Imfinzi

Durvalumab is a programmed death-ligand 1 (PD-L1) blocking antibody indicated for the treatment of various cancers, including non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), and biliary tract cancer, by enhancing the body's immune response against tumor cells.

The dosage of Durvalumab is determined by the specific type of cancer being treated and, in some cases, the patient's body weight. Healthcare providers typically use one of two dosing strategies: weight-based dosing or fixed (flat) dosing.

• For Stage III NSCLC: The standard dose is either 10 mg/kg (milligrams per kilogram of body weight) administered every 2 weeks, or a fixed dose of 1500 mg administered every 4 weeks. This treatment usually continues for up to 12 months unless the disease progresses or side effects become too severe.
• For Extensive-Stage SCLC: When used with chemotherapy, the dose is typically 1500 mg every 3 weeks for 4 cycles, followed by 1500 mg as a single agent every 4 weeks.
• For Biliary Tract Cancer: The dose is 1500 mg every 3 weeks when given with chemotherapy, followed by 1500 mg every 4 weeks as a single agent.
• For Hepatocellular Carcinoma: When used with tremelimumab, a single dose of tremelimumab 300 mg is given with Durvalumab 1500 mg, followed by Durvalumab 1500 mg every 4 weeks.

The safety and effectiveness of Durvalumab in pediatric patients (children and adolescents under the age of 18) have not been established. Clinical trials are ongoing to determine if there is a role for this medication in childhood cancers, but currently, it is NOT approved for pediatric use. Healthcare providers will not typically prescribe this medication to children outside of a controlled clinical trial setting.

Renal Impairment

Based on population pharmacokinetic analyses, no dose adjustment is recommended for patients with mild or moderate renal (kidney) impairment. There is limited data for patients with severe renal impairment (Creatinine Clearance less than 30 mL/min), so healthcare providers will monitor these patients closely for adverse reactions.

Hepatic Impairment

No dose adjustment is recommended for patients with mild hepatic (liver) impairment. Durvalumab has not been studied in patients with moderate or severe hepatic impairment; therefore, it should be used with extreme caution in these populations, as the liver is involved in the eventual clearance of protein degradation products.

Elderly Patients

In clinical studies, no overall differences in safety or effectiveness were observed between patients aged 65 and older and younger patients. Consequently, no specific dose adjustments are required based solely on age, though older adults may be more susceptible to certain immune-mediated side effects.

Durvalumab is administered as an intravenous (IV) infusion by a healthcare professional in a clinical setting (such as a hospital or infusion center).

1. 1Preparation: The medication is diluted into an IV bag. It should not be co-administered with other drugs through the same IV line.
2. 2Infusion Duration: The infusion is typically delivered over 60 minutes. During this time, a nurse will monitor your vital signs (blood pressure, heart rate, temperature) for signs of an infusion reaction.
3. 3Frequency: You will receive an infusion every 2, 3, or 4 weeks, depending on your specific treatment plan.
4. 4Storage: The vials are stored in a refrigerator at 2°C to 8°C (36°F to 46°F) and must be protected from light. Once diluted, the solution should be used immediately or stored refrigerated for no more than 24 hours.

If you miss an appointment for a Durvalumab infusion, contact your healthcare provider immediately to reschedule. It is critical to maintain the treatment schedule to ensure the medication remains at an effective level in your bloodstream. Your doctor will determine the best timing for your next dose based on when the missed dose was supposed to occur.

Because Durvalumab is administered by trained medical professionals, an overdose is highly unlikely. There is no specific antidote for a Durvalumab overdose. In the event of an accidental administration of an excessive dose, healthcare providers will provide supportive care and monitor the patient closely for exaggerated side effects, particularly immune-mediated reactions.

> Important: Follow your healthcare provider's dosing instructions precisely. Do not attempt to alter your infusion schedule without direct medical guidance, as this could impact the effectiveness of your cancer treatment.

Many patients receiving Durvalumab will experience some side effects. While many are manageable, they require close communication with your oncology team. Common side effects include:

• Cough and Shortness of Breath: This is very common, especially in lung cancer patients. It may feel like a persistent dry cough or a feeling of being 'winded' during light activity.
• Fatigue: A profound sense of tiredness or exhaustion that does not always improve with rest. This is the most frequently reported side effect.
• Musculoskeletal Pain: Aches and pains in the muscles, bones, or joints. This can range from mild stiffness to significant discomfort.
• Rash and Itching (Pruritus): Skin reactions are common. You may notice red, bumpy, or itchy patches on the skin.

Durvalumab is a potent immunotherapy that requires careful medical supervision. The most critical safety concern is the potential for the immune system to attack healthy tissues (immune-mediated adverse reactions). These reactions can occur in any organ or tissue and can happen at any time during treatment or even after treatment has stopped. Patients must be educated to recognize the early signs of inflammation and report them to their oncology team immediately.

No FDA black box warnings for Durvalumab. While it lacks a black box warning, the 'Warnings and Precautions' section of the prescribing information is extensive and details life-threatening risks associated with immune-mediated organ damage.

• Immune-Mediated Pneumonitis: This is a significant risk, especially in patients who have previously received radiation to the chest. It can lead to permanent lung scarring or respiratory failure.

There are no specific drugs that are strictly contraindicated (forbidden) for use with Durvalumab based on direct chemical interactions. However, the use of live vaccines is generally avoided during treatment. Because Durvalumab affects the immune system, live vaccines (such as the MMR or yellow fever vaccine) could potentially cause a serious infection or fail to provide immunity. Always consult your oncologist before receiving any vaccination.

• Systemic Corticosteroids (e.g., Prednisone): Using high doses of steroids or other immunosuppressants before starting Durvalumab should be avoided if possible. These drugs can interfere with Durvalumab’s ability to 'wake up' the immune system to fight cancer, potentially reducing its effectiveness. However, once a patient is on Durvalumab, corticosteroids are the primary treatment for managing immune-mediated side effects.
• Immunosuppressive Drugs (e.g., Cyclosporine, Methotrexate): Like steroids, these medications can blunt the intended therapeutic effect of Durvalumab. They are typically only used if necessary to treat a severe adverse reaction caused by the immunotherapy itself.

There are very few absolute contraindications for Durvalumab, as it is often a life-extending treatment for serious cancers. However, it must NEVER be used in the following case:

• Severe Hypersensitivity: Patients who have had a severe, life-threatening allergic reaction (anaphylaxis) to Durvalumab or any of the ingredients in the formulation (such as L-histidine or polysorbate 80) should not receive the drug. The mechanism is an immediate IgE-mediated immune response that can cause airway closure and circulatory collapse.

Relative contraindications are conditions where the risk of treatment might outweigh the benefit, or where extreme caution is required. Your doctor will perform a careful risk-benefit analysis if you have:

• Active Autoimmune Disease: Conditions such as systemic lupus erythematosus (SLE), Crohn’s disease, ulcerative colitis, or multiple sclerosis. Because Durvalumab 'turns on' the immune system, it can cause a severe and potentially fatal flare-up of these pre-existing conditions.

Durvalumab is classified as having Embryo-Fetal Toxicity. Based on its mechanism of action and animal studies, Durvalumab can cause fetal harm when administered to a pregnant woman. It is known that maternal IgG antibodies cross the placenta; therefore, Durvalumab has the potential to be transmitted from the mother to the developing fetus. This can lead to an increased risk of immune-mediated disorders or even fetal death.

• Contraception: Females of reproductive potential should use effective contraception during treatment with Durvalumab and for at least 3 months after the last dose.
• Pregnancy Testing: Healthcare providers will typically verify pregnancy status in females of reproductive potential prior to initiating treatment.

It is not known whether Durvalumab is excreted in human milk. While many maternal antibodies (IgG) are present in breast milk, they are often broken down in the infant's digestive tract. However, because of the potential for serious adverse reactions in a breastfed child, women are advised not to breastfeed during treatment and for at least 3 months after the final dose. The risk-benefit consideration usually favors the mother's cancer treatment over breastfeeding.

Durvalumab is a highly specialized monoclonal antibody (IgG1κ) that targets the Programmed Death-Ligand 1 (PD-L1) protein. In a healthy body, the PD-1/PD-L1 pathway serves as a checkpoint to prevent the immune system from attacking the body's own cells. Cancer cells often overexpress PD-L1, which binds to the PD-1 receptor on T-cells, effectively 'turning off' the T-cell's ability to kill the cancer cell.

Durvalumab binds with high affinity (very strongly) to PD-L1. By doing so, it physically blocks PD-L1 from interacting with both PD-1 and CD80. Blocking these interactions restores the T-cell's ability to recognize and destroy the tumor cell. Because Durvalumab is an IgG1 antibody, it has been engineered to reduce 'antibody-dependent cell-mediated cytotoxicity' (ADCC), meaning it focuses on blocking the receptor rather than destroying the cells it binds to directly.

The pharmacodynamics of Durvalumab involve its ability to maintain receptor occupancy (staying attached to the target). Studies show that at the recommended doses, Durvalumab achieves >95% occupancy of the PD-L1 receptors on circulating T-cells. This high level of occupancy is maintained throughout the dosing interval (2 to 4 weeks), ensuring continuous immune activation against the tumor. There is no evidence of 'tolerance' (the drug becoming less effective over time) in the way that some small-molecule drugs experience.