This document provides an overview of drugs affecting haematopoiesis and recent advances in the field. It begins with an introduction to haematopoiesis and haematopoietic growth factors. It then discusses erythropoiesis-stimulating agents such as erythropoietin and darbepoietin in detail, including their mechanisms of action, preparations, therapeutic uses, monitoring, and side effects. The document also summarizes myeloid growth factors and thrombopoietic growth factors. It concludes with references for further reading.

1. 1
Drugs affecting haematopoiesis and
recent advances
Dr. Swaroopa, 2nd year pg,
Department of Pharmacology,
Rangaraya Medical college.

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PREVIOUSLY ASKED QUESTIONS FROM THIS TOPIC IN UNIVRSITY
EXAMS
1. Erythropoietin.*
2. Darbepoietin.
3. Thrombopoietic growth factors.
4. Myeloid Growth factors.*
5. Pharmacokinetics of oral Iron and Management of Iron over dosage.
6. Sargramostim.
7. Epoetin-alfa.
8. Recombinant Human Thrombopoietin.

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CONTENTS
1. INTODUCTION
2. HAEMATOPOIETIC GROWTH FACTORS
3. ERYTHROPOIESIS-STIMULATING AGENTS
4. MYELOID GROWTH FACTORS
5. THROMBOPOIETIC GROWTH FACTORS
6. IRON DEFICIENCY & OTHER HYPOCHROMIC ANAEMIAS
7. RECENT ADVANCES
8. CONCLUSION
9. REFERENCES

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INTRODUCTION
The production and development of all types of blood cells is known as
haematopoiesis.
Hematopoietic stem cells are rare marrow cells that manifest self-renewal and
lineage commitment, resulting in cells which differentiate into 10 or more distinct
blood cell lineages.
This process occurs in the marrow cavities of the skull, vertebral bodies, pelvis, and
proximal long bones.
Several hormones and cytokines have been identified and cloned that affect
hematopoiesis permitting their production in quantities sufficient for research and
for therapeutic use.

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Hematopoiesis also requires an adequate supply of minerals (e.g., iron, cobalt,
and copper) and vitamins (e.g., folic acid, vitamin B12, pyridoxine, ascorbic
acid, and riboflavin).
Clinical applications range from the treatment of primary hematologic diseases
(e.g., aplastic anemia, congenital neutropenia) to their use as adjuncts in the
treatment of severe infections and in the management of patients with kidney
failure or those undergoing cancer chemotherapy or marrow transplantation.
 Stem cell differentiation can be described as a series of developmental steps that
produce mixed blood cell lineage colonies, which give rise to large, immature
single-lineage burst forming units (BFUs) and small, mature colony-forming units
(CFUs) for each of the major blood cell types.

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Hematopoietic growth factors can be divided into two groups:
 Multilineage (also called general, early-acting or pleiotropic ) growth factors,
which stimulate multiple lineages.
 Multilineage growth factors include stem cell factor (also called steel factor or
KIT ligand ), interleukin-3 (IL-3), granulocyte-monocyte colony-stimulating factor
(GM-CSF), insulin-like growth factor 1, IL-9, IL-11.
lineage-specific (also called lineage-dominant or late-acting ) growth factors,
which stimulate differentiation and survival of a single lineage.
Include erythropoietin, thrombopoietin.
HEMATOPOIRTIC GROWTH FACTORS
,

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HAEMATOPOIETIC GROWTH FACTORS
• Erythropoietin (EPO)
• Granulocyte-macrophage colony stimulating factor (GM-CSF)
• Granulocyte colony-stimulating Factor
• Interleukins
• Thrombopoietin (TPO, Mpl* ligand)
• Monocyte/macrophage colony stimulating factor
• Stem call factor (SCF, c-kit ligand, steel factor) and FLT3 ligand (FL)
* Mpl – Myeloproliferative leukaemia

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ERYTHROPOIESIS
Pluripotent hematopoietic stem cell(HSCs)
Unipotent hematopoietic stem cell
Proerythroblast
Early normoblast
STAGES OF ERYTHROPOIESIS
IL1, IL6, IL3 (Interleukins)
GM-CSF, G-CSF,
Erythropoietin GM-CSF

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Intermediate normoblast
(haemoglobinization begins)
Late normoblast
(haemoglobinization++
Nuclear disintegration)
Reticulocyte
Haemoglobinization++
Nucleus remains as strains of reticular Element
Erythrocyte
Cont……

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Pathologic Conditions That Stimulate or Inhibit Erythropoiesis
CONDITION MECHANISM
Stimulate Erythropoiesis
• Bleeding
• Hemolysis
• High altitude
• Pulmonary disease
• JAK2-activating mutations in
myeloproliferative disorders
Inhibit Erythropoiesis
• Chronic kidney disease
• Iron, Folate, or vitamin B12 deficiency
• Chronic inflammatory conditions
• Sideroblastic anemia
• Thalassemia
• Malignant infiltration of bone marrow Aplastic anemia,
• pure red cell aplasia
• Drug-induced bone marrow toxicity
Decrease erythroblast differentiation
and erythrocyte production
Decreases erythropoietin synthesis
in kidney
Increase intracellular JAK-STAT
signaling
Induce tissue hypoxia

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ERYTHROPOIESIS –STIMULATING AGENTS (ESA)
 ERYTHROPOIETIN (EPO) :-
Erythropoietic stimulating agent is the term given to a pharmacological
substance that stimulates red blood cell production.
It is the most important regulator of the proliferation of committed erythroid progenitor
(CFU-E) and their immediate progeny.
Is a glycoprotein with a molecular mass of about 30 Kda.
Was the 1st human hematopoietic growth factor to be isolated, purified from the urine
of patients with severe anaemia.

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 Produced mainly by the liver in fetus and by the kidney after birth.
 Endogenous erythropoietin is expressed primarily in peritubular
interstitial cells of kidney.
 After secretion, EPO binds to a receptor on the surface of committed
erythroid progenitors in the marrow.
 EPO also induces release of reticulocytes from the bone marrow.

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 Erythropoiesis is controlled by a feedback system in which a sensor in the
kidney detects changes in oxygen delivery to modulate the erythropoietin
secretion.
 In response to anaemia or hypoxaemia Epo synthesis is rapidly increased by
100 fold or more through an increased rate of transcription of erythropoietin
gene.
serum Epo levels rise & marrow progenitor cell survival, proliferation &
maturation are dramatically stimulated.
 This results in correction of anaemia but this feedback can be disrupted by
kidney disease, marrow damage & deficiency in iron or essential vitamins
like vit B12 , folic acid.

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Preparations:-
1. Recombinant Human Erythropoietin (rHuEpo)
• Epoetin alfa
• Epoetin beta
• Epoetin omega
• Epoetin zeta
These are supplied in single use vials or
syringes containing 500-40,000 units for i.v or
subcutaneous administration.
Epoetin alfa – plasma t1/2 4-8 hr (after i.v administration)
-- administered 3 times a week.
 Epoetin beta (Methoxy polyethylene glycol) – has long half-life.
-- administered as a single i.v dose or single subcut dose at 2 week
or monthly intervals.

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2. Darbepoietin:- • Modified form of Epoetin alfa.
• Heavily glycosylated.
• Has a longer circulatory half-life
than Epoetin alfa.
• Administered weekly.

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THERAPEUTIC USES:-
 ESAs had a significant positive impact for patients with several types of
anaemia and are used routinely in patients with anaemia secondary to
chronic kidney disease (ckd).
1) Anaemia of chronic renal failure:-
Epoetin alfa :-
• Patients with anaemia secondary to ckd are ideal candidates of epoetin-
alfa therapy as the disease represents a true hormone deficiency state.
• Subcutaneous route of administration is preferred over the i.v route
because absorption is slower & the amount of drug required is reduced
by 20%-40%.

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• Stat dose 80-120 units/kg, subcut, 3 times a week.
• Maintenance dose vary from 10 to >300 units/kg with an average dose of
75 units/kg, subcut, 3 times a week.
• * children less than 5yrs of age require a higher dose.
• ** resistance may develop in patients who develop an inflammatory
illness or become iron deficient, so close monitoring of general health and
iron status is essential.

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• Less common causes of resistance include o Occult blood loss
o Folic acid deficiency
o Carnitine deficiency
o Inadequate dialysis
o Aluminium toxicity
o osteitis fibrosa cystica secondary to
hyperparathyroidism
Darbepoietin :- approved for patients who are anaemic secondary to ckd.
 Recommended Stat dose is 0.45 μg/kg administered i.v or subcut once weekly or
0.75 μg/kg administered every 2 weeks, with dose adjustments depending on the
response.

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2) Anaemia in patients with AIDS:-
• Epoetin alfa therapy has been approved for the treatment of HIV-
infected patients especially those on Zidovudine therapy.
• Excellent responses to doses of 100-300 units/kg, subcut, 3 times a week
3) Cancer related Anaemias:-
• Epoetin alfa therapy, 150 units/kg, 3 times a week or 450-600 units/kg
once a week.
• This can reduce the transfusion requirements in patients with cancer
undergoing chemotherapy.

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4) Uses in perioperative patients :-
• Patients undergoing elective orthopedic and cardiac procedures have
been treated with 150–300 units/kg of Epoetin alfa once daily for the 10
days preceding surgery, on the day of surgery, and for 4 days after
surgery.
• As an alternative, 600 units/kg can be given on days 21, 14, and 7
before surgery, with an additional dose on the day of surgery.

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5) Other uses :-
• Epoetin alfa has received
orphan drug status from the
FDA for the treatment of
the anemia of prematurity,
HIV infection, and
myelodysplasia.
• Highly competitive athletes
have used Epoetin alfa to
increase their hemoglobin
levels (“blood doping”) and
improve performance.
• Anaemia of chronic renal failure.
• Anaemia during chemotherapy for cancer.
• Prevention of the anaemia that occurs in
premature infants
• To increase the yield of autologous blood
before blood donation.
• Anaemia of AIDS (exacerbated by
zidovudine).
• Anaemia of chronic inflammatory
conditions such as rheumatoid arthritis.
Clinical uses of Epoetin

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** Recombination therapy in conjugation with adequate iron intake can be
highly effective in a number of anaemias, especially those associated with
poor Erythropoietic response.
Advantage :-
The ESAs consistently improve the haematocrit & Hb level, this eliminate the need
for transfusions and reliably improve quality of life indices.
 In patients treated with ESA
- increase in reticulocyte count --- in 10 days
- increase in Hematocrit & Hb levels ---- in 2 – 6 weeks

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MONITORING:-
Hematocrit should be determined
If Hematocrit increases by more than 4 points in any 2week period, dose
should be decreased.
Dose of Darbepoietin should be decreased if Hb increase exceeds 1g/day in
any 2 week period.(because of association of excessive rate of rise of Hb with
cardiovascular events).
During Haemodialysis, patients receiving Epoetin alfa or Darbepoietin may
require increased anticoagulation.
• Once a week (pts with HIV & Cancer)
• Twice a week (pts with renal failure)

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SIDE EFFECTS :- common for Epoetin-alfa and Darbepoietin
 Most common side effect is aggravation of Hypertension (most often
associated with rapid rise in Hematocrit).
therefore, ESAs should not be used in patients with pre-existing
uncontrolled HTN.
 Hypertensive encephalopathy & seizures seen in patients with chronic
renal failure.
 Headache
 Tachycardia
 Oedema
 Shortness of Breath
 Nausea & Vomiting
 Diarrhoea
 Injection site stinging
 Flu-like symptoms (e.g.. Arthralgias & myalgias)

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MYELOID GROWTH FACTORS
The myeloid growth factors are glycoproteins that stimulate the proliferation and
differentiation of one or more myeloid cell types.
Myeloid growth factors are produced naturally by a number of different cells, including
fibroblasts, endothelial cells, macrophages, and T cell.
Recombinant forms of several growth factors include GM-CSF*, G-CSF,** IL-3***,
M-CSF**** or CSF-1, and stem cell factor (SCF) although only G-CSF and GM-CSF
have found meaningful clinical applications.
*GM-CSF – granulocyte-Macrophage colony-stimulating factor,
**G-CSF – granulocyte colony stimulating factor
***IL – interleukin
****M-CSF – monocyte/macrophage colony stimulating factor

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Granulocyte-macrophage colony-
stimulating factor (GM-CSF)
 Acts synergistically with SCF, IL-1,
IL-3, and IL-6 to stimulate CFU-GM
and CFU-Meg to increase neutrophil
and monocyte production.
 With EPO may promote BFU-E
formation.
 Enhances migration, phagocytosis,
superoxide production, and antibody-
dependent cell-mediated toxicity of
neutrophils, monocytes, and
eosinophils.
 Prevents alveolar proteinosis
 Recombinant human GM-CSF
(Sargramostim)
Granulocyte colony-stimulating
factor (G-CSF)
Stimulates CFU-G to increase
neutrophil production.
Enhances phagocytic and
cytotoxic activities of
neutrophils.
Recombinant human G-CSF,
filgrastim, pegfilgrastim,
lenograstim

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 SARGRAMOSTIM:-
Available as Leukine
It is a recombinant granulocyte-macrophage colony stimulating
factor that is used to stimulate haematopoiesis.
It is used in the recovery of leukocytes following chemotherapy.
MOA:-
• Sargramostim, a colony stimulating factor stimulates the proliferation,
differentiation & functional activity of neutrophils & monocytes.
GM-CSF

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Onset of action:-
• Increase in WBC in 7 to 14 days
Duration :-
• WBCs return to baseline within 1-2 weeks of discontinuing the drug
Bioavailability:-
• Subcutaneous administration 75% (compared to i.v)
 SARGRAMOSTIM:-

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 SARGRAMOSTIM:-
Half-life Elimination:-
• Children( 6months– 15yrs)
i.v – 1.5 hrs (range 0.9 to 2.5 hrs)
subcut – 2.3 hrs (0.3 to 3.8 hrs)
• Adults i.v – 3.8 hrs
subcut – 1.4 hrs
Time to peak, serum:-
• IV – during or immediately after infusion
• Subcut – 2.5 to 4 hrs.

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 SARGRAMOSTIM:-
 In the treatment of Acute myeloid
leukemia (following induction
chemotherapy)
IV: 250 mcg/m²/day (infused over 4
hours) starting approximately on day
11 or 4 days after completion of
induction chemotherapy
USES DOSES
 In the treatment of Allogeneic
bone marrow transplantation
(myeloid reconstitution):
IV: 250 mcg/m²/day (infused over 2
hours), begin 2 to 4 hours after the
marrow infusion and at least 24 hours
after chemotherapy or radiotherapy
In the treatment of Allogeneic or
autologous bone marrow
transplantation (treatment of
delayed neutrophil recovery or graft
failure)
IV: 250 mcg/m²/day (infused over 2
hours) for 14 days; If engraftment has
not occurred after 7 days off
Sargramostim, may repeat.

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 SARGRAMOSTIM:-
USES DOSES
 In the treatment of Autologous
peripheral blood progenitor cell
mobilization and collection
IV, Subcut: 250 mcg/m²/day IV (infused
over 24 hours) or Subcut once daily
 In the treatment of Autologous
peripheral blood progenitor cell
transplantation (myeloid
reconstitution)
IV, Subcut: 250 mcg/m²/day IV (infused
over 24 hours) or Subcut once daily
beginning immediately following
infusion of progenitor cells
 In the treatment of Autologous bone
marrow transplantation (myeloid
reconstitution)
IV: 250 mcg/m²/day (infused over 2
hours), begin 2 to 4 hours after the
marrow infusion and at least 24 hours
after chemotherapy or radiotherapy

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 SARGRAMOSTIM:-
USES DOSES
In the treatment of Hematopoietic
radiation injury syndrome (acute)
Subcut: Adults >40 kg: 7 mcg/kg once
daily
In the treatment of Primary
prophylaxis of neutropenia in
patients receiving chemotherapy
(outside transplant and AML) or who
are at high risk for neutropenic fever
(off-label):
Subcut: 250 mcg/m²/day beginning at
least 24 hours after chemotherapy
administration; continue until ANC
>1,500/mm³ for 3 consecutive days

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 SARGRAMOSTIM:-
 In the treatment of acute hematopoietic radiation injury syndrome:
 Weight-directed dosing:
o Infants, Children, and Adolescents:
 Start as soon as possible after suspected or confirmed exposure to radiation
doses >2 gray (Gy);
 do not delay Sargramostim if CBC is not readily available;
 <15 kg:
 Subcut: 12 mcg/kg once daily
 15 to 40 kg:
 Subcut: 10 mcg/kg once daily
 >40 kg:
 Subcut: 7 mcg/kg once daily

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 SARGRAMOSTIM:- Side Effects :-
Cardiovascular
• Hypertension
• Edema
• Pericardial
Effusion
• Chest Pain
• Peripheral
• Edema
• Tachycardia
Central Nervous
System
• Malaise
• Headache
• Chills
• Anxiety
• Insomnia
Dermatologic
• Skin Changes
• Skin Rash
• Pruritus
Endocrine & Metabolic
• Elevated Serum
Glucose
• Weight Loss
• Decreased Serum
Albumin
• Hyperglycaemia
• Hypomagnesemia
Gastrointestinal
• Diarrhea
• Nausea
• Vomiting
• Abdominal Pain
• Anorexia
• Hematemesis
• Dysphagia
• Gastrointestinal
Hemorrhage
Genitourinary
• Urinary Tract
Infection
Hepatic
• Hyperbilirubinemia
Neuromuscular & Skeletal:
• Asthenia
• Ostealgia
• Arthralgia
• Myalgia
Ophthalmic
• Retinal Hemorrhage
Renal:
• Increased Serum
Creatinine
Respiratory:
• Pharyngitis
• Epistaxis
• Dyspnea
Miscellaneous:
• Fever
• Laboratory Test
Abnormality

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 SARGRAMOSTIM:- Warnings and precautions:
• previous cardiac arrhythmia
• Edema, capillary leak syndrome and pleural effusion.
• Hypersensitivity: Severe allergic and anaphylactic reactions were observed
• Immunogenicity: Sargramostim treatment may result in neutralizing anti-drug
antibody
• Infusion reactions: symptoms include respiratory distress and hypoxia, flushing,
hypotension and/or syncope.
• Leucocytosis : With Sargramostim, white blood cell counts exceeding 50,000/mm
were reported

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 SARGRAMOSTIM:-
Monitoring parameters:
 CBC with differential (twice weekly during treatment); when monitoring for
hematopoietic radiation injury syndrome, obtain CBCs every 3 days.
 vital signs.
 hydration status.
 weight.
 monitor for signs/symptoms of hypersensitivity or infusion-related reactions

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 FILGRASTIM (NEUPOGEN) :
Filgrastim (Neupogen) and biosimilars of Filgrastim is a recombinant non-
pegylated granulocyte colony-stimulating factor used in patients with
neutropenia.
Filgrastim and Biosimilar Uses:
 Chemotherapy-induced myelosuppression in non-myeloid malignancies:
 Acute myeloid leukemia (AML) following induction or consolidation
chemotherapy.
G-CSF

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 Bone marrow transplantation (Neupogen and filgrastim biosimilars)
 Hematopoietic radiation injury syndrome, acute (Neupogen only)
 Peripheral blood progenitor cell collection and therapy (Neupogen and
filgrastim biosimilars)
 Severe chronic neutropenia (Neupogen and filgrastim biosimilars)

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MOA of Filgrastim (Neupogen):
 Filgrastim, a granulocyte-colony-stimulating factors (G-CSF), is produced using
recombinant DNA technology. G-CSFs stimulate the maturation, production, and
activation neutrophils in order to increase their migration and cytotoxicity.
The onset of action:
 Filgrastim: 1 to 2 days
 Tbo-filgrastim: Time to maximum ANC: 3 to 5 days
Duration of action:
 Filgrastim: Neutrophil counts generally return to baseline within 4 days
 Tbo-filgrastim: ANC returned to baseline by 21 days after completion of chemotherapy

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Metabolism:
• Systemically degraded
Bioavailability:
• Filgrastim: Subcut: 60% to 70%; Tbo-filgrastim: Subcut: 33%
Half-life elimination:
• Neonates: 4.4 ± 0.4 hours
• Adults: Filgrastim: ~3.5 hours;
• Tbo-filgrastim: 3 to 3.5 hours
Time to peak serum concentration:
• Subcut: Filgrastim: 2 to 8 hours;
• Tbo-filgrastim: 4 to 6 hours

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Administration of Filgrastim (Neupogen)
 Do not administer earlier than 24 hours after or in the 24 hours prior to cytotoxic
chemotherapy.
 IV (Neupogen and filgrastim biosimilars):
o It can be administered intravenously as a short infusion over 15 to 30 minutes time
(chemotherapy-induced neutropenia)
or
o By continuous infusion (chemotherapy-induced neutropenia)
or
o as an infusion of no longer than 24 hours duration (bone marrow transplantation).

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 Subcutaneous:
o Subcut administration can be done (chemotherapy-induced neutropenia,
peripheral blood progenitor cell collection, severe chronic neutropenia,
hematopoietic radiation injury syndrome).
o Administration can be done into the outer upper arm, abdomen (except within 2
inches of the navel), front middle thigh, or the upper outer buttocks area.
o Change injection site; do not inject into tender, red, bruised, hardened, scaly, or
scarred areas, or sites with stretch marks.

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Off Label Use of Filgrastim in Adults:
o Severe Alcoholic hepatitis
o Anemia in myelodysplastic syndrome
o Hematopoietic stem cell mobilization for collection and subsequent
autologous transplantation in patients with non-Hodgkin lymphoma
or multiple myeloma
o Neutropenia in advanced HIV infection
o Hepatitis C treatment-associated neutropenia.

45. 45
Cardiovascular
o Chest Pain
Central Nervous System
o Fatigue
o Dizziness
o Pain
Dermatologic
o Skin Rash
Gastrointestinal
o Nausea
Common Side Effects of Filgrastim (Neupogen)
Hematologic & Oncologic
o Thrombocytopenia
o Splenomegaly
Hepatic
o Increased Serum Alkaline
Phosphatase
Neuromuscular & Skeletal
o Ostealgia
o Back Pain
Miscellaneous
o Fever
Respiratory
o Epistaxis
o Cough
o Dyspnoea

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THROMBOPOIESIS
 Platelets—sometimes called thrombocytes —are essential for clot formation.
These small cells, which lack a nucleus and do not synthesize new proteins, have
a half -life of about 10 days in the circulation.
 The production of platelets is controlled by both multilineage and lineage-specific
growth factors.
 The most important multilineage growth actors that stimulate platelet production
are IL-11, IL-3, GM-CSF, stem cell actor, and IL-6.
 Differentiation into CFU-Mega cells and then into megakaryocytes (which then
form platelets) is promoted by the lineage-specific growth factor Thrombopoietin.

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THROMBOPOIETIC GROWTH FACTORS
THROMBOPOIETIN:-
 Thrombopoietin (TPO) is produced in the
liver and, to a lesser extent, in the proximal
convoluted tubule of the kidney.
 Thrombopoietin signals through a JAK-
STAT* transduction cascade.
 Circulating levels of Thrombopoietin are regulated by the thrombopoietin
receptor (also known as Mpl )
* Janus Kinase- Signal transducers and Activators of Transcription

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 Structurally and functionally, the thrombopoietin receptor resembles the
receptors or IL-3, erythropoietin, and GM-CSF.
 It is found both on platelet progenitors—CFU-S, CFU-Mix, CFU-Mega, and
megakaryocytes—and on platelets themselves.
• Stimulates the self-renewal and expansion of hematopoietic stem cells.
• Stimulates stem cell differentiation into megakaryocyte progenitors.
• Selectively stimulates megakaryocytopoiesis to increase platelet production.
• Acts synergistically with other growth factors, especially IL-6 and IL-11.
Thrombopoietin (TPO, Mpl ligand) :-

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• A low platelet count, or thrombocytopenia, is an important adverse effect
of many cancer chemotherapeutic agents.
• The complications of thrombocytopenia include increased bleeding risk and platelet
transfusion requirement; in turn, platelet transfusion is associated with an increased
risk of infection, febrile reaction and rarely, graft-versus-host disease.
Agents That Stimulate Platelet Production
• Thrombopoietin (TPO) analogues, Recombinant human thrombopoietin (rhTPO)
and Pegylated recombinant human megakaryocyte growth and development factor
(PEG-rHuMGDF) have the potential to increase megakaryocytopoiesis (platelet
production) in a dose-dependent manner.

50. 50
However, only recombinant human IL-11 (rhIL-11or oprelvekin)
has been approved by the FDA for this indication.
These agents must all be administered prophylactically because
there is a 1–2 week delay rom drug administration to a clinically
significant increase in platelet count.

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Thrombopoietin Receptor Agonists
 Thrombopoietin, a glycoprotein produced by the liver, marrow stromal
cells, and other organs, is the primary regulator of platelet production.
 Two forms of recombinant thrombopoietin have been tested for clinical use.
 One is a truncated version of the native protein, termed recombinant human
megakaryocyte growth and development factor (rHuMGDF).
 The second is the full-length polypeptide termed recombinant human
thrombopoietin (rHuTPO).
 Both will cause a two fold to ten fold increase in platelet count.

52. 52
 PEG-rHuMGDF) were dropped from clinical development because of an excess
risk of developing anti-TPO autoantibodies, which could suppress natural platelet
production.
 The testing of full-length rhTPO was subsequently dropped as well, even though
there were no reports of neutralizing antibodies in patients who received this
lightly bioengineered agent.
Two newer TPO receptor agonists are approved by the FDA for treatment of
thrombocytopenia due to refractory immune thrombocytopenic purpura (ITP) (an
autoimmune disease caused by autoantibodies directed against the patient’s own
platelets). These drugs are Eltrombopag and Romiplostim.

53. 53
*ELTROMBOPAG :-
a small-molecule TPO receptor agonist.
Is administered orally;
The recommended starting dose is 50 mg/d, titrated to 75 mg depending on
platelet response.
By activating the TPO receptor, will induce a transient increase in the platelet
count.

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ROMIPLOSTIM :-
a recombinant IgG1 Fc-peptide fusion protein.
binds and activates the TPO receptor and induces a transient
increase in the platelet count.
Romiplostim is safe and efficacious in patients with ITP.
The drug is administered weekly by subcutaneous injection,
starting with a dose of 1 μg/kg, titrated to a maximum of 10
μg/kg, until the platelet count increases above 50 × 109 /L.

55. 55
INTERLEUKIN-11:-
Interleukin 11 is a cytokine that stimulates hematopoiesis, intestinal epithelial cell
growth, and osteoclastogenesis and inhibits adipogenesis.
IL-11 also enhances megakaryocyte maturation in vitro.
Recombinant human IL-11 (rhIL-11), also called Oprelvekin , is the only drug
currently approved for the prevention of severe thrombocytopenia in patients
receiving myelosuppressive chemotherapy.
Oprelvekin is produced in Escherichia coli.

56. 56
 t1/2 about 7 h, leads to a Thrombopoietic response in 5–9 days when
administered daily to normal subjects.
The drug is administered to patients at 25–50 μg/kg per day subcutaneously.
Oprelvekin is approved for use in patients undergoing chemotherapy for
nonmyeloid malignancies with severe thrombocytopenia.
Recombinant human IL-11, oprelvekin
The major complications of therapy are fluid retention and associated cardiac
symptoms, such as tachycardia, palpitation, edema, and shortness of breath; this
is a significant concern in elderly patients and often requires concomitant
therapy with diuretics. Also reported are blurred vision, injection site rash or
erythema, and paresthesias.

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• Nutrients necessary for haemopoiesis, most importantly:
–iron
– folic acid and vitamin B12
– pyridoxine and vitamin C.
• Depression of the bone marrow, commonly caused by:
–drug toxicity (e.g. anticancer drugs, clozapine)
– exposure to radiation, including radiotherapy
– diseases of the bone marrow (e.g. idiopathic aplastic anaemia, leukaemias)
– reduced production of, or responsiveness to, erythropoietin (e.g. chronic renal
failure, rheumatoid arthritis, AIDS)

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IRON
 Iron exists in the environment largely as ferric oxide, ferric hydroxide,
and polymers.
 In this state, its biological availability is limited unless solubilized by
acid or chelating agents
To treat iron deficiency anaemia, which can be caused by:
• chronic blood loss (e.g. with menorrhagia, hookworm, colon cancer)
• increased demand (e.g. in pregnancy and early infancy)
• inadequate dietary intake (uncommon in developed countries)
• inadequate absorption (e.g. following gastrectomy, or in diseases such as coeliac
disease, where the intestinal mucosa is damaged by an immunologically based
intolerance to the wheat protein gluten).
USES :-

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PHARMACOKINETICS OF IRON
Maximum iron absorption occurs in the duodenum and proximal jejunum
Absorbed mainly in the form of ferrous (Fe+2 ) form.
Ascorbic acid, succinic acid, -SH- group containing amino acids like cysteine
facilitate conversion of Fe+3 to Fe+2 ,thus promote absorption.
Absorption is hindered by coffee, tea, antacids( of Ca, Al & Mg) and phosphates.
Absorbed by active transport across the intestinal mucosa.
Absorption :-

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Storage & Distribution:-
 If the body does not need iron, then the ingested iron gets bound to apoferritin
to make a apoferritin-iron complex called FERRITIN which is the stored in
almost in every cell of the body.
 The rate of iron absorption depends on the ratio of apoferritin and ferritin.
 Fe+3 is stored as Ferritin or as haemosiderin-Fe+3 in reticuloendothelial cells
and some muscle myoglobin, cytochromes and enzymes of parenchymal cells.

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The distribution of iron in the body of a healthy 70 kg man
Protein Tissue Iron content (mg)
Haemoglobin Erythrocytes 2600
Myoglobin Muscle 400
Enzymes Liver and other tissues 25
(cytochromes, catalase,
guanylyl cyclase, etc.)
Transferrin Plasma and extracellular fluid 8
Ferritin and hemosiderin Liver 410
Spleen 48
Bone marrow 300

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Utilization:-
 On body’s demand for iron, transferrin (a transport glycoprotein) enters the
plasma and binds with free Fe+3 or Fe+2 and carries it to the bone marrow for
being used in haemoglobin synthesis.
Excretion :-
Iron is well conserved in the body.
Only 0.5 – 1mg is excreted a daily basis & major elimination is through the faeces
by exfoliation of GIT cells with their intracellular stores of ferritin.
Menstruation causes iron loss to about 1- 2 mg/day.

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TREATMENT OF IRON DEFICIENCY ANAEMIA
Iron preparations can be given orally or parenterally.
Oral Iron Therapy
Most commonly used iron preparation is ferrous sulphate.
Each 100 mg of ferrous sulfate provides 20% of elemental iron.
In adults – a total of 200 mg of elemental iron, daily in 2-3 divided doses
after meals or in between meals.
In children the dose is 3-5 mg/kg to be given in 3 divided doses.
For prophylactic use, 30 mg of elemental iron per day is sufficient.

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Adverse effects of oral iron
• Depend upon the dose(elemental iron content)
• Most common is constipation.
• Others – diarrhoea, epigastric pain, heart burn,
nausea, vomiting, metallic taste and staining of teeth.

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Parenteral iron therapy :-
 Is for those who are unable to tolerate oral iron, pts with acute or chronic
blood loss, GIT disorders like Sprue or inflammatory bowel disease.
 Classical parenteral iron preparation is IRON DEXTRAN (i.v or i.m) 50
mg of elemental iron per ml of the solution.
 Other parenteral preparations : • Iron sucrose complex (i.v or i.m)
• Iron-sodium gluconate (i.v or i.m)
• Iron- sorbital-citric acid complex (only
IM)

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IRON TOXICITY AND TREATMENT ACUTE
CHRONIC
Acute toxicity :-
• Occurs mostly in young children who have ingested a number of iron tablets.
• Fatal dose 15-20 tab of ferrous sulfate.
• Manifestations :- abdominal pain, vomiting, diarrhoea, hematemesis,
cyanosis, dehydration, acidosis, convulsions, shock and death due to
cardiovascular collapse.

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Treatment :-
Desferoxamine, an iron chelator, is a specific antidote.
given slow i.v
 chelate and remove iron has already been absorbed.
 Then excrete in urine and faeces as a chelated complex.
 Removes iron from both ferritin and transferrin.

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Chronic iron toxicity (iron over load):-
• Known as hemochromatosis
• Occurs when excess iron gets deposited in different organs like heart, liver,
kidney and pancreas that can end up in organ failure and death.
Treatment :-
• If Anaemia is not present, it can be managed by intermittent Phlebotomy.
(one unit of blood is removed every week or fortnight till excess iron is dislodged.
Deferiprone or Deferasirox selective iron chelator, can also be used to treat iron
overload in patients with thalassemia. Given orally.

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 Hematopoietic stem cell transplantation (HSCT) is currently an indispensable treatment
for not only incurable blood diseases such as aplastic anemia and severe hemolytic
anemia, but also malignant hematological diseases such as leukemia and lymphoma.
RECENT ADVANCES
Characteristics of HSCs:-
 Generally stem cells are defined as cells capable of self-renewal and
multilineage differentiation.
 In addition to these two characteristics, HSCs have the capability of
cell-cycle dormancy, i.e. to enter a state of dormancy (G0 phase) in the
cell cycle and can continue blood cell production over a lifetime while
protecting themselves from various kinds of stress.

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 Stem cell factor (SCF) and thrombopoietin (TPO) are important direct
cytokine regulators of HSCs.
 Although SCF promotes the proliferation and differentiation of
hematopoietic progenitor cells, it is thought to not be essential for the
initiation of hematopoiesis and HSC self-renewal.
 TPO and its receptor, c-Mpl, are thought to play important roles in early
hematopoiesis from HSCs.

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Hematopoietic stem cell (HSC) surface markers and typical cytokines that regulate HSCs.
Stem cell factor (SCF) promotes the proliferation and differentiation of HSCs. Thrombopoietin
(TPO) and its receptor, c-Mpl, play important roles in early hematopoiesis, especially self-renewal.
Signals from angiotensin-1 via Tie2 and transforming growth factor -β via its receptors regulate
HSC dormancy.

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 While making a HSC with few opportunities for cell division into a
transgenic target, it is important to design a safe and efficient vector for
inserting a gene into the host chromosome.
3. Vectors for HSC gene therapy:
 Vectors derived from the Retroviridae family, RNA viruses with reverse
transcriptase activity, are widely used for inserting genes in host chromosomes.
 Gamma retroviruses and lentiviruses are members of the Retroviridae
family that are commonly used as vectors in HSC gene therapy.

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Genotoxicity of viral vectors:
 The most serious problem with using viral vectors to incorporate a
gene into a chromosome is the potential development of clonal
proliferative diseases such as leukemia.
 Although this problem of genotoxicity represents a great hurdle in the
development of clinical applications for gene therapy, there is
promising ongoing research on the mechanisms underlying
genotoxicity and how to avoid it.

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4. Clinical applications of HSC gene therapy
• Diseases in which gene therapy using HSCs
are being studied.
• They are roughly divided into
hematological disorders,
immunodeficiencies, and metabolic
diseases.
• Most are congenital or hereditary diseases.
• The characteristic clinical features and
recent basic science or clinical studies on
HSC gene therapy for each disease are
Congenital hematopoietic disorders
• β-thalassaemia
Fanconi anemia
Hemophilia
Primary immunodeficiencies
• X-linked severe combined immunodeficiency
(SCID-X1)
Adenosine deaminase deficiency (ADA-SCID)
Chronic granulomatous disease (CGD)
Wiskott-Aldrich syndrome (WAS)
Janus kinase 3 (JAK3) deficiency
Purine nucleoside phosphorylase (PNP)
deficiency
Leukocyte adhesion deficiency type 1 (LAD-1)
Congenital metabolic diseases
• Mucopolysaccharidosis (MPS) types I, II, III,
VII
Gaucher disease
X-linked adrenoleukodystrophy (X-ALD)

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a. Hematopoietic stem cells (HSCs) are
collected from the bone marrow of a patient
with β-thalassemia and maintained them in
culture.
b. Lentiviral-vector particles containing a
functional β-globin gene were then introduced
into the cells and allowed them to expand
further in culture.
c. To eradicate the patient’s remaining HSCs
and make room for the genetically modified
cells, the patient underwent chemotherapy.
d. The genetically modified HSCs were then
transplanted into the patient (Reproduced from
Gene-therapy procedure for patient with b-thalassemia

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CONCLUSION
 with advances in gene introduction technology, such as the development of the SIN vector
and advances in cell or gene-region targeting, gene therapy can be done more safely and
efficiently.
 Furthermore, since cells more immature than HSCs, i.e., iPS(induced pluripotent stem)
cells, are available, further advances in HSC gene therapy are expected in the future.
 The production of cells of the hematopoietic system is controlled by a variety
of proteins called growth factors and cytokines
 Cancer chemotherapy, malignant infiltration of the bone marrow, and other conditions can
cause deficiencies in these cell populations (anemia, neutropenia, and/or thrombocytopenia).
 Preclinical evidence suggests that daily injections of a parathyroid hormone analogue (PTH
1-34) promote blood cell development.
 These observations have led to clinical trials of PTH in enhancing stem cell production or
transplantation and in protecting hematopoietic stem cells from the cytotoxic effects of
chemotherapy.

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 Toshihisa Tsuruta (February 13th 2013). Recent Advances in Hematopoietic Stem Cell
Gene Therapy, Innovations in Stem Cell Transplantation, Taner Demirer, IntechOpen,
DOI: 10.5772/53587. Available from: https://www.intechopen.com/chapters/42648.
 Sharma & Sharma’s, 3rd Edition, Principles of Pharmacology, Haematopoietic Agents,
Vitamins and Antioxidants, chapter10, pg 663- 667
REFERENCES
 Goodman and gilman;13th edition; the pharmacological basis of therapeutics ;
hematopoietic agents: growth factors, minerals, and vitamins; chapter 37; pg no. : 751-
1076.
 David E.Golan, principles of pharmacology, pathophysiologic basis of drug therapy;4th
edition; pharmacology of hematopoiesis and immunomodulation; chapter 45 pg 830-843
 Bertram G.Katzung, A.J.Trevor, basic and clinical pharmacology; 14th edition; agents
used in cytopenia’s; hematopoietic growth factors; chapter 33 pg 591-607.

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THANK YOU