An introduction to biotechnology

Since Amgen’s founding in 1980, the company’s focus has been on discovering, developing, and delivering novel

medicines for patients with serious illnesses. Amgen’s scientists are pioneers in the field of biotechnology, delivering

treatments based on advances in cellular and molecular biology. And Amgen therapies have helped millions of people

worldwide to fight cancer, kidney disease, bone disease, rheumatoid arthritis, and other serious illnesses.

Pioneering science delivers vital medicines

In 1919, Hungarian agricultural engineer Karl Ereky foresaw a time when biology could be used

for turning raw materials into useful products. He coined the term biotechnology to describe

that merging of biology and technology.

Ereky’s vision has now been realized by thousands of companies and research institutions. The

growing list of biotechnology products includes medicines, medical devices, and diagnostics,

as well as more-resilient crops, biofuels, biomaterials, and pollution controls. While the field

of biotechnology is diverse, the focus of this guide is on biotechnology medicines.

How do biotechnology medicines differ from other medicines?

A medicine is a therapeutic substance used for treating, preventing, or curing disease. The

most familiar type of medicine is a chemical compound contained in a pill, tablet, or capsule.

Examples are aspirin and other pain relievers, antibiotics, antidepressants, and blood pressure

drugs. This type of medicine is also known as a small molecule because the active ingredient

has a chemical structure and a size that are small compared with large, complex molecules

like proteins. A medicine can be made by chemists in a lab. Most medicines of this type can

be taken by mouth in solid or liquid form.

What is biotechnology?

Biotechnology medicines, often referred to as biotech medicines, are large molecules that are

similar or identical to the proteins and other complex substances that the body relies on to stay

healthy. They are too large and too intricate to make using chemistry alone. Instead, they are made

using living factories—microbes or cell lines—that are genetically modified to produce the desired

molecule. A biotech medicine must be injected or infused into the body in order to protect its

complex structure from being broken down by digestion if taken by mouth.

In general, any medicine made with or derived from living organisms is considered a biotech

therapy, or biologic. A few of these therapies, such as insulin and certain vaccines, have been in

use for many decades. Most biologics were developed after the advent of genetic engineering,

which gave rise to the modern biotechnology industry in the 1970s. Amgen was one of the first

companies to realize the new field’s promise and to deliver biologics to patients.

Like pharmaceuticals, biologics cannot be prescribed to patients until their use has been

approved by regulators. For example, in the United States, the Food and Drug Administration

evaluates new medicines. In the European Union, the European Medicines Agency manages

that responsibility. 1

The science of biotechnologyHow does the body make a protein?

Protein production is a multistep process that

includes transcription and translation. During

transcription, the original DNA code for a specific

protein is rewritten onto a molecule called

messenger RNA (mRNA); mRNA has nucleotides

similar to those of DNA. Each successive

grouping of three nucleotides forms a codon,

or code, for one of 20 different amino acids,

which are the building blocks of proteins.

During translation, a cell structure called a

ribosome binds to a ribbon of mRNA. Other

molecules, called transfer RNAs, assemble

a chain of amino acids that matches the

sequence of codons in the mRNA. Short

chains of amino acids are called peptides.

Long chains, called polypeptides, form proteins.

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The molecular structure of DNA—the double helix

Chromosome

DNA

Gene

Biotechnology has been used in a rudimentary form since

ancient brewers began using yeast cultures to make beer. The

breakthrough that laid the groundwork for modern biotechnology

came when the structure of DNA was discovered in the early

1950s. To understand how this insight eventually led to biotech

therapies, it’s helpful to have a basic understanding of DNA’s

central role in health and disease.

What does DNA do?

DNA is a very long and coiled molecule found in the nucleus,

or command center, of a cell. It provides the full blueprint for the

construction and operation of a life-form, be it a microbe, a bird,

or a human. The information in DNA is stored as a code made

up of four basic building blocks, called nucleotides. The order in

which the nucleotides appear is akin to the order of the letters

that spell words and form sentences and stories. In the case of

DNA, the order of nucleotides forms different genes. Each gene

contains the instructions for a specific protein.

With a few exceptions, every cell in an organism holds a complete

copy of that organism’s DNA. The genes in the DNA of a particular

cell can be either active (turned on) or inactive (turned off)

depending on the cell’s function and needs. Once a gene is

activated, the information it holds is used for making, or

“expressing,” the protein for which it codes. Many diseases

result from genes that are improperly turned on or off.

What functions do proteins control?

The amino acids that form a protein interact with each other, and

those complex interactions give each protein its own specific,

three-dimensional structure. That structure in turn determines

how a protein functions and what other molecules it impacts.

Common types of proteins are:

• Enzymes,whichputmoleculestogetherorbreakthemapart.

• Signalingproteins,whichrelaymessagesbetweencells,

and receptors, which receive signals sent via proteins from

other cells.

• Immunesystemproteins,suchasantibodies,whichdefend

against disease and external threats.

• Structuralproteins,whichgiveshapetocellsandorgans.

Given the tremendous variety of functions that proteins perform,

they are sometimes referred to as the workhorse molecules of

life. However, when key proteins are malfunctioning or missing,

the result is often disease of one type or another.

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Illustration is copyrighted material of BioTech Primer, Inc., and is reproduced herein with its permission.

How does genetic engineering work?

Genetic engineering is the cornerstone of modern

biotechnology. It is based on scientific tools, developed

in recent decades, that enable researchers to:

• Identifythegenethatproducestheproteinofinterest.

• CuttheDNAsequencethatcontainsthegenefrom

a sample of DNA.

• Placethegeneintoavector,suchasaplasmid

or bacteriophage.

• UsethevectortocarrythegeneintotheDNA

of the host cells, such as Escherichia coli (E coli)

or mammalian cells grown in culture.

• Inducethecellstoactivatethegeneandproduce

the desired protein.

• Extractandpurifytheproteinfortherapeuticuse.

When segments of DNA are cut and pasted together to form

new sequences, the result is known as recombinant DNA.

When recombinant DNA is inserted into cells, the cells use

this modified blueprint and their own cellular machinery to

make the protein encoded by the recombinant DNA. Cells

that have recombinant DNA are known as genetically

modified or transgenic cells.

• Geneticengineeringallowsscientiststomanufacture

molecules that are too complex to make with chemistry.

This has resulted in important new types of therapies,

such as therapeutic proteins. Therapeutic proteins

include those described below as well as ones that are

used to replace or augment a patient’s naturally occurring

proteins, especially when levels of the natural protein are

low or absent due to disease. They can be used for treating

such diseases as cancer, blood disorders, rheumatoid

arthritis, metabolic diseases, and diseases of the immune

system.

• Monoclonal antibodies are a specific class of

therapeutic proteins designed to target foreign

invaders—or cancer cells—by the immune system.

Therapeutic antibodies can target and inhibit proteins

and other molecules in the body that contribute to

disease.

• Peptibodies are engineered proteins that have

attributes of both peptides and antibodies but that

are distinct from each.

• Vaccines stimulate the immune system to provide

protection, mainly against viruses. Traditional vaccines

use weakened or killed viruses to prime the body

to attack the real virus. Biotechnology can create

recombinant vaccines based on viral genes.

These new modes of treatment give drug developers

more options in determining the best way to counteract a

disease. But biotech research and development (R&D), like

pharmaceutical R&D, is a long and demanding process with

many hurdles that must be cleared to achieve success.

To manipulate cells and DNA, scientists use tools that are borrowed from nature, including:

Restriction enzymes. These naturally occurring enzymes are used as a defense by bacteria to cut up DNA from viruses.

There are hundreds of specific restriction enzymes that researchers use like scissors to snip specific genes from DNA.

DNA ligase. This enzyme is used in nature to repair broken DNA. It can also be used to paste new genes into DNA.

Plasmids. These are circular units of DNA. They can be engineered to carry genes of interest.

Bacteriophages (also known as phages). These are viruses that infect bacteria. Bacteriophages can be engineered to

carry recombinant DNA.

Genetic engineering tools

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The first step in treating any disease is to clarify how the

disease is caused. Many questions must be answered to

arrive at an understanding of what is needed to pursue new

types of treatments.

• Howdoesapersongetthedisease?

• Whichcellsareaffected?

• Isthediseasecausedbygeneticfactors?Ifso,what

genesareturnedonoroffinthediseasedcells?

• Whatproteinsarepresentorabsentindiseasedcells

ascomparedwithhealthycells?

• Ifthediseaseiscausedbyaninfection,howdoesthe

infectiousorganisminteractwiththebody?

In modern labs, sophisticated tools are used for shedding

light on these questions. The tools are designed to uncover the

molecular roots of disease and pinpoint critical differences

between healthy cells and diseased cells. Researchers often

use multiple approaches to create a detailed picture of the

disease process. Once the picture starts to emerge, it can still

take years to learn which of the changes linked to a disease

are most important. Is the change the result of the disease, or

isthediseasetheresultofthechange?Bydeterminingwhich

molecular defects are really behind a disease, scientists can

identify the best targets for new medicines. In some cases,

the best target for the disease may already be addressed

by an existing medicine, and the aim would be to develop a

new drug that offers other advantages. Often, though, drug

discovery aims to provide an entirely new type of therapy by

pursuing a novel target.

Selecting a target

The term target refers to the specific molecule in the body

that a medicine is designed to affect. For example, antibiotics

target specific proteins that are not found in humans but are

critical to the survival of bacteria. Many cholesterol drugs

target enzymes that the body uses to make cholesterol.

Scientists estimate there are about 8,000 therapeutic targets

that might provide a basis for new medicines. Most are

proteins of various types, including enzymes, growth factors,

cell receptors, and cell-signaling molecules. Some targets

are present in excess during disease, so the goal is to block

their activity. This can be done by a medicine that binds to

the target to prevent it from interacting with other molecules

in the body. In other cases, the target protein is deficient or

missing, and the goal is to enhance or replace it in order to

restore healthy function. Biotechnology has made it possible

to create therapies that are similar or identical to the complex

molecules the body relies on to remain healthy.

The amazing complexity of human biology makes it a

challenge to choose good targets. It can take many years

of research and clinical trials to learn that a new target

won’t provide the desired results. To reduce that risk,

scientists try to prove the value of targets through research

How are biotechnology medicines discovered and developed?

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experiments that show the target’s role in the disease

process. The goal is to show that the activity of the target

is driving the course of the disease.

Selecting a drug

Once the target has been set, the next step is to identify a drug

that impacts the target in the desired way. If researchers decide

to use a chemical compound, a technology called drug screening

is typically used. With automated systems, scientists can rapidly

test thousands of compounds to see which ones interfere with the

target’s activity. Potent compounds can be put through added tests

to find a lead compound with the best potential to become a drug.

In contrast, biologics are designed using genetic engineering. If

the goal is to provide a missing or deficient protein, the gene for

that protein is used for making a recombinant version of the

protein to give to patients. If the goal is to block the target

protein with an antibody, one common approach is to expose

transgenic mice to the target so as to induce their immune

systems to make antibodies to that protein. The cells that

produce these specific antibodies are then extracted and

manipulated to create a new cell line. The mice used in this

process are genetically modified to make human antibodies,

which reduces the risk of allergic reactions in patients.

Developing the drug

Once a promising test drug has been identified, it must go

through extensive testing before it can be studied in humans.

Many drug safety studies are performed using cell lines

engineered to express the genes that are often responsible

for side effects. Cell line models have decreased the number

of animals needed for testing and have helped accelerate the

drug development process. Some animal tests are still required

to ensure that the drug doesn’t interfere with the complex

biological functions that are found only in higher life-forms.

Models for studying disease

The following tools help researchers gain insights into how disease develops.

Cell cultures. By growing both diseased and healthy cells in cell cultures, researchers can study differences in cellular

processes and protein expression.

Cross-species studies. Genes and proteins found in humans may also be found in other species. The functions of many

human genes have been revealed by studying parallel genes in other organisms.

Bioinformatics. The scientific community generates huge volumes of biological data daily. Bioinformatics helps organize that

data to form a clearer picture of the activity of normal and diseased cells.

Biomarkers. These are substances, often proteins, that can be used for measuring a biological function, identifying a disease

process, or determining responses to a therapy. They also can be used for diagnosis, for prognosis, and for guiding treatment.

Proteomics. Proteomics is the study of protein activity within a given cell, tissue or organism. Changes in protein activity can

shed light on the disease process and the impact of medicines under study.

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If a test drug has no serious safety issues in preclinical studies,

researchers can ask for regulatory permission to do clinical

trials in humans. There are three phases of clinical research,

and a drug must meet success criteria at each phase before

moving on to the next one.

Phase 1. Tests in 20 to 80 healthy volunteers and, sometimes,

patients. The main goals are to assess safety and tolerability

and explore how the drug behaves in the body (how long it

stays in the body, how much of the drug reaches its target, etc.).

Phase 2. Studies in about 100 to 300 patients. The goals

are to evaluate whether the drug appears effective, to further

explore its safety, and to determine the best dose.

Phase 3. Large studies involving 500 to 5,000 or more

patients, depending on the disease and the study design.

Very large trials are often needed to determine whether

a drug can prevent bad health outcomes. The goal is to

compare the effectiveness, safety, and tolerability of the

test drug with another drug or a placebo.

If the test drug shows clear benefits and acceptable risks

in phase 3, the company can file an application requesting

regulatory approval to market the drug. In the United States,

the Food and Drug Administration evaluates new medicines.

In the European Union, the European Medicines Agency

manages that responsibility. Regulators review data from

all studies and decide whether the medicine’s benefits

outweigh any risks it may have. If the medicine is approved,

regulators may still require a plan to reduce any risk to patients.

A plan to monitor side effects in patients is also required.

A company can continue doing clinical trials on an approved

medicine to see if it works under other specific conditions

or in other groups of patients, and additional trials may also

be required by regulatory agencies. These are known as

phase 4 studies.

The whole drug development process takes 10 to 15 years

to complete on average. Very few test drugs are able to clear

all the hurdles along the way.

A key early decision in drug discovery is whether to pursue a target by using a small-molecule chemical compound or a

large-molecule biologic. Each has its advantages and disadvantages.

Small molecules can be designed to cross cell membranes and enter cells, so they can be used for targets inside cells.

Some may also cross the blood-brain barrier to treat psychiatric illness and other brain diseases. Biologics usually cannot

cross cell membranes or enter the brain. Their use is largely restricted to targets that sit on the cell surface or circulate

outside the cell.

Small molecules often have good specificity for their targets, but therapeutic antibodies tend to have extremely high

specificity. Most large molecules stay in the body longer, resulting in the need for less frequent dosing.

The right tool for the target

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How are biotechnology medicines made?

The manufacture of biologics is a highly demanding process.

Protein-based therapies have structures that are far larger, more

complex, and more variable than the structure of drugs based on

chemical compounds. Plus, protein-based drugs are made using

intricate living systems that require very precise conditions in order

to make consistent products. The manufacturing process consists

of the following four main steps:

1. Producing the master cell line containing the gene that makes

the desired protein

2. Growing large numbers of cells that produce the protein

3. Isolating and purifying the protein

4. Preparing the biologic for use by patients

Some biologics can be made using common bacteria, such as E coli.

Others require cell lines taken from mammals, such as hamsters.

This is because many proteins have structural features that only

mammalian cells can create. For example, certain proteins have

sugar molecules attached to them, and they don’t function properly

if those sugar molecules are not present in the correct pattern.

Maintaining the right growth environment

The manufacturing process begins with cell culture, or cells grown

in the laboratory. Cells are initially placed in petri dishes or flasks

containing a liquid broth with the nutrients that cells require for

growth. During the scale-up process, the cells are sequentially

transferred to larger and larger vessels, called bioreactors. Some

bioreactor tanks used in manufacturing hold 20,000 liters of cells

and growth media.

At every step of this process, it is crucial to maintain the specific

environment that cells need in order to thrive. Even subtle changes

can affect the cells and alter the proteins they produce. For

that reason, strict controls are needed to ensure the quality and

consistency of the final product. Scientists carefully monitor such

variables as temperature, pH, nutrient concentration, and oxygen

levels. They also run frequent tests to guard against contamination

from bacteria, yeast, and other microorganisms.

When the growth process is done, the desired protein is isolated

from the cells and the growth media. Various filtering technologies

are used to isolate and purify the proteins based on their size,

molecular weight, and electrical charge. The purified protein is

typically mixed with a sterile solution that can be injected or infused.

The final steps are to fill vials or syringes with individual doses of

the finished drug and to label the vials or syringes, package them,

and make them available to physicians and patients.

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Biotechnology is still a relatively new field with great potential for driving medical progress.

Much of that progress is likely to result from advances in personalized medicine. This new

treatment paradigm aims to ensure that patients get the therapies best suited to their specific

conditions, genetic makeups, and other health characteristics.

For example, a new discipline called pharmacogenomics seeks to determine how a patient’s

genetic profile affects his/her responses to particular medicines. The goal is to develop tests

that will predict which patient genetic profiles are mostly likely to benefit from a given medicine.

This model is sometimes called personalized medicine.

Pharmacogenomics has already changed the way clinical trials are conducted: Genetic data is

routinely collected so that researchers can determine whether different responses to a test medicine

might be explained by genetic factors. The data is kept anonymous to protect patients’ privacy.

Biotechnology is also revolutionizing the diagnosis of diseases caused by genetic factors. New

tests can detect changes in the DNA sequence of genes associated with disease risk and can

predict the likelihood that a patient will develop a disease. Early diagnosis is often the key to

either preventing disease or slowing disease progress through early treatment.

Advances in DNA technology are the keys to pharmacogenomics and personalized medicine.

These developments promise to result in more effective, individualized healthcare and advances

in preventive medicine.

What does the future of biotechnology therapies look like?

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Emerging treatments

Gene therapy involves inserting genes into the cells of patients to replace defective genes with

new, functional genes. The field is still in its experimental stages but has grown greatly since the first

clinical trial in 1990.

Stem cells are unspecialized cells that can mature into different types of functional cells. Stem

cells can be grown in a lab and guided toward the desired cell type and then surgically implanted

into patients. The goal is to replace diseased tissue with new, healthy tissue.

Nanomedicine aims to manipulate molecules and structures on an atomic scale. One example is

the experimental use of nanoshells, or metallic lenses, which convert infrared light into heat energy

to destroy cancer cells.

New drug delivery systems include microscopic particles called microspheres with holes just

large enough to dispense drugs to their targets. Microsphere therapies are available and being

investigated for the treatment of various cancers and diseases.

The practice of medicine has changed dramatically over the years through

pioneering advances in biotechnology research and innovation; and millions

of patients worldwide continue to benefit from therapeutics developed

by companies that are discovering, developing, and delivering innovative

medicines to treat grievous illnesses. As companies continue to develop

medicines that address significant unmet needs, future innovations in

biotechnology research will bring exciting new advances to help millions

more people worldwide.

Looking ahead

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