IMMUNOPHARMACOLOGIC AGENTS. Dott.ssa Mariagrazia Grilli

Transcription

1 IMMUNOPHARMACOLOGIC AGENTS Dott.ssa Mariagrazia Grilli

2 IMMUNOPHARMACOLOGIC AGENTS: TWO CATEGORIES - those that suppress the immune system - those that stimulate the immune system

3 IMMUNE SYSTEM

4 hyper-active against self against foreign IMMUNOSUPPRESSIVE THERAPY

5 IMMUNOSTIMULANTS Overimmunosuppression hypo-active OPPORTUNISTIC INFECTION

6 IMMUNE RESPONSES: TWO MAJOR MECHANISMS 1. CELL-MEDIATED IMMUNITY 2. HUMORAL (ANTIBODY)-MEDIATED IMMUNITY Soluble factors (cytokines) have a vital role in Initiation and regulation of both immune responses

7 ACTIVE IMMUNIZATION 1. Activation of lymphocytes 2. Proliferation of lymphocytes 3. Differentiation of lymphocytes Differentiation Bacteria activation Plasma cell Macrophages Lymphocytes Proliferation Antibody

8 IMMUNE RESPONSE Bacteria Lysosomal Degradation Of proteins Loading Peptide Fragments on to Class II MHC Macrophages/ APC

9 ANTIGEN PRESENTATION MHC II CD4 APC T-Cell Peptide TCR

10 LYMPHOCYTE ACTIVATION AND HELP Th1 IL-2, IL-6,γ-IFN or T-Cell Th2 IL-4, IL-5, IL-10 B cell Activated T cells Proliferate and differentiate

11 IMMUNE RESPONSE Primary Response Secondary Response IgG Antibody levels IgG IgM

12 VIRUS INFECTED CELLS - CMI virus MHC-I TCR CD8 T-Cell Epithelial Cell

13 OVERALL SCHEME OF IMMUNE RESPONSE MHC Class I/peptides APCs CD8 T-cell IL-2 proliferation & differentiation CD8 cytolytic T-cells MHC Class II/peptides APCs IL-1 CD4 T-cell (helper T-cells) proliferation CD4 immune cell (delayed hypersensitivity) IL-1, -4,-5,-6 Protein antigen B-cell proliferation & differentiation Plasma cell antibody production

14 IMMUNOSUPPRESSIVE INTERVENTION

15 CLINICAL INDICATIONS FOR IMMUNOSUPPRESSANTS hyper-active against self against foreign 1. Prevention/reduction of rejection in organ transplantation 2. Prevention of GVHD (Graft Versus Host Disease) 3. Treatment of autoimmune diseases 4. Treatment of some other inflammatory diseases resistant to firstline therapy (eg glucocorticoids for asthma)

16 TRANSPLANTATION Different Species Autologous Xenogenic Allogenic

17 INDICATIONS FOR TRANSPLANT 1. ENDSTAGE ORGAN FAILURE KIDNEY PANCREAS HEART LUNG LIVER SMALL BOWEL solid organ 2. SYNGENEIC/ALLOGENEIC BONE MARROW TXPL 3. AUTOLOGOUS BONE MARROW TXPL

18 AUTOLOGOUS BONE MARROW TXPL

19 GRAFT REJECTION Hyperacute In minutes Acute 7 to 21 Days Chronic 3 Months

20 THE IDEAL IMMUNOSUPPRESSANT

21 CLASSES OF IMMUNOSUPPRESSANTS T cell blockers Glucocorticoids Cytotoxic Drugs Antibody reagents

22 CYCLOSPORIN-A Struttura: - undecapeptide ciclico liposolubile di origine fungina - nel 1976 Borel et al. descrivono i potenti effetti inibitori sull attivazione dei linfociti T, in assenza di tossicità sugli stessi e di attività antiproliferativa su altri tipi cellulari

23 USO CLINICO: CICLOSPORIN A DOSAGGIO: - prevenzione rigetto di allotrapianto rene, fegato, cuore ( + azatioprina e prednisone), polmone, pancreas - GVHD acuta e cronica - malattie autoimmuni (AR, MG, PSORIASI, UVEITI) (solo se divenute refrattarie ai farmaci convenzionali) OS/IV 15 mg/kg 4-24 h prima w dopo trapianto ridurre fino a 3-10 mg/kg/die EFFETTI COLLATERALI: nefrotossicità: dose-dipendente (att.ne alle interazioni con altri farmaci!) neurotossicità ipertensione irsutismo, iperplasia gengivale

24 FK506 (TACROLIMUS) - ORIGINE: fungina - STRUTTURA CHIMICA: non correlata alla CsA - ATTIVITÀ BIOLOGICA/MECCANISMO simili alla CsA - EFFETTI COLLATERALI: nefrotossicità neurotossicità disturbi GI iperglicemia sindrome linfoproliferativa infezioni - UTILIZZO TERAPEUTICO: ad oggi prevalentemente limitato a FK506 trapianto rene e fegato, in alternativa alla CsA (se troppo tossica o inefficace)

25 T- cell

26 MECHANISM OF ACTION OF CYCLOSPORIN IMMUNOPHILINS Cyclophilin (CsA) FKBP12 (FK-506) FKBPs (rapamycin)

27 SIROLIMUS: A NEW T-CELL BLOCKER SOURCE: fungal product MECHANISM OF ACTION: different than CsA and FK 506 (blocks mtor kinase) USE: prophylaxis of organ transplant rejection in combination with CsA and GC SIDE EFFECTS: hyperlipidemia, anemia, leukopenia, thrombocytopenia, fever, GI effects, hyper- or hypokalemia

28 CLASSES OF IMMUNOSUPPRESSANTS T cell blockers Glucocorticoids Cytotoxic Drugs Antibody reagents

29 STEROIDS SECRETED BY ADRENAL CORTEX ANDROGENS MINERALOCORTICOIDS GLUCOCORTICOIDS Precursor for synthesis - cholesterol ( Lipid lowering drugs )

30 STEROIDS Mineralocorticoids affect water and electrolyte (Na + /K + ) balance ALDOSTERONE Glucocorticoids affect carbohydrate and protein metabolism (stress response) HYDROCORTISONE (cortisol) immunosuppressive/anti-inflammatory activity (IN DOSES ABOVE NORMAL LEVELS)

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35 GLUCOCORTICOID-SENSITIVE SITES OF IMMUNE RESPONDING MHC Class I/peptides APCs GC CD8 T-cellT IL-2 proliferation & differentiation CD8 cytolytic T-cells X X GC MHC Class II/peptides APCs IL-1 X CD4 T-cellT (helper T-cells) T proliferation IL-1, -4, 4,-5, 5,-6 X CD4 immune cell (delayed hypersensitivity) Protein antigen B-cell proliferation & differentiation Plasma cell antibody production

36 USE OF GLUCOCORTICOIDS (as immunosuppressants/antiinflammatory drugs) - Autoimmune diseases Reumathoid Arthritis Dermatomyositis-Polimyositis Myastenia gravis (GC o GC + /Azathioprine/CsA) Colitis ulcerosa ( + sulfasalazina) - organ txpl (in association with other immunosuppressants) - allergic diseases (asthma; allergic drug reaction; dermatitis, eczema; psoriasis)

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38 Short acting Half-life GC MC AI activity activity activity Cortisol < 12 h Cortisone < 12 h Intermediate acting Prednisone h Prednisolone h Long acting Dexametasone > 36 h 10 < /30 Betametasone > 36 h 25 < /30

39 SIDE EFFECTS OF GLUCOCORTICOIDS Major side effects are common due to high doses necessary for immunesuppression increased risk of infections glucose intolerance fluid retention (Na retention, K depletion) weight gain osteoporosis hypertension decreased wound healing and ulcerations muscle wasting

40 CUSHING SYNDROME due to excess production/ administration of GC redistribution of body fat from extremities (ie. Arms and legs) to neck, face and abdomen from Pharmacology Rang et al

41 SIDE EFFECTS OF GLUCOCORTICOIDS - Growth suppression in children - Neuropsychiatric disturbances apathy, depression, irritability, insomnia, sometime psychosis - GC withdrawal syndrome fever, myalgias, arthralgas; malaise

42 USE OF GC IN IMMUNOSUPPRESSION (1) 1. Use with other immunosuppressants 2. Natural GC not used for their MC activity and low AI activity 3. Avoid long acting GC that can cause sustained suppression of the HPA axis 4. Most common long term regimen is intermediateacting GC (prednisone)

43 USE OF GC IN IMMUNOSUPPRESSION (2) 5. Most common long-term regimen is intermediateacting GC in divided doses (prednisone t.i.d.) 6. Alternate day therapy should be considered for chronic therapy, especially for inflammatory disorders (minimizes problems associated with feedback suppression) E.g. : single dose of GC on alternate mornings (8 AM) in an amount equivalent to the total dose ordinarily given over a 48 h period. - mimics natural circadian rhythm of cortisol (cortisol peaks around 8 AM so HP-axis normally suppressed) - shorter plasma half-life of GC allows HP-axis to undergo circadian rhythm while pharmacodynamic effect will last about 36 h

44 USE OF GC IN IMMUNOSUPPRESSION (3) Patients on long-term therapy need dietary changes high in protein and potassium low sodium and overall calories monitoring of serum calcium, glucose, and blood pressure antacids for gastric problems if needed Minimize GC-induced osteopenia (Exercise; high Calcium intake, consider vitamin D, annual BMD) Termination of treatment must be gradual atrophy of HPA axis, can t respond to stress

45 HPA AXIS - ADRENAL HYPOTHALAMUS CRF ANTERIOR PITUITARY ACTH CORTEX (ADRENAL GLAND) - STEROIDS CRF = corticotrophin-releasing factor ACTH = adrenocorticotropic hormone /corticotrophin

46 REPRESENTATIVE GLUCOCORTICOIDS Oral (Short-, Intermediate- and Long-acting) cortisol(-s), cortisone(-s), corticosterone (-S) methylprednisolone(-s) prednisolone(-i), triamcinolone(-i) dexamethasone(-l), betamethasone(-l) Inhalation beclomethasone, flunisolide, fluticasone Topical (amcinonide), ophthalmic (medrysone), intranasal (mometasone) and injectable versions also available

47 CLASSES OF IMMUNOSUPPRESSANTS T cell blockers Glucocorticoids Cytotoxic Drugs Antibody reagents

48 Rationale CYTOTOXIC DRUGS AS IMMUNOSUPPRESSANTS Antineoplastic drugs will also prevent clonal expansion of both T- and B- cells nonspecifically via interfering with DNA/RNA synthesis and function Drugs (Mechanism) Azathioprine (prodrug of nucleotide anti-metabolite) Cyclophosphamide (DNA alkylating agent) Methotrexate (inhibits dihydrofolate reductase) Mycophenolate mofetil (becomes MPA; inhibits IMP dehydrogenase)

49 USES OF CYTOTOXIC DRUGS Azathioprine: used in combination with other immunosuppressants (CsA and/or prednisone) for organ transplants (kidney, liver) and in severe rheumatoid arthritis (refractory to therapy) Cyclophosphamide: used in BMT Methotrexate: GVHD prophilaxis; rheumatoid arthritis, psoriasis (+ CsA) Mycophenolate mofetil: used in combination with CsA and prednisone for kidney txpl

50 SIDE EFFECTS OF CYTOTOXIC DRUGS - bone marrow suppression --- risk for infections - infertility - GI toxicity - increased risk of cancer - lung and liver fibrosis (MTX) - aseptic chronic pneumonia (MTX)

51 THE IDEAL IMMUNOSUPPRESSANT.no such drug is currently available

52 COMBINING DIFFERENT CLASSES OF IMMUNOSUPPRESSANTS - to minimise side effects and reduce the doses of individual drugs - synergise therapeutic effects - especially in organ transplantation eg. maintenance immunosuppressive therapy in a renal txpl patient: Prednisone 5 mg daily PO Azathioprine 100 mg daily PO Cyclosporin 75 mg bd PO

53 CLASSES OF IMMUNOSUPPRESSANTS T cell blockers Glucocorticoids Cytotoxic Drugs Antibody reagents

54 IMMUNOSUPPRESSIVE ANTIBODIES Ag Polyclonal antibodies Monoclonal antibody

55 IMMUNOSUPPRESSIVE ANTIBODIES Rh(D) immune globulin Antithymocyte antibodies Anti-TNFα antibodies

56 ERYTHROBLASTOSIS FETALIS Rh(D) negative Mother Father Rh (D) Positive Baby Rh(D) positive Antibody to RhD+ erythrocytes First pregnancy OK. But sensitizes the mother Second pregnancy - high risk. Antibodies given < 72 hrs after delivery to prevent maternal sensitization

57 ANTITHYMOCYTES ANTIBODIES Lymphocyte/thymocyte immune globulins (Atgam, thymoglobulin) lytic to human thymic lymphocytes; blocks T-cell responding Anti-CD3 monoclonal antibody (OKT3, muromonab-cd3) binds CD3, blocks antigen binding; depletes T-cells Anti-Tac, Anti-CD25(basiliximab, daclizumab) monoclonal antibodies (anti-cd25 are humanized) bind IL-2 receptors on activated T-cells causing their inactivation

58 OKT3 Monoclonal antibody against T-cell receptor Provokes T-cells apoptosis Used in severe graft rejection Profound immune suppression and infection risk

59 ANTI-TNFα ANTIBODIES Three approved drugs : infliximab 1, etanercept, adalimumab Approved for 1. treatment of refractory Rheumatoid Arthritis used alone or 1 with other DMARDs (e.g. methotrexate) given S.C. (infliximab follow-up I.V.) 2. Crohn Disease Adverse effects exacerbation of heart failure (infliximab and etanercept) increased infections, esp. tuberculosis with adalimumab (reactivation of latent, test first) exacerbations/development of demylelinating diseases

60 GENERAL PRINCIPLES REGARDING IMMUNOSTIMULATION Stimulating cellular and/or humoral immunity should benefit people with immune deficiencies Degree of stimulation relatively small

61 CLINICAL USE OF IMMUNOSTIMULANTS - CANCER - VIRAL INFECTIONS - CHRONIC DISEASE WITH IMMUNE PATHOGENESIS - CHEMOTHERAPY - BMT

62 CLASSES OF IMMUNOSTIMULANTS (Biological Response Modifiers, BRM) Cytokines Bacteria-derived products Synthetic Drugs Intravenuos immune globulin Vaccines

63 CYTOKINES AS IMMUNOSTIMULANTS Interferons: 3 types; α, β, γ All inhibit viral replication and modulate immune responses Low doses are immunostimulatory (especially IFN-γ activating NK cells, macrophages and cytotoxic T-cells) bind IFN receptors, activate genes

64 INTERFERONS INF-α INF-β INF-γ MAJOR PRODUCER CELLS Leukocytes/ macrophages Fibroblasts/ epithelial cells T cells/ NK cells MAJOR INDUCERS virus Virus, LPS Antigens, mitogens BIOLOGICAL PROPERTIES 1.Antiviral activity Yes Yes 0-100X less than INF- α/ β 2. Immunomodulatory activity X less than INF- γ X less than INF- γ Yes 3. Cytotoxic activity yes yes Yes 4. Cytostatic activity yes yes

65 disease CLINICAL USE OF INTERFERONS Interferon-alfa (2a/2b) ( rhifnα) USE: approved for treatment of hairy cell leukemia, AIDS-related Kaposi s sarcoma, human papillomavirus and hepatitis B and >> C infections pegylated -alfa-2b as monotherapy (1/wk) for HCV Interferon-β-1a/1b (analogs of IFN-β) USE: may reduce number and severity of attacks in relapsing-remitting multiple sclerosis Interferon-γ-1b USE: approved for prevention of infections in chronic granulomatous

66 TOXICITY OF INTERFERONS Flu-like syndrome fever Fatigue Headaches Myalgias GI disturbances Cardiovascular disturbances

67 INTERLEUKIN-2 Major T-cell growth factor Binds to IL-2 receptor on immune cells Induces proliferation and differentiation of helper T-cells and cytotoxic T-cells Elevates serum IL-1, TNF-α, IFNγ levels

68 USES OF INTERLEUKIN-2 rhil-2 (human recombinant IL-2; aldesleukin) approved to treat metastatic renal cancer and melanoma highly toxic capillary leak syndrome associated with edema, reduced organ perfusion and hypotension cardiac arrhythmias, myocardial infarction, GI bleeding, changes in mental status increase incidence of infections

69 COLONY STIMULATING FACTORS (G-CSF/GM-CSF) 1. CHEMOTHERAPY-INDUCED NEUTROPENIA Rationale: neutrophils are the shortest-lived blood cells and both G- /GM-CSF stimulate neutrophil production Advantages: - reduce infections secondary to the toxic therapy - allow for dosage escalation of chemo/radiation; kill more cancer 2. BONE MARROW TRANSPLANTATION Rationale: several weeks (2-4) after BMT, the transplanted marrow must graft and proliferate; during this period the patient is extremely susceptible to infections Advantages: accelerate recovery of PBN counts; reduce infections; shorten hospitalization

70 SIDE EFFECTS OF G-CSF/GM-CSF Bone pain primary adverse effect of short-term treatment Splenomegaly and abnormal urate levels may occur Fluid accumulation most bothersome advers effect of short-term GM-CSF

71 BACTERIAL-DERIVED AGENTS - Only Bacille Calmette-Guerin (BCG) licensed for use in USA; several other in use world-wide - BCG is an attenuated live strain of M. bovis 1. acts in part by stimulating TNF-α release from macrophages 2. approved for intravescical therapy of superficial bladder cancer - Side effects: Hypersensitivity, shock, chills, fever, immune complex disease

72 LEVAMISOLE-HCL - Can potentiate stimulation of lymphocytes, granulocytes and macrophages by various factors SYNTHETIC AGENTS AS IMMUNOSTIMULANTS - Approved for use with 5-flurouracil 5 in resected patients with Dukes C colon cancer

73 TYPES OF IMMUNOTHERAPIES Active immunization Vaccination Longer duration of protection Delayed onset Passive immunization Preformed antibodies (anti-tetanus serum) Immediate onset Shorter duration of protection

74 VACCINES I Bubonic Plague Diphtheria, Tetanus, Whooping cough Meningitis Tuberculosis Typhoid Pneumonia Inactivated Yersinia Pestis DPT adsorbed toxoids Meningococcal polysaccharide Attenuated Mycobacterium bovis Killed Salmonella typhosa Pneumococcal capsule

75 VACCINES II Polio Rubella Mumps Yellow fever Influenza Small pox Rabies hepatitis Attenuated virus Attenuated virus Attenuated virus Attenuated virus Inactivated virus Vaccinia virus Killed, fixed virus Purified coat protein

76 INTRAVENOUS IMMUNE GLOBULINS (PASSIVE IMMUNIZATION) IV IGs are pooled plasma from donors they contain no IgM, variable IgA, normal IgG subclasses Used as replacement therapy in primary immune deficiency diseases All except Gammagard are contraindicated in IgA deficiency Specific preparations also available hepatitis B, botulism, diptheria, tetanus, rabies