Granulocyte-macrophage colony-stimulating factor mitigates the neutropenia of combined interferon alfa and zidovudine treatment of acquired immune deficiency syndrome-associated Kaposi's sarcoma

Interferon-alpha2b with protease inhibitor-based antiretroviral therapy in patients with AIDS-associated Kaposi sarcoma: an AIDS malignancy consortium phase I trial

We evaluated the safety and maximum tolerated dose of interferon (IFN)-alpha2b in combination with protease inhibitor-based highly active antiretroviral therapy (HAART) in a phase 1 study in 14 patients with AIDS-associated Kaposi sarcoma (KS). Planned IFN dose levels were 0, 1, 5, 10, and 15 million IU administered by daily subcutaneous injection. Dose-limiting toxicities were neutropenia and malaise. The maximum tolerated IFN dose was 5 million IU/d. The median CD4 count increased from 260 cells/muL at baseline to a maximum on-study value of 359 cells/muL. In 6 patients with paired baseline and on-study values, the median HIV RNA level decreased from 20,179 copies/mL to a minimum on-study value of 309 copies/mL. Of 13 patients whose KS response could be evaluated, 5 showed objective tumor regression. Responses occurred in HAART-experienced and HAART-naive subjects. Five patients, including 2 responders, 2 with stable KS, and 1 with progression, had serial measurements of Kaposi sarcoma herpesvirus (KSHV) load. None of these patients, irrespective of treatment arm or KS response, showed durable clearance of KSHV from plasma or peripheral blood mononuclear cells. This study establishes a safe dose of IFN that can be used with HAART and, potentially, with other inhibitors of KS in future clinical trials.

Granulocyte-macrophage colony-stimulating factor as an immune-based therapy in HIV infection

The HIV/AIDS epidemic continues to spread despite more than 20 years of significant research and major advances in its treatment. The introduction of highly active antiretroviral therapy in recent years has significantly improved disease treatment with a dramatic impact in HIV/AIDS associated morbidity and mortality in countries which have access to this therapy. Despite these advances, such therapies are imperfect and other therapeutic modalities, including immune-based therapies, are being actively sought. Potential benefits of immune-based therapies include: 1) the improvement of HIV-specific immunity to enhance control of viral replication, 2) the improvement of other aspects of host immunity in order to prevent or delay the development of opportunistic infections and 3) the potential to purge virus from cellular reservoirs which are sustained despite the effects of potent antiretroviral therapy. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been studied as one of these immune-based therapies. Several randomized, controlled trials have demonstrated benefits of using GM-CSF as an adjunct to conventional anti-retroviral therapy, although such benefits have not been universally observed. Individual studies have shown that GM-CSF increases CD4+ T cells counts and may be associated with decreased plasma HIV RNA levels. There is limited evidence that GM-CSF may help prevent the emergence of antiretroviral drug resistant viruses and that it may decrease the risk of infection in advanced HIV disease. Despite its high costs and the need to be administered subcutaneously, encouraging results continue to emerge from further studies, suggesting that GM-CSF has the potential to become an effective agent in the treatment of HIV infection.

Biological and clinical basis for molecular studies of interferons

The cytokine family of interferons (IFNs) has multiple functions, including antiviral, anti-tumor, and immunomodulatory effects and regulation of cell differentiation. The multiple functions of the IFN system are thought to be an innate defense against microbes and foreign substances. The IFN system consists first of cells that produce IFNs in response to viral infection or other foreign stimuli and second of cells that establish the antiviral state in response to IFNs. This process of innate immunity involves multiple signaling mechanisms and activation of various host genes. Viruses have evolved to develop mechanisms that circumvent this system. IFNs have also been used clinically in the treatment of viral diseases. Improved treatments will be possible with better understanding of the IFN system and its interactions with viral factors. In addition, IFNs have direct and indirect effects on tumor cell proliferation, effector leukocytes and on apoptosis and have been used in the treatment of some cancers. Improved knowledge of how IFNs affect tumors and the mechanism that lead to a lack of response to IFNs would help the development of better IFN treatments for malignancies.

Management of Kaposi sarcoma: the role of interferon and thalidomide

Kaposi sarcoma (KS) remains the most commonly diagnosed cancer in HIV-infected patients. Although several chemotherapeutic agents have proven effective in controlling KS, the growing understanding of the factors contributing to the development of KS has provided a stronger rationale for using noncytotoxic agents that influence the mechanisms involved in KS pathogenesis. Two such agents, interferon and thalidomide, have shown activity against KS in clinical trials and have the potential to influence multiple steps believed to be important in KS development and progression. Studies are ongoing to explore the optimal way to use these agents and their mechanisms of action.

Interferon in oncological practice: review of interferon biology, clinical applications, and toxicities

For the past 40 years, various forms of interferon (IFN) have been evaluated as therapy in a number of malignant and non-malignant diseases. With the advent of gene cloning, large quantities of pure IFN became available for clinical study. This paper reviews the biology, pharmacology, and clinical applications of IFN formulations most commonly used in oncology. It then reviews the most common side effects seen in patients treated with IFN, and makes recommendations for the management of IFN-induced toxicity. The major oncological indications for IFN include melanoma, renal cell carcinoma, AIDS-related Kaposi's sarcoma, follicular lymphoma, hairy cell leukemia, and chronic myelogenous leukemia. Unfortunately, IFN therapy is associated with significant toxicity, which can be divided into constitutional, neuropsychiatric, hematologic, and hepatic effects. These toxicities have a major impact on the patient's quality of life, and on the physician's ability to optimally treat the patient. Careful attention to all aspects of patient care can result in improved tolerability of this difficult but promising therapy.

CONCLUSION

a better understanding of IFN biology, indications, side effect profiles, and toxicity management will aid in optimizing its use in the treatment of patients with cancer.

Colony-Stimulating Factors in Stem Cell Transplantation: Effect on Quality of Life

Health-related quality of life (QOL) is poorest during the immediate post-transplantation period, but the impact of medical interventions during this period has not been studied. Colony-stimulating factors (CSFs), which are used to minimize short-term negative outcomes, might be expected to improve QOL; however, little is published about their impact on QOL during this period. We conducted a MEDLINE search to identify studies reporting on outcomes of stem cell transplantation (SCT) affected by the CSFs, mainly sargramostim and filgrastim. End points studied were: mucositis, incidence and type of infection, duration of hospitalization, time to myeloid engraftment, and quantity and quality of harvested cells. To impute the impact of CSFs on QOL post-SCT, we also reviewed the association between QOL and CSF outcomes in other circumstances. Data suggest that both CSFs improve QOL in the early autologous or allogeneic post-bone marrow transplantation period. Poor QOL caused by infection and increased length of hospital stay is expected to be improved by sargramostim. Time to myeloid engraftment, when negatively affecting QOL, is expected to be improved with both CSFs; however, the time to myeloid engraftment is consistently shorter with filgrastim. Current prospective trials designed to study the effects of CSFs in the immediate post-SCT period should collect QOL data.

Interferon-alpha: evolving therapy for AIDS-associated Kaposi's sarcoma

This article reviews developments over nearly 15 years in the application of interferon-alpha (IFN-alpha) to the treatment of Kaposi's sarcoma (KS) in patients with acquired immunodeficiency syndrome (AIDS). The initial success of IFN treatment for selected patients with AIDS-associated KS occurred before identification of the human immunodeficiency virus (HIV) and in the absence of any coherent view of KS pathogenesis. A more comprehensive understanding of the biology of both AIDS and KS, together with increased knowledge of the biologic effects of IFN and therapeutic advances in the treatment of HIV infection, have made IFN therapy for KS both more rational and more successful. There is every reason to believe that the current results with IFN for KS can be improved on by capitalizing on recent improvements in HIV therapy and the availability of specific inhibitors of angiogenic cytokines. I sincerely thank the Milstein family and my colleagues in the International Society for Interferon and Cytokine Research (ISICR) for recognizing this work, which is the product of many collaborations between clinical and basic scientists in my own institution and elsewhere.

Hematologic complications of human immunodeficiency virus infection and the acquired immunodeficiency syndrome

The hematologic manifestations of HIV infection and AIDS are common and may cause symptoms that are life-threatening and impair the quality of life of these patients. The most important of these manifestations are cytopenias. Anemia and neutropenia are generally caused by inadequate production because of suppression of the bone marrow by the HIV infection through abnormal cytokine expression and alteration of the bone marrow microenvironment. Thrombocytopenia is caused by immune-mediated destruction of the platelets, in addition to inadequate platelet production. The incidence and severity of cytopenia are generally correlated to the stage of the HIV infection. Other causes of cytopenia in these patients include adverse effects of drug therapy, the secondary effects of opportunistic infections or malignancies, or other preexisting or coexisting medical problems that may be prevalent in the HIV-infected population. Diagnosis of the mechanism and cause of the cytopenia may allow for specific management. Optimal management of the underlying HIV infection is essential, and mild cytopenia in asymptomatic patients may need no specific management. Supportive care for anemia includes the use of erythropoietin in addition to the judicious use of red blood cell transfusions. Therapy for neutropenia includes the use of the myeloid growth factors G-CSF and GM-CSF. Immune-mediated thrombocytopenia may be treated with a combination of zidovudine, corticosteroids, IVGG, and splenectomy. Platelet transfusions are sometimes needed for the treatment of thrombocytopenia caused by decreased production. Other hematologic manifestations such as hypergammaglobulinemia and lupus anticoagulants are commonly asymptomatic and usually require no specific therapy, but they can rarely cause morbidity and require specific interventions.

Acquired immunodeficiency syndrome-associated Kaposi's sarcoma. Biology and management

Kaposi's Sarcoma (KS), the most common AIDS-associated malignancy, occurs with increased frequency in all HIV transmission groups, but at a particularly high rate in homosexual men. Recent studies suggest that KS pathogenesis involves exposure to an infectious agent, altered expression and response to cytokines, and modulation of growth by HIV gene products. KS varies in its clinical presentation from a relatively indolent process to a widely disseminated, aggressive disease. A variety of local and systemic treatments provide effective, but usually temporary, disease palliation. Insights into KS pathogenesis suggest a number of targeted therapeutic approaches that may eventually lead to improved disease management and disease cure.

Kaposi's sarcoma and its management in AIDS patients. Recommendations from a Scandinavian Study Group

KS is the most frequent malignancy in homo/bisexual male AIDS patients, affecting more than 30% of these patients. KS may present itself as a few innocent cutaneous lesions or may show progression resulting in severe morbidity and mortality. Approximately half of the patients may develop severe progressive disease. The prognosis of patients with progressive disease is poor, with a median survival of less than 6 months. There is no cure for AIDS-related KS, but several therapies are available for palliation. The treatment options may be applied locally or systemically. Radiotherapy is efficacious and safe, but only a few lesions may be treated at one time. For severe progressive KS, systemic therapy with various forms of chemotherapy is used. Three regimes in particular have been focused on, namely bleomycin/vincristine (BV), doxorubicin + BV (DBV), or liposomal daunorubicin (LD) administered every 2 weeks. The agents result in a clinically relevant response (in 50-80% of patients) 2-4 weeks after initiation, but few patients have complete remission of the KS (< 10%), and the tumour may relapse after 4-6 months despite continued therapy. BV is less effective but also less toxic compared with the other regimens. Time to response for DBV may be slightly better than for LD, but the overall efficacy of these 2 regimes is similar. LD treatment is associated with significantly fewer episodes of peripheral neuropathy and alopecia than treatment with DBV. Thus, the recommended order of use of chemotherapeutic agents is BV, LD and DBV. Alpha-interferon may have a role in the small percentage of patients with CD4 cell count > 200 mill/L. In conclusion, several therapeutic options are available for palliation of KS. All systemically applied therapies are associated with severe side-effects and the optimal choice of treatment is a careful balance between response and toxicity. The recent discovery of human herpes virus 8 as a putative causative agent for KS and new potent groups of anti-retroviral agents, may lead to the development of more effective treatments of KS.

Hematologic disorders and growth factor support in HIV infection

During the course of HIV disease a broad spectrum of hematologic disorders develop including abnormalities in blood cell generation, survival, and function Alterations in coagulation parameters may evolve associated with disruption of immunoglobulin or factor production. This article reviews the manifestations and pathophysiology of these abnormalities and discusses the role for growth factor support.

AIDS-related Kaposi's sarcoma. A template for the translation of molecular pathogenesis into targeted therapeutic approaches

AIDS-related Kaposi's sarcoma (KS) represents a complex interaction of host and viral factors. There are a number of fundamental questions surrounding the interplay between the disparate factors that can contribute to the pathogenesis and pathophysiology of this disease. Targets such as the enhancement of immune function, inhibition of angiogenic factors or immunostimulatory cytokines, inhibition of viral proteins such as Tat, or hormonal manipulations are now or will in the future become the focus of research to develop innovative anti-KS therapy and prevention measures. Antiviral approaches aimed at HIV or other viruses may potentially target a number of steps in KS pathogenesis. This article reviews diverse modalities--cytotoxic, antiviral, gene-directed, growth factor-targeted, and antiangiogenesis--that singly, or more likely in combination, stand to make an impact on the cure and prevention of AIDS-related KS.

Overview of the management of AIDS-related Kaposi's sarcoma

OBJECTIVE

To review the epidemiology, pathogenesis, clinical presentation, diagnosis, and staging of Kaposi's sarcoma (KS), as well as the current role of local and systemic therapies in the management of AIDS-related KS (AIDS-KS).

DATA SOURCES AND STUDY SELECTION

MEDLINE and CANCERLIT searches of the English-language medical literature were conducted. Emphasis was placed on studies published since the onset of the AIDS epidemic in the early 1980s. A manual review of selected bibliographies was also completed.

DATA SYNTHESIS

AIDS-KS is a disease with a heterogeneous presentation that affects approximately 20% of patients with AIDS. Although the proportion of AIDS patients developing this disease during the course of their illness is declining, the actual number of AIDS-KS cases is increasing. The etiology of AIDS-KS is not clear, but a sexually transmitted cofactor has been implicated. Recent reports demonstrate that a herpes-like virus may be responsible for the development of KS in patients with and without AIDS. Furthermore, the cellular origin of KS has not been identified and questions remain about whether KS represents a true malignancy. The system used in staging patients with AIDS-KS has changed dramatically since initial therapeutic trials were conducted; this may account for observed differences in outcome among trials. The immunologic status of patients is now included as part of the staging system, since it has prognostic significance. Since specific therapy for AIDS-KS is not curative and does not prolong survival, it should be directed at improving patient cosmesis and palliation of disease-related symptoms. Local therapy, such as radiation, cryotherapy, and intralesional chemotherapy, is recommended for the management of limited disease. Systemic interferon alfa or chemotherapy is indicated for disseminated disease. Interferon alfa is useful in patients with predominantly mucocutaneous disease and is most effective in patients with good prognostic factors, such as absence of B symptoms, no history of opportunistic infections, and a CD4 count of more than 200 cells/mm3. Interferon alfa alone or in combination with zidovudine produces responses in approximately 30% of AIDS-KS patients with good prognostic factors. Single-agent or combination chemotherapy is indicated for rapidly progressive or advanced AIDS-KS. Commonly used agents include doxorubicin, daunorubicin, bleomycin, vincristine, and vinblastine. Responses can be expected in at least 50% of patients treated with single-agent or combination chemotherapy. However, many patients are unable to tolerate the toxicity associated with systemic AIDS-KS therapy. Future research will focus on therapies that target the underlying pathogenesis of this disease.

CONCLUSIONS

The optimal therapy for patients with AIDS-KS has not been determined. Treatment is appropriately directed at palliation of disease-related symptoms as no therapy has been unequivocally proven to impact survival. Local therapies should be used in the management of localized disease, while systemic therapy is appropriate for disseminated disease. Interferon alfa is useful in patients with primarily mucocutaneous disease or asymptomatic visceral involvement. Chemotherapy is indicated in patients who have rapidly progressive or advanced disease. Therapy must be individualized according to the patient's disease course and other patient-specific factors.

Treatment of HIV infection. Tolerability of commonly used antiretroviral agents

There are a number of agents available that are active against HIV. Eight drugs are already licensed in the US: the nucleoside analogue reverse transcriptase inhibitors--zidovudine, didanosine, zalcitabine, stavudine and lamivudine--and the HIV protease inhibitors--saquinavir, indinavir and ritonavir. Antiretroviral drugs have been given as monotherapy, often as sequential monotherapy, and in alternating or simultaneous combinations. Since combination therapy has recently been shown to be superior to monotherapy, antiretrovirals will increasingly be given in combination. All available antiretroviral drugs show considerable toxicity complicating their use. In this article we describe the adverse effects of the above mentioned nucleoside analogues used in monotherapy and of several combinations of antiretroviral drugs. No unexpected toxicities were found in several different combinations tested to date and, for most combinations, no synergistic toxic effects have been reported.

Lack of in vivo effect of granulocyte-macrophage colony-stimulating factor on human immunodeficiency virus type 1

Neutropenia complicates HIV disease or its treatment in a large proportion of patients. Hematopoietic growth factor support has been tested in a number of clinical settings in HIV disease and has been demonstrated to be of benefit for specific parameters. One consideration regarding the use of hematopoietic growth factors in HIV disease is their potential effect on HIV viral burden, since alterations in HIV expression have been documented with certain cytokines in vitro. It has also been reported that some cytokines, notably GM-CSF, potentiate the antiviral properties of thymidine analogs such as zidovudine (AZT) in vitro. We tested these observations in vivo. Twelve HIV-positive patients with a CD4 cell count < or = 200/mm3 or HIV plasma viremia who were receiving a stable dose of zidovudine were enrolled into three dose cohorts of yeast-derived GM-CSF at 50, 125, or 250 micrograms/m2 daily by subcutaneous self-injection for 28 days. Measurements of HIV activity included serum acid-dissociated HIV p24 antigen levels, plasma and peripheral blood mononuclear cell (PBMC) limiting dilution HIV culture, and plasma HIV quantitative competitive polymerase chain reaction (PCR). Serum and intracellular zidovudine levels were measured as well as hematologic, immunologic, and toxicity parameters. Virologic measures showed neither significant upregulation nor downregulation of serum acid-dissociated HIV p24 antigen, plasma and PBMC HIV culture, or PCR in association with GM-CSF administration. A trend toward increased intracellular AZT levels was noted, but this did not achieve statistical significance (p = 0.073). CD4 and CD8 lymphocytes were essentially unaffected while absolute neutrophil counts increased with GM-CSF administration as expected. These data suggest that administration of GM-CSF does not perturb HIV activity or immunologic parameters in patients receiving AZT for advanced HIV disease. No potentiation of AZT antiviral effect was demonstrated.

Chemotherapy combined with zidovudine and GM-CSF in human immunodeficiency virus-related non-Hodgkin's lymphoma

OBJECTIVE

The treatment of patients with non-Hodgkin's lymphoma related to the human immunodeficiency virus (HIV-NHL) is complicated by the underlying acquired immunodeficiency syndrome (AIDS). Patients without adverse prognostic factors (no AIDS prior to lymphoma, CD4+ lymphocyte counts greater than 100 x 10(6)/l and good performance status) can be cured of lymphoma and experience long-term survival. Our previous study with the intensive chemotherapy LNH84 regimen yielded a 63% complete response (CR) rate but median survival was only nine months, half of the patients died of AIDS and the other half of their lymphoma. We report here the results of a phase II study combining the same chemotherapy with zidovudine and GM-CSF. Our goal was to improve the treatment outcome over that of our previous study; GM-CSF was expected to decrease the hematological toxicity of chemotherapy and thus permit a dose intensity increase, while zidovudine was supposed to slow down the evolution of AIDS.

DESIGN AND SETTING

A phase II non-randomized prospective clinical trial in 7 centres.

PATIENTS AND METHODS

Thirty-two consecutive adult patients presenting HIV-NHL and performance status of less than three without active opportunistic infection underwent three cycles of doxorubicin 75 mg/m2, cyclophosphamide 1,200 mg/m2, vindesine 2 mg/m2 for two days, bleomycin 10 mg for two days and prednisolone 60 mg/m2 for five days (ACVB). Chemotherapy was associated with zidovudine (5 mg/kg/d) and GM-CSF (5 mu g/kg/d). The induction phase was followed by a four-month consolidation phase.

RESULTS

CR and PR > 75% were observed in 56% of patients; 25% of the patients died during the induction phase. These results were analogous to those of the previous study (63% and 14%, respectively). Neither hematological tolerance nor dose intensity were improved. With a mean follow-up of 23.5 months, median survival was 6.7 months. The rate of non-NHL AIDS-related death during CR was not reduced (22% in our study vs. 16% in our previous one).

CONCLUSIONS

GM-CSF failed to reduce significantly the cumulative hematological toxicity of chemotherapy and zidovudine. New antiviral agents without hematological toxicity would perhaps be useful in this setting.

In vivo effects of interleukin 3 in HIV type 1-infected patients with cytopenia

OBJECTIVE

To determine the safety, tolerance, and hematological and virological effects of the recombinant hematopoietic growth factor interleukin 3 (IL-3) in HIV-1-infected individuals with cytopenia.

DESIGN AND METHODS

A phase I single-center trial was conducted with patients in cohorts of three receiving one of four dose levels of self-administered, subcutaneously injected IL-3 (0.5, 1.0, 2.5, or 5.0 micrograms/kg/day). Toxicities, hematological effects, and virological effects were recorded. Viral studies included serum HIV p24 antigen levels, quantitative plasma and peripheral blood mononuclear cell cultures, and quantitative, competitive polymerase chain reaction of patient plasma.

RESULTS

Increases in white blood cell counts (WBC) and absolute neutrophil counts (ANC) were noted at the higher dose levels while absolute eosinophil counts (AEC) increased in all patients. The percent changes in WBC from baseline ranged from 52 to 309 and in ANC from 20 to 262 in the 2.5- and 5.0-micrograms/kg/day groups. The mean AEC change was 17-fold (range, 2- to 59-fold). Hemoglobin, hematocrit, platelets, and CD4 and CD8 counts were generally unaffected although individual patients demonstrated increases in hemoglobin and platelet levels. Toxicities were generally mild, but one patient developed a transient local erythematous rash at the sites of IL-3 injection which pathologically demonstrated hypersensitivity vasculitis. Of note, viral studies did not demonstrate any consistent changes in HIV-1 activity.

CONCLUSION

These data demonstrate limited hematological effects of IL-3 monotherapy in HIV-1-infected patients with cytopenia. However, should IL-3 be incorporated into combination cytokine therapies for HIV disease, these data suggest that IL-3 does not enhance in vivo HIV-1 activity.

Perspectives of cytokine treatment in malignant skin tumors

Cytokines have been tested in the treatment of different skin cancers during the last decade, and treatment schedules have been established or proposed for several malignant skin tumors. Preferentially, the interferons and interleukin-2 were found to be effective in treating skin cancers. Interferons alpha and beta have been approved for the treatment of human immunodeficiency virus (HIV)-associated Kaposi's sarcoma, cutaneous T cell lymphoma, and malignant melanoma in several countries. Interferon alpha was found to be most effective in cutaneous T cell lymphoma with 40%-60% overall responses. When combining interferon alpha with psoralens and ultraviolet A (PUVA) or with retinoids, even higher response rates up to 60%-90% were reported, and long-term remissions have been described. A considerable activity of interferon alpha was found in HIV-associated Kaposi's sarcoma with response rates of 30%-50%. The effectiveness of Kaposi's sarcoma's treatment was further improved by combining interferon alpha and zidovudine. Responses to interferon alpha in metastatic malignant melanoma are rather seldom (10%-15%), but a stabilization of the disease with prolonged survival was reported after interferon alpha treatment. Additionally, interleukin-2 was found to be active in metastatic melanoma, with overall response rates of about 20%, and both biological agents were found to have an additive efficacy in combination. Several combined regimens of interferon alpha, interleukin-2, and polychemotherapy have been described in metastatic melanoma, and overall response rates higher than 50% were found with these combined treatment modalities. Interferon alpha and beta were also intralesionally injected into basal cell carcinomas and other epithelial skin cancers, and complete responses were found in more than 80% of tumors treated. Local applications of interferons and interleukin-2 were likewise found to be effective in the treatment of cutaneous melanoma metastases and cutaneous manifestations of Kaposi's sarcoma. Cytokines and their combination with other treatment modalities has greatly enriched the treatment facilities in malignant skin tumors during recent years, and additional new cytokines will be introduced in skin cancer treatment in near future.

Mechanisms of cytopenia in human immunodeficiency virus infection

Human immunodeficiency virus (HIV) infection often has effects on the hematopoietic system which can be distinguished from the concurrent effects of medications or opportunistic infections. Exactly how the virus mediates these effects remains uncertain, but both in vivo and in vitro studies have pointed up possible direct and indirect modes of hematopoietic suppression. Whether a significant fraction of CD34+ cells in vivo are infected with HIV remains controversial, but most studies using in situ polymerase chain reaction techniques would suggest not. Other more indirect modes of hematopoietic cell suppression such as production of autoantibodies, production of other humoral inhibitory factors, T-cell mediated suppression of hematopoiesis, or production of inhibitory or stimulatory cytokines may also be contributory. It is probable that several of these mechanisms may occur simultaneously, and an increased understanding of their role may lead to improved strategies to correct the cytopenias which often accompany HIV disease.

Combination of ganciclovir and granulocyte-macrophage colony-stimulating factor in the treatment of cytomegalovirus retinitis in AIDS patients. The ACTG 073 Team

The efficacy and safety of a combination of ganciclovir plus GM-CSF was evaluated in AIDS patients with cytomegalovirus retinitis. In phase A, patients were randomized to receive ganciclovir, 5 mg/kg every 12 h for 14 days followed by 5 mg/kg daily, with (n = 24) or without (n = 29) GM-CSF (1-8 micrograms/kg daily subcutaneously) to maintain absolute neutrophil counts between 2500 and 5000 cells/microliters. In phase B, after 16 weeks zidovudine was added to the regimen of 16 patients receiving ganciclovir plus GM-CSF and 20 receiving ganciclovir alone. At this stage, GM-CSF was added to the treatment protocol of any patient receiving ganciclovir plus zidovudine who became neutropenic. In phase A, patients in the ganciclovir plus GM-CSF group had significantly higher neutrophil counts than ganciclovir-alone patients (p = 0.0001). Overall, 12.5% of patients treated with GM-CSF developed neutropenia (absolute neutrophil counts < 500/microliters phase A and < 750/microliters phase B) compared with 45% of patients treated without GM-CSF. GM-CSF patients missed 10 of a possible 4705 scheduled doses of ganciclovir compared with 34 missed doses of a possible 6584 in the ganciclovir-alone group (p = 0.011). There was a trend, although not statistically significant, for patients in the GM-CSF group to experience delayed progression of their retinitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical use of haematological growth factors in patients with human immunodeficiency virus (HIV-1) infection

HIV-infected patients commonly experience haematological disturbances including anemia, neutropenia or thrombocytopenia. Bone marrow failure may be caused by HIV itself, or by secondary involvement by opportunistic pathogens and malignancy. The need for multiple concomitant suppressive treatments may increase the risk of cytopenias. Strategy to reduce both anemia and neutropenia as well as to improve the haematological tolerance to myelotoxic agents have been developed by using haematological growth factors. So far, erythropoietin and granulocyte(macrophage) colony-stimulating factors have been successfully used in clinical trials including HIV-patients with either zidovudine-associated anemia or severe HIV or drug-induced neutropenia. However, according to the cost of these palliative approaches, there is a need for more reliable data showing that these growth factors could really have a major impact on the patient's compliance to therapy, reduction of hospitalization and infection rate and improvement of the overall survival.

Zidovudine. An update of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy

Zidovudine remains the mainstay in the treatment of patients infected with human immunodeficiency virus (HIV). The drug delays disease progression to acquired immunodeficiency syndrome (AIDS) and to AIDS-related complex (ARC), reduces opportunistic infections, and increases survival in patients with advanced HIV infection. There is evidence to suggest that zidovudine also delays disease progression in patients with mild symptomatic disease. Although one study has shown zidovudine to have no significant beneficial effects on survival or disease progression in patients with asymptomatic HIV infection, several other studies have shown zidovudine to delay disease progression in this patient group. Results from related ongoing studies are awaited with interest. Zidovudine reduces the incidence of AIDS dementia complex (ADC) and appears to prolong survival in these patients, and improves other neurological complications of HIV infection. The drug also appears to enhance the efficacy of interferon-alpha in patients with Kaposi's sarcoma. Although zidovudine is widely used as postexposure prophylaxis following accidental exposure to HIV, its efficacy in preventing seroconversion is unclear. Whether zidovudine prevents vertical transmission also remains to be determined. The overall efficacy of zidovudine in the treatment of children with HIV infection appears similar to that in adults despite more rapid disease progression in younger patients. Zidovudine-resistant isolates can emerge as early as after 2 months' therapy, and primary infection with zidovudine-resistant strains has been documented. Both zidovudine resistance and the syncytium-inducing HIV phenotype appear to be associated with poor clinical outcome. However, zidovudine resistance may revert on drug withdrawal or switching to an alternative therapy. Zidovudine-associated haematotoxicity may be dose-limiting. Nonhaematological adverse events associated with zidovudine therapy are generally mild and usually resolve spontaneously. Dosages of approximately 500 to 600 mg/day appear to be at least as effective as dosages of 1200 to 1500 mg/day and are better tolerated in patients with less advanced disease. However, optimal dosage are unclear. Despite beneficial effects, zidovudine monotherapy is not curative. There is evidence to suggest that the concomitant administration of zidovudine with didanosine or zalcitabine is effective in patients with HIV disease progression despite receiving zidovudine monotherapy, and there is some evidence that concomitant zidovudine plus didanosine therapy is more effective than alternating monotherapy. However, results from studies of combination therapy in asymptomatic patients, and from comparative combination therapy studies are awaited. Cotherapy with agents that augment haematopoiesis allows the continuation of therapeutic zidovudine dosages.(ABSTRACT TRUNCATED AT 400 WORDS)

Southwestern Internal Medicine Conference: clinical use of hematopoietic growth factors

The hematopoietic growth factors, granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF), have been cloned, produced in bacteria and yeast, and approved for clinical use in the treatment of neutropenia. Both factors stimulate the proliferation and maturation of neutrophil progenitors and enhance the effector functions of mature cells by interaction with specific receptors on the cell surface. Serum levels of G-CSF correlate inversely with the neutrophil count, suggesting that G-CSF may be the normal homeostatic regulator of the neutrophil count, while GM-CSF is generally undetectable in the serum and appears under normal physiologic conditions to act locally at inflammatory sites. Phase I and II clinical trials with these factors demonstrated minimal toxicity for G-CSF and mild to moderate dose-dependent toxicity for GM-CSF. Recent clinical trials, including double-blind, randomized studies, support a role for these growth factors in the treatment of chronic neutropenias, such as Kostmann's syndrome, acquired immune deficiency syndrome (AIDS), aplastic anemia, and myelodysplasia, as well as in acute neutropenias, such as cyclic neutropenia, chemotherapy-induced neutropenia, and bone marrow transplantation.

Kaposi's sarcoma. Epidemiology, pathogenesis, histology, clinical spectrum, staging criteria and therapy

The acquired immunodeficiency syndrome (AIDS) epidemic has had a profound impact on our understanding of Kaposi's sarcoma (KS). Epidemiologic features suggest a sexually transmitted cofactor in the pathogenesis of AIDS-associated KS (AIDS-KS), and several putative agents have received intense scrutiny. Cell culture studies suggest that the angiogenesis of AIDS-KS is stimulated by both human immunodeficiency virus proteins and growth factors that may be involved in the development and progression of AIDS-KS, thereby providing a rationale for new therapeutic interventions. The dermatologist is uniquely qualified to provide care for the majority of patients with KS, as many patients have cutaneous lesions amendable to local therapy (cryotherapy, intralesional therapy, simple excision). Patients requiring more aggressive local therapy (radiation therapy) or systemic therapies (interferon, chemotherapy) can be easily recognized. Standardized staging criteria provide assistance for determining appropriate local or systemic therapy and for evaluating and comparing responses to new therapies. This article reviews the epidemiology, pathogenesis, histologic features, clinical spectrum, staging criteria, and treatment of KS.

Therapeutic use of granulocyte-macrophage colony-stimulating factor (GM-CSF). A review of recent experience

Recombinant cytokines are now available for clinical use. Several colony-stimulating factors (CFS) have been identified which induce activation, proliferation and maturation of myeloid lineage cells. Recent therapeutic trials with granulocyte-macrophage colony-stimulating factors (GM-CSF) in association with chemotherapy, bone marrow transplantation and leukemia treatment are reviewed. GM-CSF as primary treatment for myelodysplasia and other types of bone marrow failure is also of interest. Colony-stimulating factor therapy in AIDS may be useful in order to reduce myelodepression caused by antiviral treatment and chemotherapy for associated malignancies like Kaposi's sarcoma. However, the effect of neutrophil count increase on infection is far from clear, and the real benefit of GM-CSF in cancer therapy has yet to be demonstrated.

In-vivo effect of interleukin 3 and erythropoietin, either alone or in combination, on the hematopoietic toxicity associated with zidovudine

We studied the effect of erythropoietin (EPO) and interleukin 3 (IL-3), either alone or in combination, on the hematopoietic toxicity associated with zidovudine in vivo, as determined by peripheral blood indices, and assay of hematopoietic progenitors, i.e. erythroid (CFU-E/BFU-E), myeloid (CFU-GM) and megakaryocyte (CFU-Meg) from bone marrow and spleen. Previous studies from this laboratory have established that dose escalation of zidovudine to normal mice induced a dose-dependent decrease in hematocrit, white blood cells and platelets with altered populations of marrow and splenic erythroid, myeloid and megakaryocyte progenitors. Daily administration of EPO (50 U/animal, i.p.) and/or IL-3 (5 U/animal, i.p.) was associated with altered peripheral blood indices and progenitor cells. In general, use of EPO and IL-3 alone reduced zidovudine-induced toxicity, notably in erythropoiesis; however, combination EPO/IL-3 was associated with enhanced toxicity with an observed rebound only with the use of < 2.5 mg/ml drug; 2.5 mg/ml drug in the presence of combination EPO/IL-3 accelerated zidovudine-erythroid toxicity. A similar response was noted with circulating platelets and megakaryocyte progenitors. Use of EPO or IL-3, either alone or in combination, failed to reverse zidovudine-induced neutropenia. These studies demonstrate that use of EPO or IL-3, either alone or in combination may serve as an effective adjuvant therapy to modulate the erythroid toxicity associated with lower doses of zidovudine; however, this cytokine therapy was ineffective modulating zidovudine-induced myelosuppression when used in vivo. A reversal in zidovudine-induced myeloid toxicity, therefore may require the use of a myelopoiesis inducing cytokine.

Colony-stimulating factors: a new step in clinical practice. Part I

Haematopoietic colony stimulating factors (CSFs) stimulate the proliferation, differentiation and functional activity of myelocytes. Since approval of the use of these factors in patients with chemotherapy-induced neutropenia, patients undergoing autologous bone marrow transplantation (BMT) and patients with delayed engraftment after BMT, several other potential clinical uses have been described. Current and potential future clinical applications of CSFs will be reviewed.

Antiviral therapy: current concepts and practices

Drugs capable of inhibiting viruses in vitro were described in the 1950s, but real progress was not made until the 1970s, when agents capable of inhibiting virus-specific enzymes were first identified. The last decade has seen rapid progress in both our understanding of antiviral therapy and the number of antiviral agents on the market. Amantadine and ribavirin are available for treatment of viral respiratory infections. Vidarabine, acyclovir, ganciclovir, and foscarnet are used for systemic treatment of herpesvirus infections, while ophthalmic preparations of idoxuridine, trifluorothymidine, and vidarabine are available for herpes keratitis. For treatment of human immunodeficiency virus infections, zidovudine and didanosine are used. Immunomodulators, such as interferons and colony-stimulating factors, and immunoglobulins are being used increasingly for viral illnesses. While resistance to antiviral drugs has been seen, especially among AIDS patients, it has not become widespread and is being intensely studied. Increasingly, combinations of agents are being used: to achieve synergistic inhibition of viruses, to delay or prevent resistance, and to decrease dosages of toxic drugs. New approaches, such as liposomes carrying antiviral drugs and computer-aided drug design, are exciting and promising prospects for the future.

The use of GM-CSF in AIDS

Hematopoietic growth factors may mitigate the cytopenias that frequently complicate HIV disease or its treatment. Clinical and in vitro studies have indicated the ability of granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF) or erythropoietin (EPO) to overcome the myelosuppression of HIV or many of the drug therapies used in the care of HIV-infected individuals. In addition, neutrophil or monocyte functional abnormalities observed in AIDS patients may be improved by the use of GM-CSF. Issues which may distinguish the use of hematopoietic growth factors in AIDS as compared with in other clinical settings include: 1) interaction of the growth factor with other cytokines which are aberrantly expressed, 2) direct effects of the growth factor on the replicative activity of HIV, and 3) potential interactions of the growth factor with other concurrently administered medications. This review focuses on the potential roles and limitations of growth factor use in AIDS and reviews the clinical studies using GM-CSF in HIV-infected individuals.

Cytokines in clinical cancer therapy

Cytokines have been of much interest in clinical cancer therapy research over the past decade. One important advance during the past year has been the clear demonstration, in large prospective randomized studies, that granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor reduce the neutropenia-related morbidity of cancer therapy.