Monoclonal antibodies

A presentation on monoclonal antibodies

1. MONOCLONAL ANTIBODIES Presentation by Devi Pravallika . K

2. HISTORY Emil von Behring  and Kitasato Shibasaburo discovered in 1890 that diphtheria and tetanus toxins were neutralized in the bloodstream of animals by substances they called  antitoxins , which were specific for the respective toxin.  Behring received the first Nobel Prize in Physiology or Medicine for their find in 1901. A year after the discovery, Paul Ehrlich used the term  antibodies  (German  Antikörper ) for these antitoxins.

3. HISTORY…. In 1975, the monoclonal antibody (mAb) technique was created by Georges Köhler, César Milstein, and Niels Kaj Jerne using a mouse x mouse hybridoma. They shared the Nobel Prize in Physiology of Medicine in 1984 for the discovery. Eight years later, in 1992, the US FDA approved the first therapeutic mAb muromonab-CD3 (trade name Orthoclone OKT3) to reduce acute rejection in patients with organ transplants.

4. INTRODUCTION As of now, there are more than 100 mabs have been approved by FDA. These target various tumors, cancers, bacteria, virus, autoimmune disorders, toxins and even for drug antidotes( eg ., Idarucizumab). Right now the pandemic that’s affected everyone, the SARS COV-19 has got several mabs approved for its prophylaxis and mitigation.

5. So what is mAb???... Monoclonal antibody or simply mAb is an antibody synthesized from a single type of cell(thus, monoclonal) while our endogenously produced antibodies are polyclonal(produced by a number of distinct B lymphocytes and therefore have slightly different specificity for the target Ag.

6. How are these produced exactly? Monoclonal antibodies are produced by introducing human genes that produce antibodies into mice or another suitable mammal. The mice then are vaccinated with the desired antigen. This causes the immune cells of the mice to produce the desired human antibody.

7. NOMENCLATURE The first mab was approved in 1985 is named as MUROMONAB-CD3 which depicts as Muro - murine originated(mice) Mon- monoclonal Ab - antibody CD3- against CD3 i.e., against immunity and is approved for preventing tranplantation rejections.

8. Nomenclature… Later in 2006, WHO introduced nomenclature system for mabs. This includes ❶ Prefix- any random ❷Infix- includes their target with a second substem depicting their source- chimeric (xi)/ humanized( zu )/ completely human(u) & ❸suffix- mab

9. SOME INFLIXES WITH THEIR TARGETS Ba : bacterial Ci : cardiovascular De: metabolic or endocrine pathways Eni : enzyme inhibition Fung: fungal Ki : cytokine and cytokine receptor Ne\n: nervous system Os: bone Li: immune system Tu : tumor Tox : toxin Vi: viral

10. Nomenclature… Eg : Adalimumab Here, lim stands as infix which indicates (lymphocytes as in) immune system being the target. U indicates it’s completely human derived & mab denotes it’s a monoclonal antibody. This is TNF blocker approved to use in various autoimmune conditions like Rheumatoid arthritis, Ankylosing Spondylitis , Crohns Disease, Ulcerative Colitis & Psoriatic Spondylitis .

11. Nomenclature… Later in 2017, two changes were made to this. To remove the source as both human and animal derived can produce allergic reaction. To add four alphabets which have no meaning to differentiate between mabs produced by different companies( biosimilars ).

12. TOX(toxin) BEZLOTOXUMAB: Pseudo-membranous colitis by Clostridium difficile ( Clostridioides difficile ) infection. A single molecule of bezlotoxumab neutralizes Toxin B by binding its two Fab regions to two epitopes within the N-terminal half of the Toxin B. OBILTOXAXIMAB: Anthrax by Bacillus anthracis . It is designed to attach to a component of the anthrax toxin called ‘anthrax protective antigen’ that allows the toxin to enter cells. 

13. NE/N(nervous system) ERENUMAB, EPTINEZUMAB, GALCANEZUMAB & FREMANEZUMAB: Prophylaxis of migraine. These mabs acts by blockage of Calcitonin Gene Related Peptide(CGRP) receptors expressed in the trigeminal system – both fibres and ganglia. Inhibition of the effects of CGRP could theoretically reduce the compensatory vasodilation in ischemic-related conditions. 

14. VI(viral) PALIVIZUMAB: Respiratory Syncytial Virus It helps prevent RSV in children less than 24 months old who are at high risk for getting RSV & not used to treat the symptoms.   It is directed to bind to an epitope in the antigenic site of the F protein of respiratory syncytial virus (RSV).

15. CI/C(circulatory system) ABCIXIMAB: Abciximab binds to the glycoprotein (GP) IIb / IIIa receptor of human platelets and inhibits platelet aggregation by preventing the binding of fibrinogen, von Willebrand factor, and other adhesive molecules.  CAPLACIZUMAB: It is a von Willebrand factor ( vWF )-directed antibody fragment used to treat acquired thrombotic thrombocytopenic purpura ( aTTP ).

16. EMICIZUMAB: It restores the function of missing activated factor VIII (FVIII) by bridging FIXa and FX to facilitate effective haemostasis in patients with haemophilia A. It is approved for the routine prophylaxis of bleeding episodes in patients with haemophilia A with or without FVIII inhibitors. 

17. EMICIZUMAB

18. IDARUZUMAB: It targets direct thrombin inhibitor dabigatran , by binding to dabigatran and its acylglucuronide metabolites with higher affinity than the binding affinity of dabigatran to thrombin, neutralizing their anticoagulant effect. 

19. ALIROCUMAB & EVOLOCUMAB: PCSK9 inhibitors. These bind to proprotein convertase subtilisin kexin type 9 (PCSK9). PCSK9 binds to the low-density lipoprotein receptors (LDLR) on the surface of hepatocytes to promote LDLR degradation within the liver . BROLUCIMAB: It inhibits VEGF-A, used as an intravitreal injection Age Related Macular Degeneration. OC(over cholesterol)

20. OS(bone) DENOSUMAB: Osteoporosis by preventing fractures by Inhibiting RANL ligand and preventing osteoclast activity. ROMOSOZUMAB: Osteoporosis by preventing fractures via sclerostin inhibition, thus inhibits osteoclast activity. BUROSUMAB: X-linked hyperphosphotemia it binds to Fibroblast Growth Factor-23, a member of FGF family involved in phosphate and vitamin D metabolism and regulation.

21. KI/K( leukotriene ) IXEKIZUMAB,IL-17 SECUKINUMAB,IL-17 USTEKINUMAB,IL-12,23 RISANKINUMAB,IL-23 GUSELKUMAB,IL-23 TILDRAKIZUMAB,IL-23 All these are used for PS(plaque psoriasis).

22. LI/L(immune system) TNF-alpha inhibitors: ADALIMUMAB, CERTOLIZUMAB ETANERCEPT INFLIXIMAB GOLIMUMAB These are used in autoimmune conditions like Rheumatoid Arthritis, Crohns Disease and Psoriasis

23. P- SELECTIN: CRIZANLIZUMAB- tmca It acts against the adhesion molecule P- selectin causing vaso -occlusion. Thus, it’s used to reduce the number of pain crises (sudden, severe pain that may last several hours to several days) in adults and children 16 years of age and older with sickle cell disease, reduce the frequency of vaso -occlusive crises (VOCs).

24. CD4- IBALIZUMAB It is a viral-entry inhibitor that coats CD4-positive cells, the main target of HIV infection. By blocking viral entry into CD4 cells, ibalizumab creates a barrier for HIV. Ibalizumab leads to conformational changes of the CD4 T cell receptor–gp120 complex thus  preventing HIV fusion and entry . Therefore, ibalizumab is classified as an entry inhibitor.

25. IL-17 RA IL-17 RA- BRODALUMAB Brodalumab  binds to the interleukin-17 receptor and so prevents interleukin 17 (IL-17) from activating the receptor. This mechanism is similar to that of another anti-psoriasis antibody, ixekizumab .

26. IL-4R alpha antagonist- DUPILUMAB It is approved for Atopic Dermatitis. Dupilumab is of immunoglobulin G4 subclass that inhibits IL-4 and interleukin-13 (IL-13) signaling by specifically binding to the IL-4 receptor alpha subunit. By blocking the IL-4R alpha subunit, dupilumab inhibits IL-4 and IL-13 cytokine-induced responses, including the release of proinflammatory cytokines, chemokines , and immunoglobulin E.

27. IFN-alpha- EMPALUMAB Emapalumab is the first global approval for the treatment of pediatric and adult patients with primary hemophagocytic lymphohistiocytosis (HLH) with refractory, recurrent, or progressive disease or intolerance to HLH therapy. It acts by binding and neutralising IFN-γ.

28. C5 Eculizumab: Eculizumab is a recombinant humanized monoclonal antibody used to reduce the risk of hemolysis in paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome ( aHUS ). It targets complement protein C5. Binding to this protein prevents the activation of a complement terminal complex. Ravulizumab: Ravulizumab-cwvz binds to complement protein 5 (C5) and blocks its activation by complement pathway convertases, thus inhibiting the formation of the terminal complement complex.

29. IMMUNE CHECK POINT INHIBITORS Immune checkpoints are made by some types of immune system cells, such as T cells, and some cancer cells. These checkpoints help keep immune responses from being too strong and sometimes can keep T cells from killing cancer cells. When these checkpoints are blocked, T cells can kill cancer cells better. Examples of checkpoint proteins found on T cells or cancer cells include PD-1/PD-L1 and CTLA-4/B7-1/B7-2. Some immune checkpoint inhibitors are used to treat cancer.

30. ●PD1 : NIVOLUMAB- Hodgkins lymphoma, Non-Small Cell Lung Cancer(NSCLC) PEMBROLIZUMAB- NSCLC, Head &Neck tumors CEMIPLIMAB- Squamous cell Ca of skin ●PD-L1 : ATEZOLIZUMAB- Urothelial & breast Ca AVELUMAB- Merkel cell Ca DERVALUMAB- Bladder Ca ●CTLA-4: IPILIMUMAB- Malignant melanoma

31. ASTHMA Ig -E: OMALIZUMAB Omalizumab binds to free IgE in the serum, forming trimers and hexamers and thus inhibiting IgE from binding to its receptos on mast cells and basophils and thus their respective inflammatory mechanisms. IL-5: RESLIZUMAB MEPOLIZUMAB BENRALIZUMAB

32. mAbs approved for COVID ROCHE’S COVID COCKTAIL: this consists of two mabs 1. CASIRIVIMAB & 2. IMDEVIMAB This cocktail has to be administered in patients with mild to moderate infection of Covid and do not require oxygen, but are at high risk of developing severe stage of COVID. MOA: these block COVID virus from entering human cells.

33. Criteria : Only for high risk patients i.e , Age >59yrs; Obese people; Patients with chronic lung disease including asthma; NIDDM & IDDM; Patients with CKD; Immunosuppressed (on chemotherapeutics for cancers, BMD or organ transplantation, immune deficiencies, HIV); Severe CVDs; liver disorders; Sickle cell anaemia ; Thalassemia.

34. CDSCO approved for restricted emergency use for the treatment of mild to moderate COVID-19 in adults & paediatric patients with laboratory confirmed infection and are at high risk of hospitalisation . Efficiency : it is proven to reduce hospitalisation by upto 70% in eligible candidates(12yrs and above, weight>40kg, not hospitalised patients and do not require o2 supplementation when administered within 3-4 days or 7days of onset of symptoms as soon as possible.

35. Safety profile: safe for patients with Chronic Kidney Disease, Chronic Liver Disease and immunosuppressed as well. Adverse Drug Reactions: possible side effects includes fever, difficulty in breathing, chills, fatigue, nausea, headache, throat irritation & rashes severe hypersensitivity reactions rarely occur.

36. IL-6Receptor Tocilizumab Sarilumab Both of these are approved for the treatment of rheumatoid arthritis and other autoimmune conditions Satralizumab : it is used in neuromyelitis optica spectrum disorder ( NMOSD ) . NMOSD is a rare, chronic autoimmune disease that causes inflammation in the central nervous system. This can lead to damage of the optic nerves, spinal cord, and/or brain.

37. Interleukin (IL)-6 is a pleiotropic , proinflammatory cytokine produced by a variety of cell types, including lymphocytes, monocytes , and fibroblasts. Infection by SARS- CoV induces a dose-dependent production of IL-6 from bronchial epithelial cells. COVID-19-associated systemic inflammation and hypoxemic respiratory failure can be associated with heightened cytokine release, as indicated by elevated blood levels of IL-6, C-reactive protein (CRP), D- dimer , and ferritin .

38. It is hypothesized that modulating IL-6 levels or the effects of IL-6 may reduce the duration and/or severity of COVID-19. There are two classes of Food and Drug Administration (FDA)-approved IL-6 inhibitors: anti-IL-6 receptor monoclonal antibodies ( mAbs ) (e.g., sarilumab , tocilizumab ) and anti-IL-6 mAbs (i.e., siltuximab ). These drugs have been evaluated in patients with COVID-19 who have systemic inflammation.

39. Tocilizumab and sarilumab   should be used with caution  in groups of patients with COVID-19 that have not been adequately studied in clinical trials. This includes patients who are significantly immunosuppressed , particularly those who have recently received other biologic immunomodulating drugs, and those with: Alanine transaminase levels >5 times the upper limit of normal A high risk for gastrointestinal perforation An uncontrolled serious bacterial, fungal, or non-SARS-CoV-2 viral infection Absolute neutrophil counts <500 cells/µL Platelet counts <50,000 cells/µL Known hypersensitivity to the drug

40. Tocilizumab and sarilumab should only be given in combination with a course of dexamethasone (or an alternative corticosteroid at a dose that is equivalent to dexamethasone 6 mg) the Panel recommends  sarilumab  only when tocilizumab is not available or is not feasible to use  ( BIIa )  because the evidence for the efficacy of tocilizumab is more extensive than that for sarilumab

41. Adverse Effects The primary laboratory abnormalities reported with tocilizumab treatment are elevated liver enzyme levels that appear to be dose dependent. Neutropenia or thrombocytopenia are uncommon. In randomized trials, no excess secondary infections were seen among patients who received combination therapy compared to study controls. Additional adverse effects, such as serious infections (e.g., tuberculosis [TB], bacterial or fungal infections) and bowel perforation, have been reported.

42. Drug name Dosing regimen Comments Tocilizumab Tocilizumab 8 mg/kg actual body weight (up to 800 mg) administered as a single IV dose In clinical trials, a third of the participants received a second dose of tocilizumab 8 hours after the first dose if no clinical improvement was observed. Sarilumab Use the single-dose, pre-filled syringe (not the pre-filled pen) for SQ injection. Reconstitute sarilumab 400 mg in 100 cc 0.9% NaCl and administer as an IV infusion over 1 hour. Use as an alternative if tocilizumab is not available or not feasible to use  ( BIIa ) . In the United States, the currently approved route of administration for sarilumab is SQ injection. In the REMAP-CAP trial, the SQ formulation was used to prepare the IV infusion.

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