Targeted Therapies

• Monoclonal antibodies: antibodies (four molecules assembled by disulfide bridges) secreted by B lymphocytes, that recognize only one type of epitope on a given antigen. They are by definition all identical and produced by a single plasmocyte (lymphocyte B) cell clone.

• Tyrosine kinase: Tyrosine kinases are proteins that cells use to signal to each other to grow.

They act as chemical messengers. There are a number of different tyrosine kinases and block-ing them stops the cancer cells growblock-ing. More exactly, a tyrosine kinase is an enzyme capa-ble of transferring a phosphate group from ATP to a protein within a cell. It functions as an on/off switch in many cellular functions, including the intracellular signaling cascade resulting from the activation of various receptors as EGFR (Epidermal Growth Factor Receptor), VEGF (Vascular Endothelial Growth Factor), or PDGFR (Platelet-derived growth factor receptor) re-ceptors. There are a lot of tyrosine kinase inhibitors on the market whose name finishing with

“tinib” or “fenib”: BOSUTINIB, CRIZOTINIB, DABRAFENIB, DASATINIB, ERLOTINIB, IMATINIB, LESTAURTINIB, NILOTINIB, PONATINIB, REGORAFENIB, RUXOLITINIB, SORAFENIB, SUNITINIB, TOFACITINIB, VEMURAFENIB, and others.

We also have the emergence of other approaches, i.e. targeted therapies, alongside cytotoxic chemother-apies. The possible points for the application of targeted therapies are:

• Growth signaling pathways. Certain messengers of proliferation induce cancer cells to multi-ply. If the corresponding receptors located on the surface of the cell or the signaling pathways within the cells are blocked, the tumor can no longer grow:

– Monoclonal antibody directed against Her-2 receptor: HERCEPTIN (Trastuzumab), which is a humanized monoclonal antibody. It is indicated for the thargeted therapy of metastatic breast cancer overexpressing the receptor HER-2. It is administered alone or in combination with chemotherapy, but not anthracyclines which are strongly contraindi-cated, or in combination with hormone therapy. It is also indicated for metastatic gastric cancer with tumor overexpression of HER-2, in combination with CAPECITABINE or 5-FLUOROURACIL and CISPLATIN. The adverse effects of HERCEPTIN are:

∗ Cardiotoxicity: before administration, the ventricular ejection fraction has then to be controlled.

∗ Allergic reactions or hypersensitivity.

∗ Arthralgia, myalgia and flu-like illness.

– Monoclonal antibody directed against EGFR : CETUXIMAB=Erbitux, which is a Chimeric monoclonal antibody. Indeed, the activation of EGFR leads to cell prolifera-tion, angiogenesis, inhibition of apoptosis and to metastases. CETUXIMAB blocks the binding of endogenous ligands to EGFR, induces an internalization of EGFR and recruits cytotoxic immune effector cells against tumor cells expressing EGFR. It is indicated for metastatic colorectal cancer with wild-type KRAS gene expressing epidermal growth fac-tor recepfac-tor (EGFR), in monotherapy or in combination with chemotherapy. It is also indicated for epidermioid carcinoma (locally advanced stage) of the upper aerodigestive tract in combination with radiotherapy and platinum-based chemotherapy for recurrent and/or metastatic disease. The adverse effect are of cutaneous type: most commonly acne eruption, cutaneous xerosis, pruritus, nail disorders (paronychiae) and hypertrichosis.

– Monoclonal antibody directed against CD-20 antigen: RITUXIMAB=Mabthera. The antigen CD-20 is a protein present on the surface of B lymphocytes, and it plays a role in

their maturation. It is indicated in diffuse aggressive non-Hodgkin’s lymphoma (CD20 +), in chronic lymphocytic leukemia and in rheumatoid arthritis in combination with METHOTREXATE. The adverse effects are injection reactions: temperature, chills, nau-sea, asthenia, pruritus.

– Tyrosine kinase inhibitors of EGFR:

∗ ERLOTINIB=Tarceva. It is indicated for non-small cell lung cancer in locally ad-vanced or metastatic forms and in metastatic pancreatic cancer, in combination with gemcitabine. The adverse effects are cutaneous: rash, acneiform skin rashes, and diarrhea.

∗ GEFTINIB=Iressa. It is indicated for adults in the treatment of locally advanced or metastatic non-small cell lung cancer with mutations activating EGFR tyrosine kinase. The adverse effects are cutaneous: rash, acneiform skin rashes, and diarrhea.

– Inhibitor of bcr-abl tyrosine kinase present in the Philadelphia chromosome: IMA-TINIB (Glivec), DASAIMA-TINIB (Sprycel ), NILOIMA-TINIB (Tasigna), BOSUIMA-TINIB (Bosulif) and POMATINIB (Iclusig). The Philadelphia chromosome is an acquired chromosomal abnormality of hematopoietic stem cells that is associated with chronic myeloid leukemia (CML). Also known as t(9; 22) (q34; q11), according to the International System for Hu-man Cytogenetic Nomenclature (ISCN) , the Philadelphia chromosome is the result of a reciprocal translocation (or exchange of genetic material) between chromosomes 9 and 22 resulting in fusion of genes BCR (Breakpoint Cluster Region) and ABL (Abelson), which forms the BCR-ABL fusion gene. The rearranged DNA comprises the ABL gene encod-ing a cytoplasmic tyrosine kinase and whose activity becomes constitutive (permanent) by fusion with the BCR gene. Therefore, there is an excessive and persistent production in the bone marrow of the white blood cells (or leukocytes). Some of these white blood cells are abnormal; they are immature cells, that is to say, their development is not completed when they pass into the bloodstream. These inhibitors of tyrosine kinase are given orally in continuous administration. The aim is to obtain a complete haematological response at 3 months (normal hemogram, disappearance of clinical signs), a complete cytogenetic response (CCR) (disappearance of the translocation t(9; 22) to the medullary karyotype) at 12 months and a major molecular response at 12-18 months (reduction of blood transcript Bcr-Abl i.e. less than a threshold). IMATINIB remains the most used in the first line, 95 per cent of hematological response, 75 per cent of CCR are obtained. Results over 10 years are excellent. NILOTINIB (more powerful) also has an indication in 1st line, but it is asso-ciated with increased vascular toxicity. The same applies to DASATINIB assoasso-ciated with risk of pleural effusion and pulmonary arterial hypertension. The Resistance to imatinib may appear: acquired mutation of domain BCR-ABL kinase , BCR-ABL amplification, which can be overtaken by 2nd generation tyrosine kinase inhibitors. This continuous treatment should never be stopped (except for particular protocols), if it is effective and the tolerance is acceptable. IMATINIB is also indicated for Acute lymphoblastic leukemia with Philadelphia Chromosome.

– Tyrosine kinase inhibithor of PDGFR and c-kit: IMATINIB. The c-kit is a receptor tyrosine kinase, which is involved in intracellular signaling, and the mutated form of c-kit plays a crucial role in occurrence of some cancers, such as gastrointestinal stromal tumor, acute myeloid leukemia, melanoma, and other tumors. IMATINIB is indicated for GIST (gastrointestinal stromal tumors) with c-kit mutation. The adverse effects of IMATINIB are of hematologic order: leukopenia, anemia, thrombocytopenia, of digestive

order: nausea, vomiting, diarrhea, dyspepsia, abdominal pain, of cutaneous order: peri-orbital edema, dermatitis, eczema, rash hydric retention, and also asthenia, muscle pain, arthralgia, and headaches.

• Neoangiogenesis. The more the volume of the tumor increases, the more oxygen and nutrients it needs. The normal blood vessels do not allow the tumor to be supplied in sufficient quan-tities. At some point, the tumor cells will initiate the formation of new blood vessels. This phenomenon is called angiogenesis. The growth factor at the origin of this formation of vessels is VEGF, which is secreted by the tumor; it can be blocked by angiogenesis inhibitors. Without these new vessels, the tumor would not be fed. Without resources, it could not develop. The angiogenesis inhibitors are monoclonal antibodies directed against VEGF or tyrosine kinase inhibithors of VEGF, that we present hereafter.

– Monoclonal antibody directed against VEGF: BEVACIZUMAB=Avastin. It causes the inhibition of the binding of VEGF to one of its receptors on the surface of endothelial cells (VEGFR-1, VEGFR-2) and the neutralization of the biological activity of VEGF, which leads to the decrease in tumor vascularization and inhibition of tumor growth. It is indicated for:

∗ Metastatic colorectal cancer in combination with fluoropyrimidine-based chemother-apy.

∗ Metastatic breast cancer, in combination with PACLITAXEL or in combination with CAPECITABIN.

∗ Non-small cell lung cancer, advanced where the surgery is not possible, metastatic or relapsed, provided that the histology is not predominantly squamous, in combination with platinum-based chemotherapy.

∗ Advanced and/or metastatic kidney cancer.

The adverse effects are: high blood pressure, venous and arterial thrombo-embolism, hem-orrhage, proteinuria, healing disorders, nasal or gastrointestinal septum perforations.

– Tyrosine kinase inhibithors of VEGF: SUNITINIB=Sutent and SORAFENIB=Nexavar.

They bind to the ATP-dependent catalytic site of the tyrosine kinase domain of VEGFR, which induces the blocking of intracellular signaling. They therefore lead to the inhibition of proliferation and of angiogenesis and to the induction of apoptosis.

– Multikinase inhibitor: SORAFENIB=Nexavar: anti: RAF-1, B-RAF, 2, VEGFR-3, PDGFR-β, FLT-VEGFR-3, c-kit. It has anti-proliferative and anti-angiogenic effects. It is indi-cated for advanced or metastatic renal cancer (after failure of immunotherapy) and hep-atocellular carcinoma. The adverse effects are: skin rash, diarrhea, hand-foot syndrome (hyperkeratosis), asthenia and high blood pressure.

– Multi-target tyrosine kinase inhibitor: VEGFR, PDGFR, c-kit: SUNITINIB=Sutent.

It is indicated for: gastrointestinal stromal tumors (GIST), advanced and/or metastatic kidney cancer after immunotherapy failure and neuroendocrine tumors of pancreas, not resectable or metastatic, well differentiated, with progression of the disease in adults. The adverse effects are alopecia, asthenia, headache and dizziness. The hematologic adverse effects are: leukopenia, anemia and thrombocytopenia. The digestive adverse effects are:

nausea, vomiting, diarrhea, constipation and abdominal pain. The skin adverse effects are:

skin rash, hair color change, hand-foot syndrome.

• Slowed immune response. Some proteins, whose prevent the cells of the body’s immune system from identifying the tumor as a foreign body and fighting it can be activated on the surface of tumor cells. With the blocking of these proteins from the control points of the immune system, the tumor can once again be combated: obstacles to the immune response are removed.

Modifiers of the immune response are used for this aim.

The immune response is a complex, imperfectly elucidated phenomenon, the purpose of which is the defense of the organism. In humans, it mainly involves two mechanisms: cell-mediated immunity and humoral-mediated immunity (antibody production). These two types of response have a high level of specificity with respect to antigenic epitopes expressed on the molecular components of infectious agents, heterologous tissues (grafts), transformed cells (cancers), or even pathologically on autologous cells (autoimmunity). Several cell types contribute to the immune response and interact with each other in successive activation cascades and include negative feedback loops (Figure 14.1 ). Several soluble factors, cytokines, are secreted by the immune cells at different stages of the cascade, allowing initiation and/or regulation of cellu-lar cooperation. The cytokines present cell growth factor properties and/or cellucellu-lar activation properties which stimulate proliferation, or maturation, or activation/inactivation. Each of them generally has multiple actions that are a function of the exposed cell type and act in synergy.

Figure 14.1: Cell population involved in immune response

Examples of cytokines in the immune response are:

– Interleukin-2 (IL-2, proleukine) that stimulates the proliferation of lymphocytes T helper and lymphocytes T cytotoxic. It is a human recombinant cytokine (IL-2-rh).

∗ Action mode and indications: By binding to IL-2 receptors of immune cells respond-ing to an antigenic stimulus, it induces their proliferation and differentiation in T-helper and T-cytotoxic (LAK: lymphocyte activated killer). It also induces B-cell proliferation, stimulates macrophage activity and increases the toxicity of NK (nat-ural killer) cells. IL-2 is also an inducer of α-interferon (INF-α). To date, IL-2 has two indications that are metastatic kidney cancer for which 15 per cent of objective responses are reported and malignant metastatic melanoma for which 17 per cent of objective responses are reported.

∗ Administration way and metabolism: IL-2 is administered intravenously. The plas-matic half-life is about 1 hour. The product is metabolized at the renal level by the epithelium of the kidney proximal tubule. Neutralizing circulating antibodies are not observed.

∗ Adverse effects: The main adverse effects include capillary vascular leakage leading to edema (pulmonary) and hypotension in 75 per cent of patients, inflammatory syn-drome reflected by flu-like synsyn-drome (fever, chills, arthralgia), cardiac arrhythmia, gastro-intestinal disorders (nausea, vomiting, diarrhea), psychiatric disorders associ-ated with confusion and depression, at the hematological level: anemia, thrombocy-topenia and granulopenia may be observed.

– Interferon (INF) α, that activates macrophages, T lymphocytes and natural killers. In-terferons used in therapeutics are recombinant human proteins having the same properties as natural cytokines. At low dose, INF-α increases the cytotoxic activity of activated lymphocytes and it has an anti-mitotic activity. INF-α-2b (ROFERON) has received an indication in hairy cell leukemia, CML, Kaposi, melanoma, kidney cancer, hepatitis B and C. The adverse effects are essentially flu-like syndrome (fever, myalgia, arthralgia) and thrombocytopenia.

Recently, new monoclonal bodies stimulating the immune response appeared, as:

– IPILIMUMAB=Yervoy, which is anti-CTLA-4. CTLA-4 (cytotoxic T-lymphocyte-associ-ated protein 4) is a protein receptor that, functioning as an immune checkpoint, downreg-ulates immune responses and transmits an inhibitory signal to T cells. IPILIMUMAB is a monoclonal antibody used in the treatment of advanced melanoma. IPILIMUMAB can cause serious side effects in many parts of your body which can lead to death. These se-rious side effects may include: intestinal problems (colitis) that can cause tears or holes (perforation) in the intestines; liver problems (hepatitis) that can lead to liver failure; skin problems that can lead to severe skin reaction; nerve problems that can lead to paralysis;

hormone gland problems (especially the pituitary, adrenal, and thyroid glands); and eye problems.

– PEMBROLIZUMAB=Keytruda, is a new monoclonal antibody anti-PD-1 (programmed death-1), antibody that potentiates T cell responses, including anti-tumor responses. PD-1 is a cell surface receptor expressed on T cells, that plays an important role in down-regulating the immune system, supresses T cell inflammatory activity and promotes apop-tosis of T cells. PEMBROLIZUMAB is indicated for patients with advancd melanoma

(non resectable or metastatic). Keytruda can cause that the immune system attacks normal organs and tissues in any area of the body and can affect the way they work. These prob-lems can sometimes become serious or life-threatening and can lead to death. The main adverse effects of Keytruda are

∗ Lung problems (pneumonitis). Symptoms of pneumonitis may include shortness of breath, chest pain, or new or worse cough.

∗ Intestinal problems (colitis) that can lead to tears or holes in the intestine. Signs and symptoms of colitis may include diarrhea or more bowel movements than usual;

stools that are black, tarry, sticky, or have blood or mucus; or severe stomach-area (abdomen) pain or tenderness.

∗ Liver problems (hepatitis). Signs and symptoms of hepatitis may include yellowing of the skin or the whites of the eyes, nausea or vomiting, pain on the right side of the stomach area (abdomen), dark urine, feeling less hungry than usual, or bleeding or bruising more easily than normal.

∗ Hormone gland problems (especially the thyroid, pituitary, adrenal glands, and pancreas). Signs and symptoms that the hormone glands are not working properly may include rapid heartbeat, weight loss or weight gain, increased sweating, feeling more hungry or thirsty, urinating more often than usual, hair loss, feeling cold, con-stipation, the voice gets deeper, muscle aches, dizziness or fainting, or headaches that will not go away or unusual headache.

∗ Kidney problems, including nephritis and kidney failure. Signs of kidney prob-lems may include change in the amount or color of urine.

∗ Problems in other organs. Signs of these problems may include rash, changes in eyesight, severe or persistent muscle or joint pains, severe muscle weakness, low red blood cells (anemia), shortness of breath, irregular heartbeat, feeling tired, or chest pain (myocarditis).

∗ Infusion (Intravascular) reactions that can sometimes be severe and life-threatening.

Signs and symptoms of infusion reactions may include chills or shaking, shortness of breath or wheezing, itching or rash, flushing, dizziness, fever, or feeling like passing out.

Another monoclonal antibody anti-PD-1 is NIVOLUMAB= Optivo. PD-1 binds two ligands, PD-L1 and PD-L2. These monoclonal antibodies are also indicated for Hodgkin’s disease and lung cancer.

– ATEZOLIZUMAB=Tecentriq, is a human monoclonal antibody directed against ligand PD-L1. It is indicated for bladder cancers, non-small cell lung cancers and kidney cancers.

The adverse effects of ATEZOLIZUMAB are: herpes simplex encephalitis, infection, mycobacterium infection, retroperitoneal hemorrhage, sepsis, severe infection, urinary tract infection, colitis, diarrhea, and increased thyroid stimulating hormone level.

• Antitumor vaccines, like vaccines against humain papillomavirus humains (HPV) for the pre-vention of the cancer of the cervix.

We summarize hereafter a table showing specific or particularly severe and/or serious adverse effects related to anti-cancer therapies drugs.

Anti-cancer drug or class Nature of the adverse reaction Prevention

CISPLATIN Nephrotoxicity

BLEOMYCIN, BUSULFAN pulmonary fibroses

5-FLUOROURACIL Cardiac complications (angina)

Cetuximab Acneiform eruptions

CYCLOPHOSPHAMIDE hemorrhagic cystitis prevention by mesna

IRINOTECAN Secretory diarrhea

METHOTREXATE, L-asparginase Hepatic impairment OXALIPLATIN, vinca-alkaloids Neurotoxicity

METHOTREXATE tubulopathy, renal failure Prevention by alkaline hyperhydration Anthracyclines, trastuzumab heart failure Cumulative, imposing a maximum dose