Interleukin-2 for the treatment of HIV infection

Clinicians have used combination antiretroviral therapy to treat HIV infection since 1996, and these drugs can produce a significant reduction in viral load as well as mitigate immune deficiency caused by HIV. For many patients, however, combination therapy fails to provide adequate immune system restoration, an important part of HIV infection management. The immune-based therapy most studied for treatment of HIV is interleukin-2 (IL-2), a cytokine licensed for the treatment of renal cell carcinoma. Chiron Corporation manufactures recombinant IL-2 under the brand name Proleukin. Characteristics and biological activity of IL-2 are detailed, along with the rationale for including the drug in anti-HIV treatments. Data from clinical trials are presented. Practical steps to diminishing toxicity of IL-2, and the controversy surrounding its approval by the U.S. Food and Drug Administration (FDA) are detailed.     

Aldesleukin (Recombinant Interleukin-2)

Aldesleukin [recombinant interleukin-2 (IL-2)] is a biological response modifier which, like endogenous IL-2, has a range of immunomodulatory properties. Although aldesleukin is currently approved only for treatment of renal cell carcinoma, it has been widely used in patients with metastatic melanoma and has been assessed in numerous noncomparative trials in this indication. Durable complete responses have been reported in a small proportion of patients with good performance status who received immunotherapy or chemoimmunotherapy involving aldesleukin in several clinical trials. Overall median survival times of about 10 or 11 months are typical. Combination chemoimmunotherapy involving aldesleukin has produced relatively high response rates (up to 56%), but these are not predictive of increased survival time. Aldesleukin has not been directly compared with standard chemotherapy in randomised studies. The use of continuous intravenous infusion and subcutaneous administration of aldesleukin, together with improved patient selection, has successfully reduced the severity of adverse events produced by the drug (the original intravenous bolus regimen is particularly toxic and often necessitates admission to an intensive care unit). However, the risk/benefit profile of aldesleukin in the treatment of melanoma requires further study, particularly after subcutaneous administration. Thus, aldesleukin has shown modest efficacy in the treatment of metastatic melanoma. Although aldesleukin-containing regimens have produced promising results in many noncomparative trials, their clinical value in comparison with standard chemotherapy remains to be determined in phase III studies. Until results from such trials are available, clinicians will need to carefully balance the potential benefits of the drug against the risks and likely quality-of-life implications associated with its toxicity in each patient. Current investigations centre on the use of aldesleukin as part of complex biochemotherapy regimens, and results from these trials are awaited with interest.     

Aldesleukin (Recombinant Interleukin-2)

Aldesleukin (recombinant interleukin-2), like endogenous interleukin-2 (IL-2), has a variety of immunomodulatory properties. It is currently approved for intravenous use in patients with renal cell carcinoma, in whom it appears to have an indirect antitumour effect mediated by increased activity of the host's immune system. A large number of clinical trials (typically noncomparative) have established the efficacy of aldesleukin monotherapy in patients with renal cell carcinoma. Response rates of 13 to 20% achieved after intravenous administration and 18 to 31% after subcutaneous administration are greater than those previously reported ( approximately 10%) for other chemo- and immunotherapeutic agents. Furthermore, many patients who were previously refractory to treatment have achieved stable disease status or better after aldesleukin therapy. Median survival times of at least 37 months have been achieved, and perhaps more encouraging is an isolated report of a 5-year actuarial survival rate of 23%. Bolus intravenous administration of aldesleukin was associated with frequent, and occasionally life-threatening, adverse events. Hypotension and renal, pulmonary and cardiac complications were primarily manifestations of increased vascular permeability. Symptoms were generally manageable with treatment interruption and standard pharmaceutical and/or clinical intervention, although some treatment-related deaths were reported. The severity of adverse events was reduced with continuous infusion of the agent and more substantially so when aldesleukin was administered subcutaneously. In conclusion, despite a lack of comparative and phase III trials, aldesleukin therapy appears to result in a slightly better response rate than those previously reported with other antineoplastic therapies in this difficult-to-treat patient population. Retrospective data indicate that survival duration may be moderately increased by aldesleukin, but further prospective comparative data are required before this may be proven. In view of the poor prognosis associated with renal cell carcinoma, efficacy data from clinical trials evaluating aldesleukin, together with the potential for reducing adverse events by changing its route of administration, suggest the drug may be a worthwhile therapy for patients with this disease.     

Anti-Gonadotropin Releasing Hormone Vaccines and Their Potential Use in the Treatment of Hormone-Responsive Cancers

Gonadotropin-releasing hormone (GnRH) and its analogues have been used clinically to treat a range of hormone-dependent conditions. It is often necessary for large, toxic and expensive drug doses to be administered. Improvements in drug delivery have necessitated new developments in formulation, but these in turn can induce new adverse effects. Immunological neutralisation of GnRH has been examined as a less toxic and cheaper replacement therapy, and has been studied closely in different animal species. However, only a few clinical trials have been carried out with respect to hormone-dependent cancers. Based on clinical trials of the free peptide drug in cancer patients, it would appear that there is an increasing trend towards using GnRH and its analogues in adjuvant therapy and that antibody-based GnRH neutralisation will have a role in this treatment regimen.     

Is There a Higher Risk of CNS Adverse Events for PI Monotherapy Versus Triple Therapy? A Review of Results From Randomized Clinical Trials

Background: Protease inhibitor (PI) monotherapy for treatment could avoid the adverse events, drug resistance, and additional costs associated with other antiretrovirals that are normally used, particularly the nucleoside analogues. PI monotherapy has mainly been compared with standard triple therapy in randomized clinical trials of patients who have HIV RNA suppression at screening and no history of virological failure. Methods: This review included 11 randomized clinical trials of darunavir/ritonavir (DRV/r) or lopinavir/ritonavir (LPV/r) monotherapy versus triple therapy in 1,267 patients with HIV RNA suppression at baseline who were studied between 48 and 144 weeks. Results: There was no clear difference in the risk of central nervous system (CNS) adverse events between PI monotherapy (either DRV/r or LPV/r) and standard triple drug treatment. There were 2 clinical trials – MONOI (DRV/r) and MOST (LPV/r) – that showed CNS symptoms and detectable HIV RNA levels in the cerebrospinal fluid in a small number of individuals taking PI monotherapy. Conclusions: There was no consistent evidence from the randomized trials currently available for an additional risk of HIV CNS disease during monotherapy with either LPV/r or DRV/r versus standard triple drug therapy. However, the information on CNS adverse events has not been reported using standardized definitions in the studies. In addition, few randomized studies included detailed analysis of neurocognitive function or detection of HIV RNA in the cerebrospinal fluid.     

Canakinumab: a human anti-IL-1β monoclonal antibody for the treatment of cryopyrin-associated periodic syndromes

The cryopyrin-associated periodic syndromes (CAPS) are a group of rare inherited inflammatory diseases associated with overproduction of IL-1β. Canakinumab, developed by Novartis AG (Basel, Switzerland), is an intravenously or subcutaneously administered, fully human monoclonal antibody that neutralizes the bioactivity of human IL-1β. Canakinumab has promising clinical safety and pharmacokinetic properties, and has demonstrated potential for the treatment of CAPS. Canakinumab was recently granted EU orphan drug status for systemic-onset juvenile idiopathic arthritis, and early clinical trials have established that administration of canakinumab every 2 weeks is both safe and effective. Subcutaneous canakinumab (approved formulation) offers some advantages over the existing IL-1β-blocking treatment, anakinra, which must be injected daily and is often not well tolerated by patients. The long-term safety of all targeted anti-IL-1 therapies in CAPS remains an unanswered question owing to the relatively short clinical experience with these agents; as canakinumab produces sustained IL-1 suppression, vigilance is necessary to diagnose the development of adverse events, especially any associated infections.     

Canakinumab: a human anti-IL-1β monoclonal antibody for the treatment of cryopyrin-associated periodic syndromes

The cryopyrin-associated periodic syndromes (CAPS) are a group of rare inherited inflammatory diseases associated with overproduction of IL-1β. Canakinumab, developed by Novartis AG (Basel, Switzerland), is an intravenously or subcutaneously administered, fully human monoclonal antibody that neutralizes the bioactivity of human IL-1β. Canakinumab has promising clinical safety and pharmacokinetic properties, and has demonstrated potential for the treatment of CAPS. Canakinumab was recently granted EU orphan drug status for systemic-onset juvenile idiopathic arthritis, and early clinical trials have established that administration of canakinumab every 2 weeks is both safe and effective. Subcutaneous canakinumab (approved formulation) offers some advantages over the existing IL-1β-blocking treatment, anakinra, which must be injected daily and is often not well tolerated by patients. The long-term safety of all targeted anti-IL-1 therapies in CAPS remains an unanswered question owing to the relatively short clinical experience with these agents; as canakinumab produces sustained IL-1 suppression, vigilance is necessary to diagnose the development of adverse events, especially any associated infections.     

Oral tolerance: therapeutic implications for autoimmune diseases

Oral tolerance is classically defined as the suppression of immune responses to antigens (Ag) that have been administered previously by the oral route. Multiple mechanisms of tolerance are induced by oral Ag. Low doses favor active suppression, whereas higher doses favor clonal anergy/deletion. Oral Ag induces Th2 (IL-4/IL-10) and Th3 (TGF-beta) regulatory T cells (Tregs) plus CD4+CD25+ regulatory cells and LAP+T cells. Induction of oral tolerance is enhanced by IL-4, IL-10, anti-IL-12, TGF-beta, cholera toxin B subunit (CTB), Flt-3 ligand, anti-CD40 ligand and continuous feeding of Ag. In addition to oral tolerance, nasal tolerance has also been shown to be effective in suppressing inflammatory conditions with the advantage of a lower dose requirement. Oral and nasal tolerance suppress several animal models of autoimmune diseases including experimental allergic encephalomyelitis (EAE), uveitis, thyroiditis, myasthenia, arthritis and diabetes in the nonobese diabetic (NOD) mouse, plus non-autoimmune diseases such as asthma, atherosclerosis, colitis and stroke. Oral tolerance has been tested in human autoimmune diseases including MS, arthritis, uveitis and diabetes and in allergy, contact sensitivity to DNCB, nickel allergy. Positive results have been observed in phase II trials and new trials for arthritis, MS and diabetes are underway. Mucosal tolerance is an attractive approach for treatment of autoimmune and inflammatory diseases because of lack of toxicity, ease of administration over time and Ag-specific mechanism of action. The successful application of oral tolerance for the treatment of human diseases will depend on dose, developing immune markers to assess immunologic effects, route (nasal versus oral), formulation, mucosal adjuvants, combination therapy and early therapy.     

Meta-analysis: silymarin and its combination therapy for the treatment of chronic hepatitis B

Silymarin is used by many patients with chronic hepatitis B, but its efficacy remains unknown. The aim of this investigation was to conduct a meta-analysis to determine the efficacy and safety of silymarin and its combination therapy for the treatment of chronic hepatitis B. We searched Chinese and English reports from January 1966 to December 2011, using 12 databases. Two reviewers independently screened all reports to identify randomized placebo-controlled trials that evaluated silymarin and its combination therapy for the treatment of chronic hepatitis B. Twelve trials satisfied the eligibility criteria for this meta-analysis. Silymarin was equivalent to antiviral drug or protection liver drugs in serum transaminases, viral load and hepatic fibrosis markers. But silymarin combined with antiviral drug or antiviral drug and protection liver drugs significantly reduced the level of serum transaminases, hepatic fibrosis markers and serum TGF-β1, TNF-α, IL-6 versus antiviral drug or protection liver drugs. Silymarin combined with protection liver drugs significantly reduced the level of serum transaminases, TBIL, hepatic fibrosis markers and was equivalent to protection liver drugs in the normalisation rates of serum transaminases, TBIL, but protection liver drugs significantly increased the improvement rates of hepatic fibrosis markers. Silymarin combined with antiviral drug or antiviral drug and protection liver drugs may have potential therapeutic value. Treatment with silymarin appears to be safe and well tolerated. The data are too limited to exclude a substantial benefit or harm of silymarin and its combination therapy on serum transaminases, and also to support recommending this herbal compound for the treatment of chronic hepatitis B.     

MDA-7/IL-24-based cancer gene therapy: translation from the laboratory to the clinic

Despite recent advances in treatment strategies, the overall 5-year survival rate for patients with common epithelial cancers is poor largely because of the difficulty in treating metastatic cancers. Therefore, therapeutic agents are urgently needed that can effectively inhibit both primary epithelial tumors and their metastases. One such agent that has shown promise in preclinical studies is the tumor suppressor/cytokine, melanoma differentiation associated gene-7 also known as interleukin-24 (mda-7/IL-24). Preclinical studies from our and other laboratories have shown that overexpression of MDA-7/IL-24 causes a strong tumor- suppressive effect in many human cancer cells but spares normal cells. This gene therapy also enhances the tumor-suppressive activity of radiotherapy and chemotherapy. Secreted MDA-7 protein that is glycosylated also has been shown to have potent antiangiogenic activity both in vitro and in vivo. Studies examining the immune properties of mda-7 have shown that MDA-7/IL-24 unlike the related IL-10, functions as a Th1 cytokine. Recently, an MDA-7 protein-mediated "bystander effect" on tumor cells has been documented. Building on these findings we successfully completed a Phase I clinical trial of adenovirus-based mda-7 cancer therapy that confirmed the safety of this gene therapy. Phase II trials evaluating the efficacy of mda-7-based gene therapy are warranted. The outcome of such ongoing mda-7-based gene therapy trials will allow us to better understand this therapy's clinical utility.     

Cells for sale

Some clinicians are claiming that IL-2 (interleukin-2) can quadruple T-cells, and is effective in rebuilding HIV-impaired immune systems. However, IL-2 also increases HIV replication. The increase can potentially be offset by combination therapy with protease inhibitors, but other concerns linger over IL-2's use in HIV treatment. It has minimal or detrimental effects on patients with T-cell counts below 200, the group most in need of an immune system boost. Insurance companies will generally not cover the treatment, and there are several cases of physicians charging exorbitant prices for the treatment. Patients taking IL-2 also suffer severe side effects, including nausea, aches, and flu-like symptoms. Drug trials are currently underway to test the effectiveness of IL-2.     

Advances in Liver Transplantation: where are we in the pursuit of transplantation tolerance?

Liver transplantation is the ultimate treatment option for end-stage liver disease. Breakthroughs in surgical practice and immunosuppression have seen considerable advancements in survival after transplantation. However, the intricate management of immunosuppressive regimens, balancing desired immunological quiescence while minimizing toxicity has proven challenging. Diminishing improvements in long-term morbidity and mortality have been inextricably linked with the protracted use of these medications. As such, there is now enormous interest to devise protocols that will allow us to minimize or completely withdraw immunosuppressants after transplantation. Immunosuppression withdrawal trials have proved the reality of tolerance following liver transplantation, however, without intervention will only occur after several years at the risk of potential cumulative immunosuppression-related morbidity. Focus has now been directed at accelerating this phenomenon through tolerance-inducing strategies. In this regard, efforts have seen the use of regulatory cell immunotherapy. Here we focus particularly on regulatory T cells, discussing preclinical data that propagated several clinical trials of adoptive cell therapy in liver transplantation. Furthermore, we describe efforts to further optimize the specificity and survival of regulatory cell therapy guided by concurrent immunomonitoring studies and the development of novel technologies including chimeric antigen receptors and co-administration of low-dose IL-2.     

Adoptive cell therapy with autologous tumor infiltrating lymphocytes and low-dose Interleukin-2 in metastatic melanoma patients

ABSTRACT: BACKGROUND: Adoptive cell therapy may be based on isolation of tumor-specific T cells, e.g. autologous tumor infiltrating lymphocytes (TIL), in vitro activation and expansion and the reinfusion of these cells into patients upon chemotherapy induced lymphodepletion. Together with high-dose interleukin (IL)-2 this treatment has been given to patients with advanced malignant melanoma and impressive response rates but also significant IL-2 associated toxicity have been observed. Here we present data from a feasibility study at a Danish Translational Research Center using TIL adoptive transfer in combination with low-dose subcutaneous IL-2 injections. METHODS: This is a pilot trial (Clinical trials.gov identifier: NCT00937625) including patients with metastatic melanoma, PS [LESS-THAN OR EQUAL TO]1, age <70, measurable and progressive disease and no involvement of the central nervous system. Six patients were treated with lymphodepleting chemotherapy, TIL infusion, and 14 days of subcutaneous low-dose IL-2 injections, 2 MIU/day. RESULTS: Low-dose IL-2 considerably decreased the treatment related toxicity with no grade 3--4 IL-2 related adverse events. Objective clinical responses were seen in 2 of 6 treated patients with ongoing complete responses (30+ and 10+ months), 2 patients had stable disease (4 and 5 months) and 2 patients progressed shortly after treatment. Tumor-reactivity of the infused cells and peripheral lymphocytes before and after therapy were analyzed. Absolute number of tumor specific T cells in the infusion product tended to correlate with clinical response and also, an induction of peripheral tumor reactive T cells was observed for 1 patient in complete remission. CONCLUSION: Complete and durable responses were induced after treatment with adoptive cell therapy in combination with low-dose IL-2 which significantly decreased toxicity of this therapy.     

The complex role of interleukin-10 in autoimmunity

Interleukin-10 (IL-10) is a cytokine that has been tested in different clinical trials based on its ability to down regulate T helper 1-type responses, namely IFN-gamma secretion and activation of monocytes/macrophages. There is also evidence in different animal models, that IL-10 could be useful in controlling Th2-mediated inflammatory processes. However, IL-10 also displays immunostimulatory properties especially on B cells and activated CD8(+)T cells. These seemingly divergent effects may explain the apparent lack of activity or adverse effects observed after IL-10 treatment in several animal models or clinical trials. Nevertheless, the ability of IL-10 to induce the differentiation of a subset of regulatory CD4(+)T cells (Tr1) and the importance of IL-10 for the in vivo function of regulatory T cells tends to support the view of IL-10 as a crucial cytokine in the control of immune responses. In different in vivo models, these cells were shown to inhibit Th1 and Th2-type inflammatory responses through the secretion of IL-10. These Tr1 cells may thus be used in specific cellular therapy in order to deliver IL-10 precisely at the site of inflammation.     

Severe asthma: advances in current management and future therapy

Effective treatment of severe asthma is a major unmet need because patients' symptoms are not controlled on maximum treatment with inhaled therapy. Asthma symptoms can be poorly controlled because of poor adherence to controller therapy, and this might be addressed by using combination inhalers that contain a corticosteroid and long-acting β(2)-agonist as reliever therapy in addition to maintenance treatment. New bronchodilators with a longer duration of action are in development, and recent studies have demonstrated the benefit of a long-acting anticholinergic bronchodilator in addition to β(2)-agonists in patients with severe asthma. Anti-IgE therapy is beneficial in selected patients with severe asthma. Several new blockers of specific mediators, including prostaglandin D(2), IL-5, IL-9, and IL-13, are also in clinical trials and might benefit patients with subtypes of severe asthma. Several broad-spectrum anti-inflammatory therapies that target neutrophilic inflammation are in clinical development for the treatment of severe asthma, but adverse effects after oral administration might necessitate inhaled delivery. Macrolides might benefit some patients with infection by atypical bacteria, but recent results are not encouraging, although there could be an effect in patients with predominant neutrophilic asthma. Corticosteroid resistance is a major problem in patients with severe asthma, and several molecular mechanisms have been described that might lead to novel therapeutic approaches, including drugs that could reverse this resistance, such as theophylline and nortriptyline. In selected patients with severe asthma, bronchial thermoplasty might be beneficial, but thus far, clinical studies have not been encouraging. Finally, several subtypes of severe asthma are now recognized, and in the future, it will be necessary to find biomarkers that predict responses to specific forms of therapy.     

Biological Agents in Rheumatoid Arthritis

Rheumatoid arthritis is a chronic inflammatory disease. Established treatment is limited because of the clinical response or the induction of adverse effects. New biological agents evaluated for treatment of rheumatoid arthritis have shown varied clinical success. These agents target cytokines such as tumour necrosis factor-alpha (TNFalpha), interleukin (IL)-1 or IL-6, or cell surface molecules such as CD4, CD5, CD7, IL-2 receptor, CDw52 or CD54. Amongst these new drugs, only a few have shown clinical effectiveness in double-blind placebo-controlled trials. These include the primatised nondepleting anti-CD4 monoclonal antibody (mAb) CE9.1 (keliximab), the TNFalpha-blocking mAbs cA2 (infliximab) and CDP-571, the human recombinant soluble TNFalpha receptors p55 (lenercept) and p80, as well as the human recombinant IL-1 receptor antagonist protein, anakinra. Thus, only these agents qualify for evaluation of combination treatment in rheumatoid arthritis. Rationales for combination therapy include: combining drugs with different sites of action to increase efficacy or with different toxicities to minimise risk; combining drugs with different kinetics, thus improving clinical activity; using a combination of drugs for the prevention of tachyphylaxis; or using a second drug which helps to prevent or delay the development of resistance to the first one. In addition, combination therapy could help to prevent or minimise adverse effects caused by treatment with biological agents. Based on knowledge from trials with biological agents, and on the different properties attributed to the established disease-modifying antirheumatic drugs (DMARDs) in ex vivo and in vitro studies, we propose evaluation of the following combination regimens involving biological agents. First, biological agents targeting TNFalpha (such as the mAbs cA2 or CDP-571, or the TNFalpha receptor p55-IgG1 fusion protein) given as a single infusion for rapid clinical response could be followed by continuation treatment with methotrexate, possibly combined with chloroquine, azathioprine or cyclosporin. Combination of specific anti-TNFalpha strategies with sulfasalazine should be avoided because of the induction of double-stranded DNA antibodies seen after TNFalpha blockade in vivo and reports on a systemic lupus erythematosus-like syndrome as an adverse effect during treatment with biological agents directed against TNFalpha or with sulfasalazine. Alternatively, continuous inhibition of TNFalpha or IL-1 with TNFalpha receptor p80-IgG1 fusion protein or IL-1 receptor antagonist, respectively, could be combined with methotrexate, with the disadvantage of a slower initial improvement of clinical symptoms. Combination regimens with the primatised CD4 mAb could include methotrexate as concomitant medication, with chloroquine or sulfasalazine as additional medication. Importantly, combination of different biological agents might induce more severe adverse effects than seen with monotherapy. Thus, protocols involving combinations of biological agents with established DMARDs promise better acceptance than combinations of 2 new and as yet unestablished drugs with possibly synergistic adverse effects because of their antigenic properties.     

Anakinra

Anakinra (Kineret) is the first biologic drug that has been developed specifically as an interleukin (IL)-1 receptor antagonist (Ra) and is derived from an endogenous IL-1Ra. The drug blocks the activity of IL-1 in synovial joints, reducing the inflammatory and joint destructive processes associated with rheumatoid arthritis (RA). In randomized, placebo-controlled trials of up to 52 weeks' duration, anakinra has shown efficacy both as monotherapy and in combination with other disease-modifying antirheumatic drugs (DMARDs) in adults with RA. It is subcutaneously administered and is generally well tolerated. Anakinra offers a useful addition to the range of drugs available for the treatment of RA.     

Development status of miltefosine as first oral drug in visceral and cutaneous leishmaniasis

An oral treatment for visceral and cutaneous leishmaniasis has been searched for over the last decades. An oral drug would facilitate treatment and lower costs. Oral miltefosine (Zentaris/ASTA Medica AG, Germany), an alkylphosphocholine, is under clinical development for treatment of leishmaniasis. Phase I, II and III clinical trials have been performed in visceral leishmaniasis in India; the overall response rate with 100 mg/day over 4 weeks is 96%. A first clinical trial in New World cutaneous leishmaniasis has shown a final cure rate of 94% at a dose of 150 mg/day over 3 or 4 weeks. Side effects are mainly gastrointestinal (vomiting, diarrhoea). Furthermore, transient elevation of transaminases or urea/creatinine has been observed. The clinical results suggest that miltefosine is the first oral therapy that is effective and safe in visceral and cutaneous leishmaniasis.