TYROSINE KINASE
      INHIBITORS


        PRESENTED BY:
           Y.VIJAY
  FINAL YEAR POST GRADUATE
DEPARTMENT OF PHARMACOLOGY
  OSMANIA MEDICAL COLLEGE
CONTENTS
• INTRODUCTION
• TYPES OF TYROSINE KINASES
• ROLE OF KINASES IN SIGNALLING
  PATHWAYS
• DRUGS TARGETTING TYROSINE
  KINASES
• CONCLUSION
• REFERECES
INTRODUCTION
• PROTEIN KINASES:
• Protein kinases are a group of enzymes
  that possess a catalytic subunit that
  transfers the gamma (terminal)phosphate
  from nucleotide triphosphates (often ATP)
  to one or more amino acid residues in a
  protein substrate side chain, resulting in a
  conformational change affecting protein
  function.
CATEGORIES OF PROTEIN KINASES

•  Classified into three different categories:
1. Kinases that specifically phosphorylate
   tyrosine residues
2. Kinases that phosphorylate serine and
   threonine residues, and
3. Kinases with activity toward all three
   residues.
TYPES OF TYROSINE KINASES
•    Tyrosine kinases can be further
     subdivided into

1. Receptor tyrosine kinases
   eg: EGFR, PDGFR, FGFR

2. Non-receptor tyrosine kinases
   eg: SRC, ABL, FAK and Janus kinase
T Y OSI N KI N
   R     E    ASE ST R U T U E
                        C R
                          Extracellular
                          Domain




                          Transmembrane
                            Domain

        TK                Intracellular
                          Domain
RTK structure/function




                         Regulatory
                         domains
Oncogenic activation of Tyrosine kinase

•   Normally the level of cellular tyrosine
    kinase phosphorylation is tightly
    controlled by the antagonizing effect of
    tyrosine kinase and tyrosine
    phosphatases.
•   Some Common mechaninsms of
    oncogenic activation:
     1. Activation by mutation
     2. BCR-ABL and human leukemia
TYROSINE KINASE INIBITORS

1. BCR-ABL Tyrosine Kinase Inhibitors eg: Imatinib
   Mesylate, Dasatinib, and Nilotinib.

2. Epidermal Growth Factor Receptor
   TyrosineKinase Inhibitors eg: Gefitinib, Lapatinib.

3. Vascular Endothelial Growth Factor
   TyrosineKinase Inhibitors eg. Semaxinib, Vatalanib,
   Sunitinib, Sorafenib.
BCR-ABL Tyrosine Kinase Inhibitors
• Mechanism of action :

• IMATINIB & NILOTINIB: bind to a
  segment of the kinase domain that fixes
  the enzyme in a closed or nonfunctional
  state, in which the protein is unable to bind
  its substrate/phosphate donor, ATP.

• DASATINIB: binds both the open and
  closed configuration of BCR-ABL kinase.
BCR-ABL Tyrosine Kinase Inhibitors
• PHARMACOKINETICS 0f Imatinib / Dasatinib
• Absorption
   – Oral bioavailability ~ 98%
• Distribution – highly protein bound
• Metabolism - Primarily by CYP3A4
• Elimination
   – Fecal ~ 65-80% renal ~ 10-13%
   – Half life = Imatinib-18 hrs, N-desmethyl derivative- 40 hrs
                 Dasatinib- 3-5 hrs
                 Nilotinib- 17 hrs
IMATINIB MESYLATE
• First molecularly targeted protein kinase
  inhibitor to receive FDA approval.
• It targets the BCR-ABL tyrosine kinase,
  which underlies chronic myelogenous
  leukemia (CML).
• BCR-ABL tyrosine kinase is present in
  virtually all patients with chronic
  myelogenous leukemia (CML) and some
  patients with acute lymphoblastic leukemia
  (ALL)
IMATINIB MESYLATE
           Dosing and Administration

• Treatment of Philadelphia chromosome(+) chronic
  myelogenous leukemia

  – Chronic phase, initial therapy
     • 400 mg PO once daily - continue as long as the
       patient continues to benefit
     • May increase to 600 mg PO once daily
  – Accelerated phase or blast crisis
     • 600 mg PO once daily - continue as long as the
       patient continues to benefit
     • May increase to 800 mg/day PO
IMATINIB MESYLATE
• Toxicity
• Gastrointestinal
    – Nausea, vomiting, abdominal pain
• Edema
    – Periorbital edema or peripheral edema in the lower
      extremities
•   Diarrhea
•   Muscle cramps
•   Fatigue
•   Skin rash
•   Cytopenias
Imatinib (Gleevec®)
        FDA Approved Indications
• Chronic Myeloid Leukemia
• Pediatric CML
• Acute Lymphoblastic Leukemia
• Gastrointestinal Stromal Tumors
• Myelodysplastic/Myeloproliferative
  Diseases
• Aggressive Systemic Mastocytosis
• Hypereosinophilic Syndrome/Chronic
  Eosinophilic Leukemia
• Dermatofibrosarcoma Protuberans
DASATINIB

• Multi-kinase inhibitor
• BCR-ABL, SRC family, c-KIT, EPHA2,
  PDGFRβ
• FDA Approved Indications
  – Treatment of adults with chronic, accelerated,
    or myeloid or lymphoid blast phase CML
  – Treatment of adults with Philadelphia-
    chromosome (+) ALL with resistance or
    intolerance to prior therapy
NILOTINIB

• Indication: treatment of chronic phase
  and accelerated phase Philadelphia
  chromosome positive chronic
  myelogenous leukemia (CML) in adult
  patients resistant to or intolerant to prior
  therapy that included imatinib.
NILOTINIB

• Pharmacokinetics
• Absorption
   – Peak plasma levels – 3 hours
   – Approximately 30% of an oral dose of Nilotinib is
     absorbed after administration
   – Food (fatty meal) increases absorption
• Distribution
   – Highly protein bound
   – Plasma concentrations reach a steady state only after
     8 days of daily dosing
NILOTINIB

Toxicities
• Thrombocytopenia and Neutropenia
• QT-prolongation – with sudden death
  reported
• Liver function abnormality – elevated
  bilirubin,AST/ALT and alkaline
  phosphatase
• Electrolyte abnormality ( hyper and hypo
  K, hypo Mg, Phos, Ca, Na)
Mechanism of resistance to Bcr-Abl
            kinase inhibitors
• POINT MUTATIONS
  CONTACT POINTS BETWEEN Imatinib and the
  enzyme become the sites of mutation.

• Amplification of Wild type of Kinase gene

• Philadelphia –ve clones.
Epidermal Growth Factor Receptor
    TyrosineKinase Inhibitors

• Gefitinib,
• Erlotinb
• Lapatinib
Epidermal Growth Factor Receptor
    TyrosineKinase Inhibitors
• Mechanism of Action of Gefitinib / Erlotinib
   Inhibit the EGFR tyrosine kinase by virtue of
  competitive blockade of ATP binding
• Selectively inhibits EGFR-TK
    Blockage of downstream EGFR signal transduction
     pathways, cell cycle arrest, and inhibition of
     angiogenesis
Epidermal Growth Factor Receptor
    TyrosineKinase Inhibitors
• Pharmacokinetics of Gefitinib / Erlotinib
Absorption
   – Peak plasma levels occurs 3-7 hours after dosing
   – Mean bioavailability of 60%
   – H2 Blockers and Proton pump inhibitors reduce plasma
      concentrations.
Distribution
   – 90% protein bound
Metabolism
   – Predominantly via CYP3A4
Elimination
   – Half life – Gefitinib- 48 hrs, Erlotinib- 36 hrs
   – Fecal 86%, renal elimination < 4%
GEFITINIB
• Toxicities
• Dermatologic
  – Rash, acne, xerosis, pruritus
• Gastrointestinal
  – Diarrhea, Nausea, vomiting, anorexia
• Ocular
  – Pain and corneal erosion/ulcer, aberrant
    eyelash growth
GEFITINIB
Toxicities
• Pulmonary
   – Interstitial lung disease, consisting of interstitial
     pneumonia, pneumonitis, and alveolitis
   – In the event of acute onset or worsening of
     pulmonary symptoms (e.g., dyspnea, cough,
     fever), gefitinib treatment should be interrupted
     and the symptoms promptly investigated
   – If interstitial lung disease is confirmed, gefitinib
     therapy should be discontinued
GEFITINIB
• Drug Interactions
• CYP 3A4 inducers and inhibitors
• Warfarin: reports of elevations in INR
  values and/or bleeding events
  – Monitor INR regularly
• H2-blockers and proton pump inhibitors:
  may ↓ plasma concentrations
  – May potentially reduce Gefitinib efficacy
GEFITINIB
               INDICATIONS
• Non-small Cell Lung Cancer (NSCLC)
  Monotherapy for continued treatment of locally
  advanced or metastatic NSCLC after failure of
  both platinum-based and Docetaxel regimens

• PRESENT INDICATION: NSCLC – patient’s with
  proven response prior to FDA “withdrawal” of
  approval or on a clinical trial
ERLOTINIB
It is a Quinazolinamine inhibitor of HER1/EGFR
   tyrosine kinase.
INDICATIONS
– approved for second-line treatment of patients with
   locally advanced or metastatic non–small cell lung
   cancer.
– Erlotinib also is approved for first-line treatment of
   patients with locally advanced, unresectable, or
   metastatic pancreatic cancer in combination with
   Gemcitabine.
Unlabeled Uses
– Treatment of Squamous cell head and neck cancer
ERLOTINIB
Mechanism of Action:
• Blockage of downstream EGFR signal
  transduction pathways, cell cycle arrest,
  and inhibition of angiogenesis
• Erlotinib competitively inhibits ATP binding
  at the active site of the kinase
ERLOTINIB
   ADVERSE DRUG REACTIONS
• Pulmonary (not life-threatening)
  – Dyspnea
  – cough (33%)
• Rash (75%)
  – Median time to onset 8 days (2-14 days)
• Gastrointestinal
  – Diarrhea (54%, onset ≈12 days)
  – anorexia ,
  – nausea/vomiting (33%/23%)
• Fatigue (52%)
ERLOTINIB
  ADVERSE DRUG REACTIONS
• Ocular
  – Irritation, conjunctivitis (12%) and keratoconjunctivitis
    sicca (12%), corneal ulcerations; reports of NCI CTC
    grade 3 conjunctivitis and keratitis
• Hepatotoxicity
  – Asymptomatic ↑ in liver enzymes, including
    hyperbilirubinemia
• Bleeding events
  – Gastrointestinal bleeds, elevations in INR values in
    patients receiving concomitant warfarin administration
LAPATINIB
• LAPTINIB is a 4-anilinoquinazoline kinase
  inhibitor of the intracellular tyrosine kinase
  domains of both EGFR and HER2 receptors
• Mechanism of Action
  Lapatinib and other pan-HER inhibitors block both
  ErbB1 and ErbB2 and bind to an internal site on
  the receptor (usually the ATP-binding pocket)
• It also binds to inhibits a truncated form of HER2
  receptor that lacks a Trastuzumab binding domain.
LAPATINIB
• INDICATION:
• Metastatic Breast Cancer in combination with
  Capecitabine in patients whose tumors
  overexpress HER2 and who have received
  prior therapy including an Anthracycline, a
  Taxane, and Trastuzumab
LAPATINIB
• Pharmacokinetics
• Absorption
  – Peak plasma levels – 4 hours
  – Food increases absorption
• Distribution
  – Highly protein bound
• Metabolism
  – Extensive metabolism via CYP3A4, CYP3A5
• Elimination
  – Half-life = 24 hours
  – Hepatic metabolism
LAPATINIB
• Dosage and Administration
• Dosage Forms
  – 250 mg tablets
• Administration
  – In combination with Capecitabine, for the treatment of
    advanced or metastatic breast cancer which overexpresses
    HER2 and have received prior therapy including an
    Anthracycline, a Taxane, and Trastuzumab.
  – 1250mg (5 tabs) PO once daily, Days 1-21 on an empty
    stomach
LAPATINIB
• Dosage adjustment
• Renal – No adjustments.
• Hepatic
  – Severe impairment: dose reduction to
    750mg/day should be considered
• Cardiac
  – Therapy should be stopped for:
    • > Grade 2 LVEF dysfunction
    • LVEF less than lower limit of normal
LAPATINIB
• Toxicities
When combined with Capecitabine
• Diarrhea
• Palmar-plantar erythrodysesthesia
• Nausea/vomiting
• Rash
• Fatigue
• Decreases in LVEF
• ECG changes
Vascular Endothelial Growth
Factor TyrosineKinase Inhibitors
1.   Semaxinib [with drawn]
2.   Vatalanib,
3.   Sunitinib,
4.   Sorafenib.
SUNITINIB
• Mechanism of Action
• Inhibitor of multiple receptor tyrosine
  kinases, some of which are implicated in
  tumor growth, pathologic angiogenesis,
  and metastatic progression of cancer.
• competitively inhibits the binding of ATP to
  the tyrosine kinase domain on the VEGF
  receptor-2
SUNITINIB
• Pharmacokinetics
• Absorption
  – Peak plasma levels occur 6-12 hours after dosing
  – Food has no effect on bioavailability
• Distribution
  – 90 - 95% protein bound
• Metabolism
  – Predominantly via CYP3A4
SUNITINIB
• Pharmacokinetics
• Sunitinib is metabolized by CYP3A4 to produce an
  active metabolite SU12662
• the t1/2 of which is 80-110 hours
• steady-state levels of the metabolite are reached after
  ~2 weeks of repeated administration of the parent
  drug.
• The pharmacokinetics of Sunitinib are not affected by
  food intake.
SUNITINIB
• Pharmacokinetics
• Elimination
  – Primarily via feces (61%)
  – 16% renal elimination
  – Half life: Parent compound (40-60hrs), active
    metabolite (80-110hrs)
SUNITINIB
• Dosage and Administration
• Dosage Forms
  – 12.5 mg, 25 mg, 50 mg capsules
• Administration
  – Oral, with or without food
• Dosing
  – For advanced RCC and GIST
     • 50 mg PO once daily, on a schedule of 4 weeks on
       treatment followed by 2 weeks off
SUNITINIB
                   Toxicities
•   QT-prolongation
•   Left Ventricular Dysfunction
•   Hemorrhagic Events
•   Hypertension (30%)
•   Hypothyroidism – baseline thyroid function and
    monitor for signs
SUNITINIB
                    Toxicities
• Adrenal Insufficiency
• GI distress
  – Diarrhea, nausea, vomiting, stomatitis, dyspepsia
• Skin discoloration
• Fatigue
SORAFENIB
Mechanism of Action
• Multi-kinase inhibitor
• Targets RAF/MEK/ERK signaling pathway to inhibit
  cell proliferation
• Inhibits the VEGFR-2/PDGFR-β signaling cascade to
  inhibit angiogenesis
SORAFENIB
Pharmacokinetics
• Absorption
  – Peak plasma levels achieved in ~3 hours
  – Food reduced bioavailability by ~29%


• Distribution
  – Protein binding 99.5%
SORAFENIB
Pharmacokinetics
• Metabolism
  – Primarily by CYP3A4
  – Eight metabolites identified
  – Pyridine N-oxide has shown in vitro potency
    similar to the parent drug.
• Excretion
  – 77% Feces
  – 19% Urine
SORAFENIB
                 Toxicities
•   Hand-foot syndrome, alopecia, rash
•   Diarrhea or constipation
•   Nausea/vomiting, abdominal pain
•   Fatigue
•   High blood pressure
•   Bleeding
•   Neuropathy, joint pain
•   Dyspnea
VATALANIB
• Small molecule protein kinase inhibitor that
  inhibits angiogenesis
• It inhibits all known VEGF receptors, as well
  as platelet-derived growth factor receptor-beta
  and c-kit.
• Most selective for VEGFR-2.
VATALANIB
•  It is being studied as a single agent and in
   combination with chemotherapy in patients with
1. Colorectal cancer and liver metastases,
2. Advanced prostate cancer
3. Renal cell cancer
4. Relapsed/refractory Glioblastoma multiforme.
SUMMARY
• Targeted therapy provides a new approach for
  cancer therapy that has the potential for avoiding
  some of the drawbacks associated with cytotoxic
  chemotherapy
• At the present time, tyrosine kinase inhibitors serve
  more as second- or third-line therapies rather than
  as primary therapy.
• For the tyrosine kinase inhibitors to have a primary
  role in therapy, there has to be a clear hypothesis
  for their use, relevant preclinical data, and a
  demonstrated use in well characterized groups of
  patients
R e rec s
  fe ne
REFERENCES
1. Goodman & Gilman’s The Pharmacological Basis
   of THERAPEUTICS. Twelfth edition: pg 1731-
   1740
2. Bertram G,Katzung,Basic & Clinical Pharmacology,
   eleventh edition: pg 953-955.
3. Charles R.Craige, Robert E.Stitzel: MODERN
   PHARMACOLOGY with Clinical applications.pg
   653.
4. Lippincott’s Illustrated Reviews:Pharmacology 5th
   edition:pg 509-511.
REVIEW ARTICLES

1. Amit Arora and Eric M: “Role of Tyrosine Kinase
   Inhibitors in Cancer Therapy”, THE JOURNAL
   OF PHARMACOLOGY AND EXPERIMENTAL
   THERAPEUTICS [JPET] 315:971–979, 2005.
2. Jianming Zhang- “Targeting cancer with small
   molecule kinase inhibitors”: Nature Rev. Drug
   Discov January 2009 | Volume 9: 28-39.
Drug Interactions
Strong CYP3A4 Inhibitors
ketoconazole, itraconazole, voriconazole,
  posiconazole
clarithromycin, telithromycin
atazanavir, indinavir, nelfinavir, ritonavir, saquinavir,
nefazodone

Moderate CYP3A4 Inhibitors
fluconazole, erythromycin, aprepitant, grapefruit
   juice,
verapamil, cimetidine
Drug Interactions
• CYP3A4 Inducers
Barbiturates, carbamazepine, phenytoin
glucocorticoids
rifampin, rifabutin
nevirapine, efavirenz
troglitazone, pioglitozone
St. John’s Wort
ERLOTINIB
• Dosage adjustment
• Dosage adjustment for patients with
  hepatic impairment
     • None recommended → monitor for potential side
       effects because of significant liver metabolism
• Dosage adjustment for patients with renal
  impairment
     • None recommended

TYROSINE KINASE INHIBITORS

  • 1.
    TYROSINE KINASE INHIBITORS PRESENTED BY: Y.VIJAY FINAL YEAR POST GRADUATE DEPARTMENT OF PHARMACOLOGY OSMANIA MEDICAL COLLEGE
  • 2.
    CONTENTS • INTRODUCTION • TYPESOF TYROSINE KINASES • ROLE OF KINASES IN SIGNALLING PATHWAYS • DRUGS TARGETTING TYROSINE KINASES • CONCLUSION • REFERECES
  • 3.
    INTRODUCTION • PROTEIN KINASES: •Protein kinases are a group of enzymes that possess a catalytic subunit that transfers the gamma (terminal)phosphate from nucleotide triphosphates (often ATP) to one or more amino acid residues in a protein substrate side chain, resulting in a conformational change affecting protein function.
  • 4.
    CATEGORIES OF PROTEINKINASES • Classified into three different categories: 1. Kinases that specifically phosphorylate tyrosine residues 2. Kinases that phosphorylate serine and threonine residues, and 3. Kinases with activity toward all three residues.
  • 5.
    TYPES OF TYROSINEKINASES • Tyrosine kinases can be further subdivided into 1. Receptor tyrosine kinases eg: EGFR, PDGFR, FGFR 2. Non-receptor tyrosine kinases eg: SRC, ABL, FAK and Janus kinase
  • 6.
    T Y OSIN KI N R E ASE ST R U T U E C R Extracellular Domain Transmembrane Domain TK Intracellular Domain
  • 7.
    RTK structure/function Regulatory domains
  • 8.
    Oncogenic activation ofTyrosine kinase • Normally the level of cellular tyrosine kinase phosphorylation is tightly controlled by the antagonizing effect of tyrosine kinase and tyrosine phosphatases. • Some Common mechaninsms of oncogenic activation: 1. Activation by mutation 2. BCR-ABL and human leukemia
  • 9.
    TYROSINE KINASE INIBITORS 1.BCR-ABL Tyrosine Kinase Inhibitors eg: Imatinib Mesylate, Dasatinib, and Nilotinib. 2. Epidermal Growth Factor Receptor TyrosineKinase Inhibitors eg: Gefitinib, Lapatinib. 3. Vascular Endothelial Growth Factor TyrosineKinase Inhibitors eg. Semaxinib, Vatalanib, Sunitinib, Sorafenib.
  • 10.
    BCR-ABL Tyrosine KinaseInhibitors • Mechanism of action : • IMATINIB & NILOTINIB: bind to a segment of the kinase domain that fixes the enzyme in a closed or nonfunctional state, in which the protein is unable to bind its substrate/phosphate donor, ATP. • DASATINIB: binds both the open and closed configuration of BCR-ABL kinase.
  • 11.
    BCR-ABL Tyrosine KinaseInhibitors • PHARMACOKINETICS 0f Imatinib / Dasatinib • Absorption – Oral bioavailability ~ 98% • Distribution – highly protein bound • Metabolism - Primarily by CYP3A4 • Elimination – Fecal ~ 65-80% renal ~ 10-13% – Half life = Imatinib-18 hrs, N-desmethyl derivative- 40 hrs Dasatinib- 3-5 hrs Nilotinib- 17 hrs
  • 12.
    IMATINIB MESYLATE • Firstmolecularly targeted protein kinase inhibitor to receive FDA approval. • It targets the BCR-ABL tyrosine kinase, which underlies chronic myelogenous leukemia (CML). • BCR-ABL tyrosine kinase is present in virtually all patients with chronic myelogenous leukemia (CML) and some patients with acute lymphoblastic leukemia (ALL)
  • 13.
    IMATINIB MESYLATE Dosing and Administration • Treatment of Philadelphia chromosome(+) chronic myelogenous leukemia – Chronic phase, initial therapy • 400 mg PO once daily - continue as long as the patient continues to benefit • May increase to 600 mg PO once daily – Accelerated phase or blast crisis • 600 mg PO once daily - continue as long as the patient continues to benefit • May increase to 800 mg/day PO
  • 14.
    IMATINIB MESYLATE • Toxicity •Gastrointestinal – Nausea, vomiting, abdominal pain • Edema – Periorbital edema or peripheral edema in the lower extremities • Diarrhea • Muscle cramps • Fatigue • Skin rash • Cytopenias
  • 15.
    Imatinib (Gleevec®) FDA Approved Indications • Chronic Myeloid Leukemia • Pediatric CML • Acute Lymphoblastic Leukemia • Gastrointestinal Stromal Tumors • Myelodysplastic/Myeloproliferative Diseases • Aggressive Systemic Mastocytosis • Hypereosinophilic Syndrome/Chronic Eosinophilic Leukemia • Dermatofibrosarcoma Protuberans
  • 16.
    DASATINIB • Multi-kinase inhibitor •BCR-ABL, SRC family, c-KIT, EPHA2, PDGFRβ • FDA Approved Indications – Treatment of adults with chronic, accelerated, or myeloid or lymphoid blast phase CML – Treatment of adults with Philadelphia- chromosome (+) ALL with resistance or intolerance to prior therapy
  • 17.
    NILOTINIB • Indication: treatmentof chronic phase and accelerated phase Philadelphia chromosome positive chronic myelogenous leukemia (CML) in adult patients resistant to or intolerant to prior therapy that included imatinib.
  • 18.
    NILOTINIB • Pharmacokinetics • Absorption – Peak plasma levels – 3 hours – Approximately 30% of an oral dose of Nilotinib is absorbed after administration – Food (fatty meal) increases absorption • Distribution – Highly protein bound – Plasma concentrations reach a steady state only after 8 days of daily dosing
  • 19.
    NILOTINIB Toxicities • Thrombocytopenia andNeutropenia • QT-prolongation – with sudden death reported • Liver function abnormality – elevated bilirubin,AST/ALT and alkaline phosphatase • Electrolyte abnormality ( hyper and hypo K, hypo Mg, Phos, Ca, Na)
  • 20.
    Mechanism of resistanceto Bcr-Abl kinase inhibitors • POINT MUTATIONS CONTACT POINTS BETWEEN Imatinib and the enzyme become the sites of mutation. • Amplification of Wild type of Kinase gene • Philadelphia –ve clones.
  • 21.
    Epidermal Growth FactorReceptor TyrosineKinase Inhibitors • Gefitinib, • Erlotinb • Lapatinib
  • 22.
    Epidermal Growth FactorReceptor TyrosineKinase Inhibitors • Mechanism of Action of Gefitinib / Erlotinib Inhibit the EGFR tyrosine kinase by virtue of competitive blockade of ATP binding • Selectively inhibits EGFR-TK Blockage of downstream EGFR signal transduction pathways, cell cycle arrest, and inhibition of angiogenesis
  • 23.
    Epidermal Growth FactorReceptor TyrosineKinase Inhibitors • Pharmacokinetics of Gefitinib / Erlotinib Absorption – Peak plasma levels occurs 3-7 hours after dosing – Mean bioavailability of 60% – H2 Blockers and Proton pump inhibitors reduce plasma concentrations. Distribution – 90% protein bound Metabolism – Predominantly via CYP3A4 Elimination – Half life – Gefitinib- 48 hrs, Erlotinib- 36 hrs – Fecal 86%, renal elimination < 4%
  • 24.
    GEFITINIB • Toxicities • Dermatologic – Rash, acne, xerosis, pruritus • Gastrointestinal – Diarrhea, Nausea, vomiting, anorexia • Ocular – Pain and corneal erosion/ulcer, aberrant eyelash growth
  • 25.
    GEFITINIB Toxicities • Pulmonary – Interstitial lung disease, consisting of interstitial pneumonia, pneumonitis, and alveolitis – In the event of acute onset or worsening of pulmonary symptoms (e.g., dyspnea, cough, fever), gefitinib treatment should be interrupted and the symptoms promptly investigated – If interstitial lung disease is confirmed, gefitinib therapy should be discontinued
  • 26.
    GEFITINIB • Drug Interactions •CYP 3A4 inducers and inhibitors • Warfarin: reports of elevations in INR values and/or bleeding events – Monitor INR regularly • H2-blockers and proton pump inhibitors: may ↓ plasma concentrations – May potentially reduce Gefitinib efficacy
  • 27.
    GEFITINIB INDICATIONS • Non-small Cell Lung Cancer (NSCLC) Monotherapy for continued treatment of locally advanced or metastatic NSCLC after failure of both platinum-based and Docetaxel regimens • PRESENT INDICATION: NSCLC – patient’s with proven response prior to FDA “withdrawal” of approval or on a clinical trial
  • 28.
    ERLOTINIB It is aQuinazolinamine inhibitor of HER1/EGFR tyrosine kinase. INDICATIONS – approved for second-line treatment of patients with locally advanced or metastatic non–small cell lung cancer. – Erlotinib also is approved for first-line treatment of patients with locally advanced, unresectable, or metastatic pancreatic cancer in combination with Gemcitabine. Unlabeled Uses – Treatment of Squamous cell head and neck cancer
  • 29.
    ERLOTINIB Mechanism of Action: •Blockage of downstream EGFR signal transduction pathways, cell cycle arrest, and inhibition of angiogenesis • Erlotinib competitively inhibits ATP binding at the active site of the kinase
  • 30.
    ERLOTINIB ADVERSE DRUG REACTIONS • Pulmonary (not life-threatening) – Dyspnea – cough (33%) • Rash (75%) – Median time to onset 8 days (2-14 days) • Gastrointestinal – Diarrhea (54%, onset ≈12 days) – anorexia , – nausea/vomiting (33%/23%) • Fatigue (52%)
  • 31.
    ERLOTINIB ADVERSEDRUG REACTIONS • Ocular – Irritation, conjunctivitis (12%) and keratoconjunctivitis sicca (12%), corneal ulcerations; reports of NCI CTC grade 3 conjunctivitis and keratitis • Hepatotoxicity – Asymptomatic ↑ in liver enzymes, including hyperbilirubinemia • Bleeding events – Gastrointestinal bleeds, elevations in INR values in patients receiving concomitant warfarin administration
  • 32.
    LAPATINIB • LAPTINIB isa 4-anilinoquinazoline kinase inhibitor of the intracellular tyrosine kinase domains of both EGFR and HER2 receptors • Mechanism of Action Lapatinib and other pan-HER inhibitors block both ErbB1 and ErbB2 and bind to an internal site on the receptor (usually the ATP-binding pocket) • It also binds to inhibits a truncated form of HER2 receptor that lacks a Trastuzumab binding domain.
  • 33.
    LAPATINIB • INDICATION: • MetastaticBreast Cancer in combination with Capecitabine in patients whose tumors overexpress HER2 and who have received prior therapy including an Anthracycline, a Taxane, and Trastuzumab
  • 34.
    LAPATINIB • Pharmacokinetics • Absorption – Peak plasma levels – 4 hours – Food increases absorption • Distribution – Highly protein bound • Metabolism – Extensive metabolism via CYP3A4, CYP3A5 • Elimination – Half-life = 24 hours – Hepatic metabolism
  • 35.
    LAPATINIB • Dosage andAdministration • Dosage Forms – 250 mg tablets • Administration – In combination with Capecitabine, for the treatment of advanced or metastatic breast cancer which overexpresses HER2 and have received prior therapy including an Anthracycline, a Taxane, and Trastuzumab. – 1250mg (5 tabs) PO once daily, Days 1-21 on an empty stomach
  • 36.
    LAPATINIB • Dosage adjustment •Renal – No adjustments. • Hepatic – Severe impairment: dose reduction to 750mg/day should be considered • Cardiac – Therapy should be stopped for: • > Grade 2 LVEF dysfunction • LVEF less than lower limit of normal
  • 37.
    LAPATINIB • Toxicities When combinedwith Capecitabine • Diarrhea • Palmar-plantar erythrodysesthesia • Nausea/vomiting • Rash • Fatigue • Decreases in LVEF • ECG changes
  • 38.
    Vascular Endothelial Growth FactorTyrosineKinase Inhibitors 1. Semaxinib [with drawn] 2. Vatalanib, 3. Sunitinib, 4. Sorafenib.
  • 39.
    SUNITINIB • Mechanism ofAction • Inhibitor of multiple receptor tyrosine kinases, some of which are implicated in tumor growth, pathologic angiogenesis, and metastatic progression of cancer. • competitively inhibits the binding of ATP to the tyrosine kinase domain on the VEGF receptor-2
  • 40.
    SUNITINIB • Pharmacokinetics • Absorption – Peak plasma levels occur 6-12 hours after dosing – Food has no effect on bioavailability • Distribution – 90 - 95% protein bound • Metabolism – Predominantly via CYP3A4
  • 41.
    SUNITINIB • Pharmacokinetics • Sunitinibis metabolized by CYP3A4 to produce an active metabolite SU12662 • the t1/2 of which is 80-110 hours • steady-state levels of the metabolite are reached after ~2 weeks of repeated administration of the parent drug. • The pharmacokinetics of Sunitinib are not affected by food intake.
  • 42.
    SUNITINIB • Pharmacokinetics • Elimination – Primarily via feces (61%) – 16% renal elimination – Half life: Parent compound (40-60hrs), active metabolite (80-110hrs)
  • 43.
    SUNITINIB • Dosage andAdministration • Dosage Forms – 12.5 mg, 25 mg, 50 mg capsules • Administration – Oral, with or without food • Dosing – For advanced RCC and GIST • 50 mg PO once daily, on a schedule of 4 weeks on treatment followed by 2 weeks off
  • 44.
    SUNITINIB Toxicities • QT-prolongation • Left Ventricular Dysfunction • Hemorrhagic Events • Hypertension (30%) • Hypothyroidism – baseline thyroid function and monitor for signs
  • 45.
    SUNITINIB Toxicities • Adrenal Insufficiency • GI distress – Diarrhea, nausea, vomiting, stomatitis, dyspepsia • Skin discoloration • Fatigue
  • 46.
    SORAFENIB Mechanism of Action •Multi-kinase inhibitor • Targets RAF/MEK/ERK signaling pathway to inhibit cell proliferation • Inhibits the VEGFR-2/PDGFR-β signaling cascade to inhibit angiogenesis
  • 47.
    SORAFENIB Pharmacokinetics • Absorption – Peak plasma levels achieved in ~3 hours – Food reduced bioavailability by ~29% • Distribution – Protein binding 99.5%
  • 48.
    SORAFENIB Pharmacokinetics • Metabolism – Primarily by CYP3A4 – Eight metabolites identified – Pyridine N-oxide has shown in vitro potency similar to the parent drug. • Excretion – 77% Feces – 19% Urine
  • 49.
    SORAFENIB Toxicities • Hand-foot syndrome, alopecia, rash • Diarrhea or constipation • Nausea/vomiting, abdominal pain • Fatigue • High blood pressure • Bleeding • Neuropathy, joint pain • Dyspnea
  • 50.
    VATALANIB • Small moleculeprotein kinase inhibitor that inhibits angiogenesis • It inhibits all known VEGF receptors, as well as platelet-derived growth factor receptor-beta and c-kit. • Most selective for VEGFR-2.
  • 51.
    VATALANIB • Itis being studied as a single agent and in combination with chemotherapy in patients with 1. Colorectal cancer and liver metastases, 2. Advanced prostate cancer 3. Renal cell cancer 4. Relapsed/refractory Glioblastoma multiforme.
  • 52.
    SUMMARY • Targeted therapyprovides a new approach for cancer therapy that has the potential for avoiding some of the drawbacks associated with cytotoxic chemotherapy • At the present time, tyrosine kinase inhibitors serve more as second- or third-line therapies rather than as primary therapy. • For the tyrosine kinase inhibitors to have a primary role in therapy, there has to be a clear hypothesis for their use, relevant preclinical data, and a demonstrated use in well characterized groups of patients
  • 53.
    R e recs fe ne
  • 54.
    REFERENCES 1. Goodman &Gilman’s The Pharmacological Basis of THERAPEUTICS. Twelfth edition: pg 1731- 1740 2. Bertram G,Katzung,Basic & Clinical Pharmacology, eleventh edition: pg 953-955. 3. Charles R.Craige, Robert E.Stitzel: MODERN PHARMACOLOGY with Clinical applications.pg 653. 4. Lippincott’s Illustrated Reviews:Pharmacology 5th edition:pg 509-511.
  • 55.
    REVIEW ARTICLES 1. AmitArora and Eric M: “Role of Tyrosine Kinase Inhibitors in Cancer Therapy”, THE JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS [JPET] 315:971–979, 2005. 2. Jianming Zhang- “Targeting cancer with small molecule kinase inhibitors”: Nature Rev. Drug Discov January 2009 | Volume 9: 28-39.
  • 59.
    Drug Interactions Strong CYP3A4Inhibitors ketoconazole, itraconazole, voriconazole, posiconazole clarithromycin, telithromycin atazanavir, indinavir, nelfinavir, ritonavir, saquinavir, nefazodone Moderate CYP3A4 Inhibitors fluconazole, erythromycin, aprepitant, grapefruit juice, verapamil, cimetidine
  • 60.
    Drug Interactions • CYP3A4Inducers Barbiturates, carbamazepine, phenytoin glucocorticoids rifampin, rifabutin nevirapine, efavirenz troglitazone, pioglitozone St. John’s Wort
  • 61.
    ERLOTINIB • Dosage adjustment •Dosage adjustment for patients with hepatic impairment • None recommended → monitor for potential side effects because of significant liver metabolism • Dosage adjustment for patients with renal impairment • None recommended