrating macrophages produced candidate mediators of hepatocyte proliferation including urokinase, tumor necrosis factor, and interleukin 6. CSF1-Fc also promoted osteoclastogenesis and produced pleiotropic effects on other organ systems, notably the testis, where CSF1-dependent macrophages have been implicated in homeostasis. However, it did not affect other putative CSF1 targets, notably intestine, where Paneth cell numbers and villus architecture were unchanged. CSF1 has therapeutic potential in regenerative medicine in multiple organs. We suggest that the CSF1-Fc conjugate retains this potential, and may permit daily delivery by injection rather than continuous infusion required for the core molecule.

Clinical usefulness of macrophage colony-stimulating factor for ovarian cancers: Long-term prognosis after five years.

We performed a randomized double blind study between 1992 and 1995 in which 214 patients with FIGO stage I to III ovarian cancers received administration of 10(6) units (low dose group) or 8x10(6) units (high dose group) of macrophage colony-stimulating factor (M-CSF) after cyclophosphamide/adriamycin/cisplatin (CAP) therapy. The period required to finish a set of intensive chemotherapy, which was the primary endpoint, was significantly shortened (p=0.0004), and the incidence of febrile neutropenia significantly decreased (p=0.04). In this study, we followed the patients for a prolonged period. The patients were divided into two groups: patients with complete tumor excision and those with incomplete excision, then the relapse rate and survival rate 5 years after initiation of the clinical study were compared. The relapse rate tended to be lower in the high dose group than in the low dose group in patients with no residual tumor (p=0.0750). However, there was no difference in the relapse rate between the two dose groups in patients with residual tumor. Although there were no significant differences in the survival rate between the high and low dose groups in patients with or without residual tumor, the survival rate in mucinous adenocarcinoma patients with no residual tumor was 64.3% in the low dose group (n=14) and 92.3% in the high dose group (n=14), showing a significantly higher rate (p=0.0436), and the survival rate tended to be higher in the high dose group in patients with serous adenocarcinoma (p=0.0786). Furthermore, in patients aged 40 years or younger with no residual tumor, the survival rates were 73.9 and 100% in the low and high dose groups, respectively, showing a significantly higher rate in the high dose group (p=0.0310). Our results suggest that administration of M-CSF can improve the long-term prognosis of ovarian cancer patients with no residual tumor, but further prospective randomized trials with a primary endpoint of relapse-preventing effect are needed.

Therapeutic use of cytokines to modulate phagocyte function for the treatment of infectious diseases: current status of granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, macrophage colony-stimulating factor, and interferon-gamma.

The innate immune system represents the initial arm of host defense against pathogenic bacteria, fungi, and parasites. Neutrophils, monocytes, and tissue-based macrophages are major cellular components of this system. The potential ability to augment activity of the innate immune system has increased dramatically during the past 2 decades, with the discovery and development of cytokines. Four cytokines, namely granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), and interferon (IFN)-gamma, have received increasing attention as potential adjunctive agents for the treatment of infectious diseases. In various animal models of infection, therapeutic administration of each of the 4 cytokines has been shown to enhance pathogen eradication and to decrease morbidity and/or mortality. However, variable therapeutic efficacy has been reported in clinical trials conducted to date. This review summarizes the current status of the use of G-CSF, GM-CSF, M-CSF, and IFN-gamma in the treatment of infectious diseases.

Human urinary macrophage colony-stimulating factor reduces the incidence and duration of febrile neutropenia and shortens the period required to finish three courses of intensive consolidation therapy in acute myeloid leukemia: a double-blind controlled study.

PURPOSE: To determine whether macrophage colony-stimulating factor (M-CSF) reduces the incidence and duration of febrile neutropenia during three courses of intensive consolidation therapy and whether it shortens time to complete consolidation therapy. PATIENTS AND METHODS: In 198 adult patients with acute myeloid leukemia (AML) in complete remission (CR), M-CSF (8 x 10(6) U/d) or placebo was administered from 1 day after the end of each consolidation chemotherapy for 14 days. RESULTS: The duration and incidence of febrile neutropenia was significantly reduced by 34% (P = .00285) and 17% (P = .02065), respectively, in 88 assessable patients in the M-CSF group compared with those in 94 assessable patients in the placebo group. Patients in the M-CSF group had 565 days and 133 episodes of febrile neutropenia during 7,901 days at risk, while patients in the placebo group had 977 days and 185 episodes during 9,077 days at risk. The median period required to finish the three courses of consolidation therapy was 93 days in the M-CSF group, which was significantly shorter than 110 days in placebo group (P = .0050). In the M-CSF group, the recovery of neutrophils and platelets was significantly faster (P = .0348 and P = 0.0364, respectively), the administration of systemic antimicrobial agents tended to be less (P = .0839), and the frequency of platelet transfusion (P = .0259) and the total volume of transfused platelets (P = .0292) were significantly less. However, there was no significant difference in the disease-free survival. CONCLUSION: M-CSF significantly reduced the incidence and duration of febrile neutropenia during the intensive consolidation therapy, and shortened the time to complete consolidation chemotherapy in AML.

Development of nephrotic syndrome in a patient with acute myeloblastic leukemia after treatment with macrophage-colony-stimulating factor.

We describe a patient with acute myeloblastic leukemia (AML) who developed nephrotic syndrome after receiving several courses of chemotherapy, including macrophage-colony-stimulating factor (M-CSF). At the onset of nephrotic syndrome, the patient remained in a hematological remission. A renal biopsy showed diffuse mesangial proliferation with marked glomerular infiltration of macrophages and massive subendothelial and mesangial deposits. After the institution of the combined therapy with corticosteroid, anticoagulant, and dipyridamole, urinary protein excretion was attenuated to less than 1.0 g/day. It should be emphasized that the recurrence of nephrotic syndrome was observed after the following chemotherapy, including M-CSF, whereas the bone marrow still remained completely remitted. In contrast, after the last course of chemotherapy, which did not include M-CSF, urinary protein excretion was not enhanced. Of note is that the renal histology at autopsy showed a remarkable improvement of mesangial hypercellularity with concomitant reduction in the number of glomerular macrophages. These evolutional changes in both proteinuria and glomerular histology suggest a close linkage between the M-CSF treatment and macrophage-related glomerular injury. The possibility can be raised that M-CSF accelerated the underlying renal disease in this case through enhancing macrophage accumulation into the glomerulus, leading to the development of nephrotic syndrome.

Phase I study of continuous-infusion recombinant macrophage colony-stimulating factor in patients with metastatic melanoma.

Macrophage colony-stimulating factor (M-CSF) is a lineage-specific, homodimeric growth factor that supports the proliferation and maturation of bone marrow progenitors and the survival and function of mononuclear/macrophage cells. In vitro studies have demonstrated antitumor activity of macrophage colony-stimulating factor-treated monocytes against melanoma target cells. A Phase I study was conducted by administering the glycosylated form of the protein to patients with metastatic melanoma as two 7-day continuous i.v. infusions separated by a 2-week rest. Cohorts of three patients per dose level received escalating doses of 10-160 microgram/kg/day. Safety, clinical, and biological effects were evaluated. The infusions were well tolerated with occasional maximum grade 2 nonhematological toxicity. Rapidly reversible thrombocytopenia was the major hematological adverse effect. Its etiology may in part be explained by proliferation and activation of monocyte/macrophage cells in bone marrow samples. Evidence for a biological effect on tumors was suggested by the delayed, complete disappearance of multiple lesions in one patient and a decrease in the size of one marker lesion in a second patient with a mixed response. Fasting serum cholesterol levels decreased during the infusions and may represent an additional therapeutic application for this growth factor.

Ex vivo effects of macrophage colony-stimulating factor on human monocyte activity against fungal and bacterial pathogens.

The ex vivo effects of macrophage colony-stimulating factor (M-CSF) on antifungal and antibacterial activities of human elutriated monocytes were studied. Cells were isolated prior to the initiation of therapy, on day 3 and at week 7, in six patients with an advanced malignancy receiving M-CSF in a phase I study. Superoxide anion production by monocytes in response to N-formyl methionyl leucyl phenylalanine was enhanced at day 3 of therapy (P = 0.011). In addition, at day 3, fungicidal activity against blastoconidia of Candida albicans was enhanced by M-CSF treatment (P = 0.026), whereas antifungal activity against hyphae of Aspergillus fumigatus was not significantly changed. Bactericidal activity against Staphylococcus aureus was increased at day 3 (P = 0.004). By Northern blot analysis, M-CSF does not upregulate the expression of components of the NADPH-oxidase, the multicomponent enzyme system responsible for generation of superoxide radicals by monocytes. Instead, the predominant effect of M-CSF on circulating monocytes is probably a post-transcriptional effect. In conclusion, these findings suggest that administration of M-CSF to patients may enhance microbicidal activities and thus may provide a useful adjunct to conventional antimicrobial therapy.

Clinical toxicity of cytokines used as haemopoietic growth factors.

A number of cytokines are used as haemopoietic growth factors and this review focuses on toxicities associated with granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-1, IL-3, IL-4, IL-6 and macrophage colony-stimulating factor (M-CSF). Both GM-CSF and G-CSF, currently approved for clinical use, are generally well tolerated by the majority of patients during short term administration. Constitutional symptoms and bone pain are the most frequently reported adverse effects, but they are rarely treatment-limiting. Reactivation of rheumatoid symptoms, and exacerbation of autoimmune thyroiditis or autoimmune haematological disorders have sometimes been described. Severe cardiovascular complications include the possibility for arterial thromboses and the vascular leak syndrome, which is more specifically observed with GM-CSF. Reports of several cases and small series of patients have suggested that growth factors might increase the pulmonary toxicity of chemotherapy, a possibility that remains debated and requires further attention. Generalised or local cutaneous reactions are frequently noted with GM-CSF. Leukocytoclastic vasculitis was observed with both growth factors, while neutrophilic dermatoses have been mostly described with G-CSF. Exacerbation of psoriasis and isolated anaphylactic reactions have appeared with GM-CSF and G-CSF. The hepatotoxic potential of the growth factors is not clearly established, but the occurrence of coagulation abnormalities has recently been reported. Renal and biological disturbances are usually transient. Long term treatment with GM-CSF and G-CSF also seems to be well tolerated, but the possible occurrence of several adverse events, i.e. bone disorders, leukaemia, unmasking or acceleration of underlying disease, require further investigation in patients receiving prolonged treatment, as in myelodysplasia. Finally, antibodies against growth factors have been reported only with GM-CSF. Other cytokines are still under investigation. Flu-like and constitutional symptoms, sometimes dose-limiting, have been reported with IL-1, IL-3, IL-4 and IL-6, while M-CSF was occasionally associated with such adverse effects. More specific adverse events, also frequently considered as dose-limiting toxicities, include hypotension with IL-1, severe headache or skin rash with IL-3, and nasal congestion and gastroduodenal lesions with IL-4. Severe capillary leak syndrome has been reported only with IL-4. M-CSF toxicity is minimal and limited to reversible but sometimes dose-limiting thrombocytopenia and ophthalmological symptoms with the recombinant product. Again, the safety of long term administration of these cytokines has not yet been determined, and IL-3-induced disease progression in myelodysplastic patients has been suggested.

Phase II trial of murine monoclonal antibody D612 combined with recombinant human monocyte colony-stimulating factor (rhM-CSF) in patients with metastatic gastrointestinal cancer.

In a Phase II study, 14 patients with metastatic gastrointestinal cancer received the mAb D612 (40 mg/m2, days 4, 7, and 11) in combination with recombinant human monocyte colony-stimulating factor [(rhM-CSF) 80 micrograms/kg/days 1-14]. The combined treatment was well tolerated and resulted in characteristic biological activity associated with each of the agents. Thus, 10 of 14 patients experienced D612-associated secretory diarrhea, which responded to the prostaglandin inhibitor Indomethacin in 5 of 7 patients. rhM-CSF therapy was associated with peripheral monocytosis (peak absolute monocyte count, 1444 +/- 394/mm3) and thrombocytopenia (nadir count, 78 +/- 10/mm3). Monocyte surface marker analysis revealed a high baseline expression of CD16+ cells in our patient population with an additional increase with rhM-CSF therapy. We observed a correlation between the degree of thrombocytopenia and the pretreatment CD16+ monocyte count. Of the plasma cytokines assayed, serum Neopterin demonstrated the most consistent increase during rhM-CSF therapy. There was a significant difference in the half-life of the first and last dose of D612 (35.8 +/- 2 versus 27 +/- 2.9 h; P < 0.05). Eleven of fourteen patients developed low-moderate levels of anti-D612 antibody. Despite the observed biological activity of both rhM-CSF and D612 and the previously described in vitro synergy, no clinical antitumor responses were observed in this Phase II study.

A phase I study of anti-GD3 ganglioside monoclonal antibody R24 and recombinant human macrophage-colony stimulating factor in patients with metastatic melanoma.

BACKGROUND: Macrophages activated by macrophage-colony stimulating factor (M-CSF) are potent immune effector cells and can mediate both in vitro cytotoxicity and antitumor effects in vivo. A Phase I trial combining M-CSF with R24, a mouse monoclonal antibody against GD3 ganglioside that has been shown to localize to melanoma tumors, induce inflammation at tumor sites, and result in major tumor responses in some patients with melanoma was performed. METHODS: Nineteen patients with metastatic melanoma received a 14-day continuous intravenous infusion of 80 micrograms/kg/day of recombinant human M-CSF. R24 was administered daily by intravenous infusion on days 6-10 at doses of 1, 3, 10, 30, and 50 micrograms/m2/day. RESULTS: All patients developed pruritus and urticaria; 13 patients developed transient thrombocytopenia less than 100,000/mm3. The maximum tolerated dose was not reached. All patients developed a monocytosis characterized by increased expression of the antigen HLA-DR and decreased expression of CD14, a phenotype reported to represent a subpopulation of monocytes active in mediating antibody-directed cellular cytotoxicity. Other biologic effects of treatment included marked but transient decreases in total cholesterol, low density lipoprotein, and high density lipoprotein. Three patients experienced tumor regression in breast, liver, and lymph node metastases and received a second course of therapy. Six of the 19 patients, one of whom received no further therapy, survived more than 2 years and 4 of these patients remain alive 24 to 37 months after treatment. Of the six patients with liver metastases, three (50%) survived more than 2.5 years and one remains alive at 37+ months. CONCLUSIONS: Combination therapy with R24 and M-CSF resulted in both clinical and biologic effects that warrant further investigation of this combination.

CSF-1 treatment promotes angiogenesis in the metaphysis of osteopetrotic (toothless, tl) rats.

It has recently been shown that following treatment with colony-stimulating factor-1 (CSF-1) the osteopetrotic condition in toothless (tl) rats greatly improves and growth is accelerated. We have examined the effects of such treatment on the microvasculature of the distal femoral chondro-osseous junction, a site where bone growth in length is coordinated with angiogenesis. Vascular casts and ultrastructural analyses of this region showed that, compared to untreated normal rats, untreated mutants showed little bone growth or angiogenesis. When mutants were treated with CSF-1 angiogenesis was markedly accelerated. These data show a remarkable effect of this growth factor on angiogenesis in this osteopetrotic mutation. Whether this effect of CSF-1 on angiogenesis is direct or indirect is not known and indicates that its effects on the normal microvasculature deserve further study.

Phase II trial of recombinant human macrophage colony-stimulating factor in metastatic soft tissue sarcoma.

This Phase II study was undertaken to access the activity of recombinant human macrophage colony stimulating factor (M-CSF) in metastatic soft tissue sarcoma based on the observation of a partial response in a patient with leiomyosarcoma during an earlier Phase I trial. Fifteen patients with metastatic soft tissue sarcoma (seven males and eight females) were entered on the trial between October 1990 and March 1991. Seven of these patients had leiomyosarcoma. One mg/M2 of M-CSF was administered by rapid intravenous infusion every 8 h on days 1-5 and 15-19. Treatment cycles were repeated at 35-day intervals. Patients were evaluated initially for response after the first cycle, and then following alternate cycles. One partial response was observed in a patient with metastatic small bowel leiomyosarcoma (response rate 7%, 95% confidence interval, 0-33%). Two additional patients had stable disease for 10-15 months on study. Four patients had clinically significant bleeding from tumor sites during M-CSF therapy. No evidence of toxicity directly attributable to M-CSF was observed in any patient. Mean monocyte counts increased in patients during the first 20 days of treatment (p = 0.013). At this dose and schedule, meaningful activity of M-CSF in previously treated patients with soft tissue sarcoma could not be demonstrated. However, the activity observed in patients with leiomyosarcoma in this trial and in the previous Phase I study are intriguing. Further studies of M-CSF in previously untreated patients with leiomyosarcoma may be warranted.

Unique dermatological complication of rhM-CSF treatment.

A patient is presented who developed cutaneous papular histiocytic infiltrates after treatment with monocyte colony stimulating factor (rhM-CSF). This is the first reported complication of this type after treatment with this new cytokine.

Clinical use of hematopoietic growth factors in allogeneic bone marrow transplantation.

The use of the recombinant hematopoietic growth factors G-CSF and GM-CSF have shortened the period of neutropenia, or avoided this problem, in many cancer patients who have received cytotoxic therapy. Although these benefits have been particularly striking in the autologous bone marrow and/or autologous peripheral blood progenitor cell transplant setting, most data suggest that the use of G-CSF and GM-CSF only marginally enhance recovery of the neutrophil count when administered after allogeneic bone marrow infusion. Furthermore, in the allograft setting these expensive agents have not provided benefit in the form of enhanced platelet count recovery, lessening the incidence of graft-versus-host disease, or improvement in overall survival. These data do not justify routine widespread use of G-CSF and GM-CSF and suggest that these agents should be reserved for patients who experience delay in engraftment after allogeneic bone marrow infusion. Administration of erythropoietin, on the other hand, may reduce the need for homologous red blood cell transfusions, and may increase the safety margin for both the allogeneic bone marrow recipient and as well as the donor. Recombinant hematopoietic growth factors targetted specifically to enhance platelet recovery after transplantation (such as interleukin-3, interleukin-6, and interleukin-11) have shown promise after autotransplantation and after conventional dose chemotherapy, and likely will be evaluated in the allogeneic transplant patient.

Phase I trial of recombinant macrophage colony-stimulating factor and recombinant gamma-interferon: toxicity, monocytosis, and clinical effects.

Macrophage colony-stimulating factor (M-CSF) is a known inducer of proliferation and differentiation of cells of the mononuclear phagocyte lineage, and gamma-interferon (gamma-IFN) is a known activator of mononuclear phagocytes. In this Phase I clinical trial of combined therapy with M-CSF and gamma-IFN, 36 patients were treated with 14-day continuous infusions of M-CSF at doses ranging from 10 to 140 micrograms/kg/day. In all but five patients, gamma-IFN was administered by daily s.c. injection on days 8-14 of the M-CSF infusion at doses of 0.05 or 0.1 mg/m2/day. A total of 73 courses of M-CSF and 66 courses of gamma-IFN were administered. The maximally tolerated dose combination was 120 micrograms/kg/day M-CSF, 0.1 mg/m2/day gamma-IFN. The addition of gamma-IFN did not alter the maximally tolerated dose of M-CSF therapy, although some additional toxicities were noted with combined therapy. At the 140-micrograms/kg/day M-CSF dose level, grade 4 thrombocytopenia occurred in 2 of 3 patients, with a median platelet count nadir of 26,000/mm3 after 7-10 days of M-CSF infusion. At this dose level, there was one reversible grade 3 hepatic toxicity, and one grade 3 exacerbation of underlying chronic obstructive lung disease. Peripheral blood monocytosis was observed at all M-CSF dose levels exceeding 40 micrograms/kg/day, approaching 3-fold elevations at the 100-micrograms/kg/day M-CSF dose level. The induction of monocytosis was correlated with the development of thrombocytopenia. At the conclusion of therapy with 100 micrograms/kg/day M-CSF, 0.1 mg/m2/day gamma-IFN, 78% of peripheral blood monocytes expressed the low affinity Fc gamma receptor for aggregated immunoglobulin, Fc gamma RIII (CD16), and CD14 was expressed by only 36% of the cells. This phenotype has been shown previously to be associated with cellular activation. In contrast, 35% of monocytes from patients treated with M-CSF therapy alone at the same dose expressed CD16 and 88% expressed CD14. A partial clinical response was noted in a patient with metastatic renal cell carcinoma, and minor clinical responses were observed in patients with a diffuse/follicular lymphoma, metastatic renal cell carcinoma, and metastatic thymoma. At M-CSF doses exceeding 20 micrograms/kg/day within the maximally tolerated dose range, gamma-IFN did not modulate the ability of M-CSF to reliably induce peripheral blood monocytosis. This study shows that M-CSF and gamma-IFN therapy induces the proliferation and differentiation of circulating mononuclear phagocytes.

Pleiotropic effects of cytokines: clinical and preclinical studies.

Cytokines have diverse and pleiotropic effects including immunologic, hematopoietic and pro-inflammatory activities. A total of 135 patients have been treated in a series of phase I clinical trials utilizing five different recombinant cytokines: granulocyte-macrophage colony-stimulating factor (rhuGM-CSF), interleukin 3 (rhIL-3) interleukin 4 (rhuIL-4), and interleukin 6 (rhIL-6). The toxicity, maximum tolerated dose and biologic activities were determined. Hematopoietic, immunologic and pro-inflammatory effects were noted during therapy with these agents. Prominent effects on lymphocyte and monocyte functional activities were demonstrated. The diversity of biologic effects in vivo demonstrates the pleiotropic nature of the cytokines investigated and the difficulties encountered in their in vivo evaluation.

Phase I trial of subcutaneous recombinant macrophage colony-stimulating factor: clinical and immunomodulatory effects.

PURPOSE: Recombinant human macrophage colony-stimulating factor (rM-CSF) has been demonstrated to control the growth, differentiation, and function of mononuclear phagocytes. Preclinical studies have indicated antitumor effects, and therefore a phase I trial of rM-CSF in patients with malignancy was initiated. The toxicity and hematologic and immunologic effects were investigated. PATIENTS AND METHODS: rM-CSF was administered as a subcutaneous injection on days 1 through 5 and 8 through 12. Cycles were repeated every 28 days. Cohorts of four to seven patients received rM-CSF at dose levels from 0.1 to 25.6 mg/m2/d. Forty-two patients received 88 cycles of rM-CSF. All patients had metastatic solid tumors refractory to standard therapy. RESULTS: The toxicity of rM-CSF was mild. Dose-limiting toxicity included thrombocytopenia (two patients) and iritis (one patient) occurring at a dose of 25.6 mg/m2/d. Hematologic studies demonstrated dose-related monocytosis occurring routinely at doses > or = 3.2 mg/m2/d, and thrombocytopenia. Immunologic studies demonstrated enhanced secretion of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1-beta (IL-1 beta) by monocytes after in vitro stimulation with lipopolysaccharide, and increased expression of TNF-alpha mRNA at higher rM-CSF dose levels. Pharmacokinetic studies demonstrated that the systemic clearance rate of M-CSF increases during week 1 of therapy, resulting in lower blood levels of M-CSF during the second week of therapy. CONCLUSION: rM-CSF can be safely administered to patients, and has biologic activity on peripheral-blood monocytes.

Phase I trial of recombinant human macrophage colony-stimulating factor administered by continuous intravenous infusion in patients with metastatic cancer.

BACKGROUND: Macrophage colony-stimulating factor is a bone marrow-derived glycoprotein that can stimulate monocytes and macrophages, resulting in production of factors involved in immune response. In vitro and in vivo preclinical studies in animals have demonstrated that recombinant human macrophage colony-stimulating factor (rHuM-CSF) can have antitumor activity. PURPOSE: A phase I clinical trial was undertaken to evaluate the toxicity, pharmacokinetics, and immunologic effects of rHuM-CSF given by continuous intravenous infusion in patients with cancer. METHODS: Eighteen patients with metastatic solid tumors refractory to conventional therapy were treated with rHuM-CSF. Twelve patients received two 14-day cycles of rHuM-CSF by continuous infusion, with a 2-week interval. Dose escalation levels were 50, 100, and 150 micrograms/kg over 24 hours. Consecutive cohorts of three to six patients were planned at each dose level. Six patients received a modified regimen of four 7-day periods of infusion at 100 micrograms/kg over 24 hours, with 1-week intervals. RESULTS: Dose-limiting toxicity was grade 4 thrombocytopenia at a dose of 150 micrograms/kg over 24 hours in two patients receiving the 2-week regimen. Platelet count nadirs and concomitant monocytosis were seen on days 7-9, but recovery occurred during the treatment period. Macrophage colony-stimulating factor serum levels were maximal on day 1 and returned to near baseline on day 7 of infusion. Patients treated with four 7-day infusions had no treatment-limiting thrombocytopenia. There were no cumulative effects on platelet or monocyte counts or significant constitutional symptoms. Subclinical conjunctival injection was noted in five of 10 patients receiving screening ophthalmologic evaluation. Grade 2 episcleritis was diagnosed in one patient, and asymptomatic perilimbal and retinal hemorrhages were seen in two. Two patients developed sepsis caused by the intravenous line, which required cessation of therapy. No objective responses were documented. CONCLUSION: The maximum tolerated dose of rHuM-CSF given by continuous intravenous infusion for 14 days was 100 micrograms/kg over 24 hours, with rapidly reversible, dose-limiting thrombocytopenia at 150 micrograms/kg over 24 hours. A regimen alternating weekly cycles of infusion avoids dose-limiting toxicity and allows long-term treatment. IMPLICATIONS: The regimen of repeated 7-day infusions may be useful for future studies evaluating rHuM-CSF-activated monocytes in therapy for long-term infectious diseases or in investigation of new modes of cancer therapy using rHuM-CSF in conjunction with a tumor-specific antibody.