Keytruda 100mg Injection is used in the treatment of several cancers, either alone or in combination with other cancer treatments. Depending on the indication, its approved uses include:

• Advanced or resected melanoma

• Non-small cell lung cancer

• Classical Hodgkin lymphoma

• Urothelial carcinoma

• Head and neck squamous cell carcinoma

• Renal cell carcinoma

• Colorectal cancer with MSI-H or dMMR status

• Gastric and gastro-oesophageal junction cancer

• Oesophageal cancer

• Triple-negative breast cancer

• Endometrial cancer

• Cervical cancer

• Biliary tract cancer

• Malignant pleural mesothelioma

• Selected ovarian, fallopian tube and primary peritoneal cancers

Some indications require specific tumour markers such as PD-L1 expression or MSI-H/dMMR status, while others are used in combination with chemotherapy, radiotherapy or targeted cancer medicines. The exact indication and treatment combination are determined by the treating oncologist.

Pembrolizumab is a PD-1 inhibitor. PD-1 is a protein present on immune cells that can act as a checkpoint, limiting immune activity when it binds to its partner proteins on other cells.

Some cancer cells use this pathway to reduce the immune system's ability to recognise them. Pembrolizumab binds to PD-1 and blocks its interaction with PD-L1 and PD-L2. This can restore T-cell activity against cancer cells and help the immune system recognise and attack the tumour.

No formal pharmacokinetic interaction studies have been conducted with pembrolizumab. As it is cleared from the circulation through catabolism, metabolic drug interactions are not expected.

Tell your doctor about all medicines and supplements you are taking. Systemic corticosteroids or other immunosuppressive medicines used before starting treatment may interfere with the immune response produced by pembrolizumab. However, corticosteroids or other immunosuppressive medicines may be prescribed during treatment to manage immune-mediated side effects.

• Store Keytruda 100mg Injection in a refrigerator at 2°C to 8°C.

• Do not freeze.

• Keep the vial in the original package to protect it from light.

• Do not shake the vial.

• The medicine should be prepared and administered by trained healthcare professionals according to the prescribed instructions.

Keytruda 100mg Injection is given only by a healthcare professional as an intravenous infusion. The 100mg/4ml vial is a concentrate that must be appropriately diluted before administration.

The recommended adult dose is generally either 200mg every 3 weeks or 400mg every 6 weeks, depending on the indication. The infusion is administered over 30 minutes. Some paediatric patients with specific indications may receive weight-based dosing.

The treatment duration depends on the cancer being treated, response to treatment and tolerability. Keytruda should not be given as an intravenous push or bolus injection.

Keytruda can cause side effects because it activates the immune system. Some immune-mediated reactions can affect healthy organs and may occur during treatment or even after the last dose.

Common side effects

• Fatigue

• Diarrhoea

• Nausea

• Decreased appetite

• Skin rash or itching

• Joint or muscle pain

• Headache

• Cough or shortness of breath

• Constipation

• Fever or chills

The frequency and severity of side effects can vary depending on whether Keytruda is given alone or with chemotherapy or other treatments.

Serious side effects

Seek immediate medical attention if you develop symptoms suggesting:

• Pneumonitis

• Colitis

• Hepatitis

• Nephritis

• Thyroid disorders or other endocrine problems

• Type 1 diabetes or diabetic ketoacidosis

• Severe skin reactions

• Myocarditis

• Neurological immune-mediated reactions

• Severe infusion-related reactions

These reactions can sometimes be serious or life-threatening and may require interruption or permanent discontinuation of treatment.

• Keytruda treatment should be started and supervised by an oncologist experienced in cancer treatment.

• Attend all scheduled appointments so your response to treatment and possible immune-mediated side effects can be monitored.

• Tell your doctor about any new or worsening symptoms, even if they appear unrelated to the cancer.

• Report persistent diarrhoea, abdominal pain, breathing difficulty, cough, changes in vision, severe rash, unusual fatigue, changes in urination or yellowing of the skin or eyes promptly.

• Blood tests may be required to monitor liver, kidney and thyroid function during treatment.

• If you have an autoimmune condition, a previous organ transplant or a history of stem-cell transplantation, tell your doctor before treatment.

• Do not stop or delay treatment on your own. Your oncologist will determine whether treatment should continue, be withheld or discontinued based on your response and side effects.

• Carry the Keytruda patient information card provided with your treatment so healthcare professionals are aware that you are receiving pembrolizumab.