Comparison of neutrophil and monocyte function by microbicidal cell-kill assay in patients with cancer receiving granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, or no cytokine after cytotoxic chemotherapy: a phase II trial

Sargramostim (rhu GM-CSF) as Cancer Therapy (Systematic Review) and An Immunomodulator. A Drug Before Its Time?

BACKGROUND

Sargramostim [recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF)] was approved by US FDA in 1991 to accelerate bone marrow recovery in diverse settings of bone marrow failure and is designated on the list of FDA Essential Medicines, Medical Countermeasures, and Critical Inputs. Other important biological activities including accelerating tissue repair and modulating host immunity to infection and cancer via the innate and adaptive immune systems are reported in pre-clinical models but incompletely studied in humans.

OBJECTIVE

Assess safety and efficacy of sargramostim in cancer and other diverse experimental and clinical settings.

METHODS AND RESULTS

We systematically reviewed PubMed, Cochrane and TRIP databases for clinical data on sargramostim in cancer. In a variety of settings, sargramostim after exposure to bone marrow-suppressing agents accelerated hematologic recovery resulting in fewer infections, less therapy-related toxicity and sometimes improved survival. As an immune modulator, sargramostim also enhanced anti-cancer responses in solid cancers when combined with conventional therapies, for example with immune checkpoint inhibitors and monoclonal antibodies.

CONCLUSIONS

Sargramostim accelerates hematologic recovery in diverse clinical settings and enhances anti-cancer responses with a favorable safety profile. Uses other than in hematologic recovery are less-well studied; more data are needed on immune-enhancing benefits. We envision significantly expanded use of sargramostim in varied immune settings. Sargramostim has the potential to reverse the immune suppression associated with sepsis, trauma, acute respiratory distress syndrome (ARDS) and COVID-19. Further, sargramostim therapy has been promising in the adjuvant setting with vaccines and for anti-microbial-resistant infections and treating autoimmune pulmonary alveolar proteinosis and gastrointestinal, peripheral arterial and neuro-inflammatory diseases. It also may be useful as an adjuvant in anti-cancer immunotherapy.

Formulation of sustained-release microspheres of granulocyte macrophage colony stimulating factor by freezing-induced phase separation with dextran and encapsulation with blended polymers

This study aimed to assess the potential merits of formulating sustained-release microspheres of recombinant human granulocyte macrophage colony stimulating factor (rhGM-CSF) via freezing-induced phase separation (FIPS) of the protein with dextran followed by encapsulation with binary mixture of poly(lactic-co-glycolic acid) (PLGA) 2A (MW∼12K) and 3A (MW∼47K) or of PLGA2A and polylactic acid (PLA; MW∼83K). The formulated dextran particles and microspheres were characterized in vitro for loading, aggregation, bioactivity and release behavior of the protein where appropriate. rhGM-CSF retained about 60% of bioactivity with no significant aggregation after each formulation step. Encapsulation of protein-loaded dextran particles attained only 80% with the PLGA2A and PLGA3A blend, but 100% with the PLGA2A and PLA mixture. The former formulation exhibited a triphasic in-vitro release profile typical of PLGA microspheres while the latter revealed a much lower initial burst followed by a steady and complete release of rhGM-CSF with preserved bioactivity over a 15-day period.

Modulation of proinflammatory responses to Pneumocystis carinii f. sp. muris in neonatal mice by granulocyte-macrophage colony-stimulating factor and IL-4: role of APCs

Clearance of Pneumocystis carinii f. sp. muris (PC) organisms from the lungs of neonatal mice is delayed due to failure of initiation of inflammation over the first 3 wk after infection. The ability of neonatal lung CD11c(+) dendritic cells (DCs) to induce Ag-specific T cell proliferative responses was significantly reduced compared with adult lung DCs. However, neonatal bone marrow-derived DCs were as competent at presenting PC Ag as were adult bone marrow-derived DCs. Because GM-CSF mRNA expression and activity were significantly reduced in neonatal lungs compared with adults, we treated neonates with exogenous GM-CSF and IL-4 and found enhanced clearance of PC compared with untreated neonates. This was associated with increased lung TNF-alpha, IL-12p35, and IL-18 mRNA expression, indicating enhanced innate immune responses. Cytokine-treated mice had marked expansion of CD11c(+) DCs with up-regulated MHC-II in the lungs. Moreover, increased numbers of activated CD4(+)CD44(high)CD62L(low) cells in the lungs and draining lymph nodes suggested improved Ag presentation by the APCs. Together these data indicate that neonatal lungs lack maturation factors for efficient cellular functioning, including APC maturation.

Granulocyte colony-stimulating factor and other cytokines in antifungal therapy

Invasive fungal infections (IFIs) have emerged as a serious threat in immunocompromised patients during the last two decades. Host defenses including appropriate cytokine responses and intact phagocytic function are necessary to combat IFIs. Several cytokines have been investigated and developed for preventive and therapeutic use. Among them, granulocyte colony-stimulating factor (G-CSF) has been mostly studied and used for various purposes, the most important being the faster recovery from neutropenia. Other cytokines with potential clinical significance in relation to IFI are granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-gamma (IFN-gamma) and macrophage colony-stimulating factor. Supported by a large number of preclinical studies but limited clinical results their potential utility against IFI has been suggested. In this review, certain questions related to this issue are discussed based on data already available and an attempt to consider future research is made.

Immunotherapy in patients with systemic mycoses: a promising adjunct

Evidence from several in vitro and animal model studies suggests a modulatory role of haemopoietic, T(H)1 and T(H)2 cytokines in host defence against fungi, and highlights their potential utility as adjunctive therapy for management of systemic mycoses (SM). However, there are limited clinical data to support the use of cytokines in prevention and treatment of SM. Thus, at present no adjunctive treatment is justified for routine use in all patients. Potential application of these immunomodulatory agents include the use of granulocyte-macrophage colony-stimulating factor or macrophage colony-stimulating factor in the management of mycoses in neutropenic patients with myelogenous leukaemia or bone marrow transplantation. Interferon-gamma may have a useful role against aspergillosis in patients with chronic granulomatous disease. Granulocyte colony-stimulating factor-elicited white blood cell transfusions may be life saving to patients with refractory SM. Better understanding of synergy between cytokines and specific antifungals may provide powerful tools for managing these serious infections.

A randomized trial of granulocyte-macrophage colony-stimulating factor in neonates with sepsis and neutropenia

OBJECTIVES

To determine whether adjunctive therapy with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) could reverse sepsis-associated neonatal neutropenia and improve neonatal survival and to assess its safety compared with conventional therapy in a control group.

STUDY DESIGN

This prospective, randomized, controlled trial was performed in 60 infants with neutropenia and clinical signs of sepsis. A subcutaneous injection of rhGM-CSF (5 microgram/kg/day) was administered to 30 of the patients for 7 consecutive days. Hematologic parameters (absolute neutrophil, eosinophil, monocyte, lymphocyte counts, and platelet number) and outcome were compared with 30 conventionally treated (control) patients.

RESULTS

Twenty-five patients from the GM-CSF-treated group and 24 from the conventionally treated group had early-onset sepsis (</=3 days' postnatal age), and the other 11 patients had late-onset sepsis (>3 days' postnatal age). There was no difference between groups in terms of birth weight; gestational age; gender; maturity; maternal age; and incidence of prolonged rupture of membranes, maternal hypertension, or severity of sepsis. All neonates tolerated GM-CSF well with no adverse reactions. The absolute neutrophil count on day 7 was significantly increased in the GM-CSF-treated group compared with the conventionally treated group: 8088 +/- 2822/mm(3) versus 2757 +/- 823/mm(3). The mean platelet count was significantly higher on days 14 in the GM-CSF-treated group compared with conventionally treated group: 266 867 +/- 55 102/mm(3) versus 229 200 +/- 52 317/mm(3). Hematologic parameters were otherwise similar between groups before treatment and on day 28. Twenty-seven neonates in the rh-GMCSF group and 21 in the control group survived to hospital discharge. The mortality rate in the rhGM-CSF group (10%) was significantly lower than in the conventionally treated group (30%).

CONCLUSION

Treatment with rhGM-CSF is associated with an increase in absolute neutrophil, eosinophil, monocyte, lymphocyte, and platelet counts and decreased mortality in critically ill septic neutropenic neonates. These results suggest that rhGM-CSF may be effective in the treatment of neonatal sepsis with neutropenia, and further randomized trials are needed to confirm its beneficial effects.

A randomized, controlled trial of prophylactic granulocyte-macrophage colony-stimulating factor in human newborns less than 32 weeks gestation

OBJECTIVE

Preterm neonates undergoing intensive care have high morbidity from sepsis. These infants also frequently develop neutropenia, and when this is associated with sepsis, mortality is high. This study investigates the potential for granulocyte-macrophage colony-stimulating factor (GM-CSF) to effect a clinically relevant increase in neutrophil number when used prophylactically in high-risk preterm neonates, and assesses its safety in this population.

DESIGN

In an open, randomized, controlled study, 75 neonates (25 small for gestational age) <32 weeks gestation were randomized to receive GM-CSF (10 microg/kg/d) by subcutaneous injection for 5 days from <72 hours after birth, or to a control group. The primary outcome measure was the neutrophil count during 14 days from study entry. The infants were monitored for potential toxicity. Clinical outcomes, sepsis, and mortality, were recorded, but this initial study was not designed to address clinical benefit.

RESULTS

Prophylactic GM-CSF therapy completely abolished neutropenia in treated infants, when both well and septic, throughout the period of study. Neutropenia (</=1.7 x 10(9)/L) developed in 16 of 39 control infants. Five control infants experienced an acute decrease in neutrophil count coincident with the onset of sepsis. There was no evidence of hematologic, respiratory, or gastrointestinal toxicity in treated infants. Treated infants had a trend to fewer symptomatic, blood culture positive septic episodes than controls during 2 weeks from study entry (11/36 vs 18/39).

CONCLUSION

Five-day prophylactic GM-CSF completely abolishes postnatal neutropenia and sepsis-induced neutropenia in preterm neonates at high risk of sepsis, and so removes an important risk factor for sepsis and sepsis-related mortality.GM-CSF, preterm neonates, neutropenia, sepsis.