Consumer medicine information


Antithymocyte globulin (equine)


Brand name


Active ingredient

Antithymocyte globulin (equine)




Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Atgam.

What is in this leaflet?

Please read this leaflet carefully before being treated with ATGAM.

This leaflet answers some common questions about ATGAM. It does not contain all the available information and it does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor has weighed the risks of treating you with ATGAM against the expected benefits it will have for you.

Ask your doctor if you have any concerns about being given this medicine.

Keep this leaflet even after your treatment with ATGAM is finished. You may need to read it again.

What ATGAM is used for

ATGAM belongs to a group of medicines called immunosuppressants (anti-rejection medicines).

ATGAM is used in patients who are having a kidney transplant. It helps to stop your body's immune system from rejecting the new kidney.

How ATGAM works

ATGAM works by lowering certain cells within your immune system which are likely to attack your transplanted kidney.

Your doctor may prescribe ATGAM for another purpose.

Ask your doctor if you have any questions about why ATGAM has been prescribed for you.

Before being treated with ATGAM

Always talk to your doctor if you have concerns or questions about your treatment.

When ATGAM must not be used

ATGAM must not be used if you are allergic to equine antithymocyte immunoglobulin or other horse proteins (equine gamma globulins).

ATGAM must not be used if the expiry date (EXP) on the carton or ampoule label has passed. Damaged or leaking ampoules should not be used.

Before treatment with ATGAM

You should only be treated with ATGAM by a doctor who is experienced in giving treatments which reduce your immune response. Treatment should take place in a hospital because of the need for hospital facilities and skilled personnel.

Your doctor will usually give you other medicines when you are given ATGAM. These medicines are also used to reduce your immune response to the new kidney.

It is possible that products developed from horse or human blood can carry infectious diseases like viral hepatitis and AIDS.

You should tell your doctor if:

  • You have previously been treated with ATGAM.

Before being treated with ATGAM, your doctor should do a skin test to see if you are likely to have an allergic reaction to ATGAM.


ATGAM has not been studied in pregnant women. Your doctor will discuss the benefits and risks of using ATGAM in pregnancy.


Do not breastfeed if you are being treated with ATGAM. Ask your doctor if you want more information.


The use of ATGAM in children is limited. It has been used in a small number of children who have had kidney, liver or bone marrow transplants and aplastic anaemia (anaemia due to the absence of bone marrow).

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including any that you buy without a prescription from your pharmacy, supermarket or health food shop.

How ATGAM is given

How ATGAM is given

ATGAM will be given to you by your doctor usually after skin testing. It is diluted and given by slow infusion into a vein over a period of at least 4 hours.

You will be watched all the time in case you have an allergic reaction to ATGAM. If you have an allergic reaction, treatment with ATGAM will be stopped.

You may need to have regular checks for new infections.

How much is given

The recommended dose is 15 mg/kg every day for 14 days. Then on every other day for 14 days. A lower dose may be given in the elderly. In total you will receive ATGAM on 21 days out of 28. Your first dose will usually be given within 24 hours of your kidney transplant, either the day before or the day after.

Your doctor may decide to wait until there are signs that your body is rejecting the new kidney. In this case you will be given 10 to 15 mg/kg ATGAM every day for 14 days. You may then also be given ATGAM every other day for another 14 days. In total you could be given 21 doses of ATGAM.

If you receive too much (overdose)

ATGAM will be given under medical supervision so an overdose is unlikely.

While you are being treated with ATGAM

Things you must do

Keep follow up appointments with your doctor or clinic.

Have any blood tests when your doctor says to. Your doctor may wish to test your response to ATGAM.

Tell any other doctors, dentists, and pharmacists who are treating you that you are being treated with ATGAM.

If you are about to be started on any new medicine tell your doctor, dentist or pharmacist that you are being treated with ATGAM.

Tell your doctor immediately if you become pregnant while being treated with ATGAM.

Things to be careful of

Be careful driving or operating machinery until you know how ATGAM affects you.

Side effects

Tell your doctor or nurse as soon as possible if you do not feel well while you are being treated with ATGAM. ATGAM helps most people who have undergone a kidney transplant but it may have unwanted side effects in some people. All medications can have side effects. Sometimes they are serious, most of the time they are not. Your doctor has weighed the risks of using this medicine against the benefits they expect it will have for you.

Do not be alarmed by this list of side effects. You may not experience any of them.

Very common side effects (occurring in 15% or more of patients):

  • fever, chills, low white blood cell count (which will lower your resistance to infection)
  • blood clotting problems, low platelet count
  • skin rash, itchiness.

Treatment with ATGAM should be stopped if your white blood cell or platelet count drops severely, or you have severe blood clotting problems.

Common side effects (occurring in 1 to 15% of patients):

  • painful joints, chest and/or back pain, pain at the site of injection
  • diarrhoea, nausea, vomiting
  • breathlessness
  • headache
  • slow heart rate, low blood pressure, high blood pressure
  • night sweats
  • blood clots in veins
  • infections
  • sore mouth.

Rare side effects (occurring in less than 1% of patients) that may require immediate medical attention include:

  • severe allergic reaction (anaphylaxis) which may cause any of the following symptoms: shortness of breath, wheezing or difficulty breathing; swelling of the face, lips, tongue or other parts of the body; feeling lightheaded or dizzy; skin rash, itching, hives or redness of the skin; pain in the chest, back or between the ribs and hip.
  • possible inflammation of the brain
  • seizure
  • skin condition where the top layer of skin detaches from the lower layers of the skin all over the body
  • rupture or failure of the kidney.

Some possible side effects of ATGAM, such as abnormal liver or kidney function, can only be detected by your doctor.

Not all side effects are listed here. You may wish to discuss these with your doctor if you are concerned.

Tell your doctor as soon as possible if you experience any side effects, including any effects not listed above.

After treatment with ATGAM


ATGAM will normally be stored in a hospital. It should be stored at 2°C to 8°C and should not be frozen.


The hospital will dispose of used or damaged ampoules of ATGAM.

Product Description

What ATGAM looks like

ATGAM is a sterile, transparent to milky solution which is colourless or faintly pink or brown. It may develop a slight granular or flaky deposit during storage. It is supplied in 5 mL ampoules. Each ampoule is for single use only.


The active ingredient in ATGAM is equine antithymocyte immunoglobulin. There are 250 mg equine antithymocyte immunoglobulin in the 5 mL ampoule.

Other ingredients are glycine, Water for Injections, sodium hydroxide and hydrochloric acid. ATGAM does not contain any preservatives.


Pfizer Australia Pty Ltd
Sydney NSW.
Toll Free Number: 1800 675 229.

This leaflet was prepared in October 2019.

®Registered trademark

Published by MIMS October 2020


Brand name


Active ingredient

Antithymocyte globulin (equine)




1 Name of Medicine

Equine antithymocyte immunoglobulin.

2 Qualitative and Quantitative Composition

Atgam is the purified, concentrated and sterile gamma globulin, primarily monomeric IgG, from hyperimmune serum of horses immunised with human thymus lymphocytes.
Before release for clinical use, each Atgam lot is tested for its ability to inhibit rosette formation between human peripheral lymphocytes and sheep red blood cells in vitro. The potency of lots may vary over a twelve-fold range. The clinical significance of this is unknown.
Atgam is not solely anti-human thymocyte globulin.
Atgam is likely to contain low levels of antibodies against other formed elements of the blood and also other antibodies raised by the horse in response to prior antigenic exposure. These may include pertussis, tetanus, influenza, mycobacterium, equine encephalomyelitis or strangles.
During processing, the drug is adsorbed with human erythrocyte stroma and with IgG-free human plasma proteins to reduce or remove antibodies against human red blood cells and human plasma proteins. Each lot is tested before release to assure that antibody activity against platelets is within acceptable limits. Each lot of Atgam must also test negative for anti-human serum protein antibody and anti-glomerular basement membrane before release.
Each ampoule of Atgam contains 250 mg of horse gamma globulin stabilised in 0.3 molar glycine to a pH of approximately 6.8.
No preservative or antimicrobial agent added. For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Solution for injection.
Atgam is a transparent to slightly opalescent aqueous protein solution, colourless to light brown, and nearly odourless. It may develop a slight granular or flaky deposit during storage. For information about inline filters, see Section 4.2 Dose and Method of Administration, Method of administration, Infusion instructions.

4 Clinical Particulars

4.1 Therapeutic Indications

Atgam is indicated for renal transplant patients in whom reduction of peripheral T-lymphocyte function, as measured by rosette-forming cell assay, could be desirable.
During controlled clinical trials, this immunosuppression has been demonstrated in renal allograft recipients treated with Atgam. When it was administered prophylactically with conventional immunosuppressive therapy, Atgam delayed the onset of the first rejection episode, and when it was administered at the time of the first rejection, Atgam resolved the acute rejection episode more frequently than did conventional therapy alone.

4.2 Dose and Method of Administration


Renal-allograft recipients.

Delaying the onset of allograft rejection.

The recommended dose is 15 mg/kg daily for 14 days, then on alternate days for 14 days for a total of 21 doses in 28 days. The first dose should be administered within 24 hours before or after the transplant.

Treatment of rejection.

The first Atgam dose can be delayed until the diagnosis of the first rejection episode. The recommended dose is 10 to 15 mg/kg daily for 14 days. Additional alternate-day therapy up to a total of 21 doses may be given.
Usually, Atgam is used concomitantly with azathioprine and corticosteroids, which are commonly used to suppress the immune response. Exercise caution during repeat courses of Atgam; carefully observe patients for signs of allergic reactions.
Adult renal allograft patients have received Atgam 10 to 30 mg/kg of bodyweight daily. The few children studied received 5 to 25 mg/kg daily. Atgam has been used to delay the onset of the first rejection episode and at the time of the first rejection episode. Most patients who received Atgam for the treatment of acute rejection had not received it starting at the time of transplantation.

Method of administration.

For intravenous infusion.

Skin testing.

To identify those at greatest risk of systemic anaphylaxis, skin testing potential recipients before commencing treatment is strongly recommended. A conservative, conventional approach would first employ epicutaneous (prick) testing with undiluted Atgam. If the subject does not show a wheal ten minutes after pricking, proceed to intradermal testing with 0.02 mL of a 1:1000 v/v (volume/volume) saline dilution of Atgam with a separate saline control injection of similar volume. Read the result at 10 minutes: a wheal at the Atgam site 3 mm or larger in diameter than that at the saline control site (or a positive prick test) suggests clinical sensitivity and an increased possibility of a systemic allergic reaction should the drug be used intravenously.
In the presence of a locally positive skin test to Atgam, serious consideration to alternative forms of therapy should be given. The risk to benefit ratio must be carefully weighed. If therapy with Atgam is deemed appropriate following a locally positive skin test, treatment should be administered in a setting where intensive life support facilities are immediately available and a physician familiar with the treatment of potentially life threatening allergic reactions is in attendance.
A systemic reaction such as generalised rash, tachycardia, dyspnoea, hypotension or anaphylaxis precludes an additional administration of Atgam.


The predictive value of this test has not been clinically proven. Allergic reactions to Atgam can occur in the presence of a negative skin test. Also, skin testing done as described above will not predict for later development of serum sickness.
See Section 4.4 Special Warnings and Precautions for Use; Section 4.8 Adverse Effects (Undesirable Effects).

Infusion instructions.

Parenteral drug products should be inspected visually for particulate matter and discolouration prior to administration whenever solution and container permit. Because Atgam is a gamma globulin product, it can be transparent to slightly opalescent, colourless to light brown, and may develop a slight granular or flaky deposit during storage.
Dilute Atgam in saline solution before intravenous infusion. Invert the IV bottle of saline so the undiluted Atgam does not contact the air inside.
Add the total daily dose of Atgam to one of the following sterile intravenous diluents to obtain a concentration not exceeding 4 mg of Atgam per mL:
0.90% sodium chloride solution;
5% glucose and 0.225% sodium chloride solution;
5% glucose and 0.45% sodium chloride solution.
Adding Atgam to glucose-only solutions is not recommended as low salt concentrations can cause precipitation. Highly acidic infusion solutions can also contribute to physical instability over time.
Atgam should not be kept in a diluted form for more than 24 hours (including actual infusion time). To reduce microbiological hazard use should be as soon as practicable after dilution. If storage is necessary, hold at 2°C to 8°C. Total time in dilution should not exceed 24 hours.
During clinical trials, most investigators chose to infuse Atgam into a vascular shunt, arteriovenous fistula, or a high-flow central vein through an in-line filter with a pore size of 0.2 to 1.0 micron. The inline filter should be used with all intravenous infusions to prevent the inadvertent administration of any insoluble material that may develop in the product during storage.
Using high-flow veins will minimise the occurrence of phlebitis and thrombosis.
Do not infuse a dose of Atgam in less than 4 hours.
Always keep a tray containing adrenaline, antihistamines, corticosteroids, syringes and an airway at the patient's bedside while Atgam is being administered.
Observe the patient continuously for possible allergic reactions throughout the infusion (see Section 4.8 Adverse Effects (Undesirable Effects)).
Diluted or undiluted Atgam should not be shaken. Excessive foaming and/or denaturation of the protein may occur. Diluted solutions should be gently rotated or swirled prior to use.

Dosage adjustment.

Elderly (≥ 65 years of age).

In general, the dose for an elderly patient should be selected with caution, usually starting at the low end of the dosage range (see Section 4.4 Special Warnings and Precautions for Use).

4.3 Contraindications

Do not administer Atgam to a patient who has had a severe systemic reaction (e.g. anaphylactic reaction) during prior administration of Atgam or any other equine gamma globulin preparation.

4.4 Special Warnings and Precautions for Use

Treatment with Atgam should be discontinued if any of the following occurs:
severe or unremitting thrombocytopenia;
severe or unremitting leucopenia.
See Section 4.8 Adverse Effects (Undesirable Effects), Management of adverse effects for further information on the treatment of these adverse effects.

Skin testing.

To identify those at greatest risk of systemic anaphylaxis, skin testing potential recipients before commencing treatment is strongly recommended (see Section 4.2 Dose and Method of Administration, Method of administration, Skin testing).

Transmission of infectious diseases.

In common with products derived from, or purified with equine and human blood components, the possibility of transmission of infectious diseases, including viral hepatitis, human immunodeficiency virus (HIV - the causative agent for AIDS or acquired immuno-deficiency syndrome), and theoretically, the Creutzfeldt-Jakob disease (CJD) agent must always be considered, and should be conveyed to patients who may receive the product.
All infections suspected to have been transmitted by this product should be reported by healthcare professionals. See Section 4.8 Adverse Effects (Undesirable Effects), Reporting suspected adverse effects.
The patients should be monitored for concurrent infection. Some studies have suggested an increase in the incidence of cytomegalovirus infection in patients receiving Atgam.

Specialised administration and medical facilities.

Only physicians experienced in immunosuppressive therapy should use Atgam.
Patients who receive Atgam should be managed in facilities equipped and staffed with adequate laboratory and supportive medical resources.

Immune-mediated reactions.

In rare instances, serious immune-mediated reactions have been reported with the use of Atgam. Clinical signs associated with anaphylaxis, other infusion associated reactions and serum sickness have been reported (see Section 4.8 Adverse Effects (Undesirable Effects)). Based on the mechanism of action of Atgam, there is a potential risk of cytokine release syndrome.
A systemic reaction such as a generalised rash, tachycardia, dyspnoea, hypotension or anaphylaxis precludes any additional administration of Atgam (see Section 4.2 Dose and Method of Administration, Method of administration, Skin testing).


Because Atgam is an immunosuppressive agent ordinarily given with corticosteroids and anti-metabolites, patients should be monitored carefully for signs of leucopenia, thrombocytopenia or concurrent infection.


In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded.


Monitor patients carefully for concurrent infection as in rare cases these can be fatal. Some studies have suggested an increase in the incidence of cytomegalovirus infection in patients receiving Atgam. If infection occurs, appropriate adjunctive therapy should be instituted promptly. The physician should decide whether or not to continue therapy with Atgam depending on clinical circumstances.

Antibodies to horse globulin.

Despite concurrent immunosuppressive agents, a number of Atgam treated patients have developed antibodies to horse globulin. There is inadequate experience to determine the efficacy and safety of repeated courses of Atgam for rejection crises, and its use in these circumstances should be undertaken only with great care.

Live-virus vaccines.

Live-virus vaccines may not replicate successfully and antibody response could be reduced when the vaccine is administered after immune globulin administration. Live-virus vaccines should ideally be administered six months after therapy with intravenous immune globulin.

Use in the elderly.

Clinical experience in a limited number of elderly patients (≥ 65 years of age) has not identified differences in responses between the elderly and younger patients. In general, the dose for an elderly patient should be selected with caution, usually starting at the low end of the dosage range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy in this age group.

Paediatric use.

Experience with children has been limited. Atgam has been administered safely to a small number of paediatric renal, liver and bone marrow allograft recipients and aplastic anaemia patients at dosage levels comparable to those in adults.

Effects on laboratory tests.

In patients with aplastic anaemia and other haematologic abnormalities who have received Atgam, abnormal tests of liver function and renal function have been observed.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Corticosteroids and other immunosuppressants.

When the dose of corticosteroids and other immunosuppressants is being reduced, some previously masked reactions to Atgam may appear. Under these circumstances, observe patients especially carefully during therapy with Atgam.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

No data available.
(Category C)
Atgam has not been evaluated in pregnant women. Atgam should be used during pregnancy only if the potential benefit outweighs the potential risk to the fetus.
Atgam has not been evaluated in lactating women. It is not known whether Atgam is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse effects in nursing neonates and infants from Atgam, a decision should be made whether to discontinue nursing or to discontinue the drug taking into account the importance of the drug to the mother.

4.7 Effects on Ability to Drive and Use Machines

No studies on the effect of ability to drive or use machines have been performed. Given the potential adverse reactions that may be experienced (e.g. dizziness, convulsion, confusional state, syncope), caution should be taken when driving or using machinery while on this medication (see Section 4.8 Adverse Effects (Undesirable Effects)).

4.8 Adverse Effects (Undesirable Effects)

The primary clinical experience with Atgam has been in renal allograft patients who were also receiving concurrent standard immunosuppressive therapy (azathioprine, corticosteroids).

Clinical trials.

In controlled trials, the following adverse effects were reported:

Frequency of > 5%.

Fever (45-60%), chills (15-30%), leucopenia (30-50%), thrombocytopenia (44-52%), dermatological reactions such as rash, pruritus, urticaria, wheal and flare (15-25%).

Frequency of > 1% to < 5%.

Arthralgia, chest or back pain or both, clotted A/V fistula, diarrhoea, dyspnoea, headache, hypotension, nausea or vomiting or both, night sweats, pain at the infusion site, peripheral thrombophlebitis, stomatitis.

Frequency of < 1%.

Anaphylaxis, dizziness, agitation, weakness or faintness, oedema, herpes simplex reactivation, hiccoughs or epigastric pain, hyperglycaemia, hypertension, iliac vein obstruction, laryngospasm, localised infection, lymphadenopathy, malaise, myalgia, paraesthesia, possible serum sickness, possible encephalitis, pleural effusions, pulmonary oedema, periorbital oedema, renal artery thrombosis, proteinuria, seizures, systemic infection, tachycardia, toxic epidermal necrosis, wound dehiscence.
Medical events similar to those listed above have been reported in patients receiving Atgam for reasons other than prevention of renal allograft rejection.

Post-marketing experience.

In post-marketing experience, the frequency of adverse effects in voluntary reported cases is as follows:

Frequency of > 10%.

Fever (51%), chills (16%), thrombocytopenia (30%), leucopenia (14%), rashes (27%), systemic infection (13%).

Frequency of > 5 to < 10%.

Abnormal renal function tests, serum sickness-like symptoms, dyspnoea/ apnoea, arthralgias, chest, back and flank pain, diarrhoea and nausea and/or vomiting.

Frequency of < 5%.

Hypertension, herpes simplex infection, pain, swelling or redness at infusion site, eosinophilia, headache, myalgias or leg pains, hypotension, anaphylaxis, tachycardia, bradycardia, oedema, localised infection, malaise, seizures, GI bleeding or perforation, deep vein thrombosis, sore mouth/ throat, hyperglycaemia, acute renal failure, abnormal liver function tests, confusion or disorientation, cough, neutropenia or granulocytopenia, anaemia, thrombophlebitis, dizziness, epigastric or stomach pain, lymphadenopathy, pulmonary oedema or congestive heart failure, abdominal pain, nosebleed, vasculitis, aplasia or pancytopenia, abnormal involuntary movement or tremor, rigidity, sweating, laryngospasm/ oedema, haemolysis or haemolytic anaemia, viral hepatitis, faintness, enlarged or ruptured kidney, paraesthesia, renal artery thrombosis, syncope.

Management of adverse effects.

The recommended management for some of the adverse effects that could occur during treatment with Atgam follows.


Anaphylaxis is uncommon but serious, and may occur during therapy with Atgam. If this condition does occur, infusion of Atgam should be discontinued immediately; 0.3 mL aqueous adrenaline (1:1,000 dilution) should be administered intramuscularly along with steroids; respiration should be assisted and other resuscitative measures provided. Do not resume therapy with Atgam.


Haemolysis can usually be detected only in the laboratory. Fulminant haemolysis has been reported rarely. Appropriate treatment of haemolysis often includes transfusion of erythrocytes; if necessary, administer intravenous mannitol, frusemide, sodium bicarbonate, and fluids. Severe and unremitting haemolysis may necessitate discontinuation of therapy with Atgam.

Thrombocytopenia and leucopenia.

Thrombocytopenia and leucopenia are usually transient. Platelet and white cell counts generally return to adequate levels without interrupting therapy and with transfusions. If thrombocytopenia and leucopenia become severe, it may be helpful to decrease the dose of concomitant immunosuppressant (particularly azathioprine). If after one or two days the situation does not improve, the dose of Atgam may also be reduced (see Section 4.4 Special Warnings and Precautions for Use).

Respiratory distress.

Respiratory distress may indicate an anaphylactoid reaction. Infusion of Atgam should be discontinued. If distress persists, antihistamine, adrenaline, methylprednisolone, or some combination of the three should be administered.

Pain in chest, flank or back.

Pain in the chest, flank or back may indicate anaphylaxis or haemolysis. Treatment is the same as for respiratory distress or, if haemolysis has occurred, see Haemolysis as listed in this section above.


Hypotension may indicate anaphylaxis. Infusion of Atgam should be discontinued and blood pressure stabilised with pressors if necessary.

Chills and fever.

Chills and fever occur in most patients receiving Atgam. Atgam may release endogenous leucocyte pyrogens. Prophylactic and/or therapeutic administration of antihistamines or corticosteroids generally controls this reaction.

Chemical phlebitis.

Chemical phlebitis can be caused by infusion of Atgam through peripheral veins. This often can be avoided by administering the infusion solution into a high-flow vein. A subcutaneous arterialised vein produced by a Brescia fistula is also a useful administration site.

Itching and erythema.

Itching and erythema probably result from the effect of Atgam on blood elements. Antihistamines generally control the symptoms.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at

4.9 Overdose

Because of its mode of action and because it is a biological substance, the maximum tolerated dose of Atgam would be expected to vary from patient to patient. To date, the largest single daily dose administered to a patient (renal transplant recipient) was 7,000 mg administered at a concentration of approximately 10 mg/mL of saline, seven times the recommended total dose and infusion concentration. In this patient, administration of Atgam was not associated with any signs of acute intoxication or late sequelae.
The greatest number of doses (10 to 20 mg/kg/dose) that can be administered to a single patient has not yet been determined. Some renal transplant patients have received up to 50 doses in 4 months, and others have received 28-day courses of 21 doses followed by as many as 3 more courses for the treatment of acute rejection. The incidence of toxicological manifestations did not increase with any of these regimens, however close monitoring of the patient is recommended.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).


Atgam is available only to hospital units which are equipped and staffed for transplant surgery.

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

Atgam is a lymphocyte-selective immunosuppressant as demonstrated by its reduction in the peripheral circulation of thymus-dependent T-lymphocytes that form rosettes with sheep erythrocytes. This anti-lymphocyte effect is believed to reflect an alteration of the function of the T-lymphocytes, which are responsible in part for cell-mediated immunity and are involved in humoral immunity. In addition to its anti-lymphocyte activity, Atgam contains low concentrations of antibodies against other formed elements of blood. In rhesus and cynomolgus monkeys, Atgam reduces lymphocytes in the thymus-dependent areas of the spleen and lymph nodes. It also decreases the circulating sheep-erythrocyte rosetting lymphocytes that can be detected, but Atgam does not cause severe lymphopenia.
In general, when Atgam is given with other immunosuppressive therapy, such as anti-metabolites and corticosteroids, the patient's own antibody response to horse gamma globulin is minimal.

Clinical trials.

No data available.

5.2 Pharmacokinetic Properties

In a small clinical study, Atgam administered with other immunosuppressive therapy and measured as horse IgG had a serum half-life of 5.7 ± 3 days.

5.3 Preclinical Safety Data

In the routine development of Atgam, aliquots of the various clinical lots have been infused intravenously to either Macaca rhesus or Macaca irus monkeys. Two dosage regimens have been used: 100 mg/kg on day 0, 200 mg/kg on day 2 and 400 mg/kg on day 4 or, currently, 50 mg/kg on days 0, 2, 4 and 7. A three week observation period has followed the last infusion in either dosage regimen. These studies do not fully explore the toxicological potential of Atgam.
The observed changes could have been anticipated on the basis of the anti-lymphocyte activity with Atgam. Within 24 hours after infusion, decreased peripheral blood lymphocytes and increased total leukocyte and neutrophil counts occurred. Decreased thymus size with involution or atrophy or both and decreased lymphocyte populations in the thymus-dependent areas of the spleen and lymph nodes were noted. The atrophy was most prevalent in animals that received the higher doses.
In animals receiving either dosage regimen, packed cell volume, total erythrocyte counts, and haemoglobin concentrations have decreased, and reticulocytes and nucleated erythrocytes have increased enough to be classified as anaemia. An occasional death believed to have resulted from anaemia has occurred.
Transient decreases in blood platelet counts have also occurred. Thrombus formation occurred frequently along the routes of infusion, i.e. the saphenous and femoral veins. However, the incidence of thrombi has decreased since inline filters have been used during infusion. In these animals no evidence of DIC (disseminated intravascular coagulation) has appeared.


No data available.


No data available.

6 Pharmaceutical Particulars

6.1 List of Excipients

Glycine, hydrochloric acid, sodium hydroxide, water for injections.

6.2 Incompatibilities

Adding Atgam to glucose-only solutions is not recommended as low salt concentrations can cause precipitation. Highly acidic infusion solutions can also contribute to physical instability over time.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Before dilution.

Store at 2°C to 8°C. Refrigerate. Do not freeze. To protect from light, keep the ampoule in the carton until use.

After dilution.

To reduce microbiological hazard use should be as soon as practicable after dilution. If storage is necessary, hold at 2°C to 8°C for a maximum of 24 hours including infusion time.

6.5 Nature and Contents of Container

Atgam is available in 5 mL ampoules containing 250 mg/5 mL equine antithymocyte immunoglobulin.
Atgam is available in packs of 5 ampoules.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of in accordance with local requirements.

6.7 Physicochemical Properties

Chemical structure.

No data available.

CAS number.

No data available.

7 Medicine Schedule (Poisons Standard)

Prescription Only Medicine (Schedule 4).

Summary Table of Changes