What is the significance of Interleukin-2 (IL-2) level of 39?

From the Guidelines

Interleukin-2 (IL-2) at a level of 39 is not a standard unit of measurement for IL-2, but rather 600,000 IU/kg (which is equivalent to 39 million units for an average adult) is a typical dose used for immunotherapy in certain cancers. The significance of this dose is that it is used to stimulate T-cell proliferation and activate natural killer cells, enhancing the immune system's ability to recognize and destroy cancer cells, particularly in metastatic renal cell carcinoma and metastatic melanoma 1.

Key Considerations

• The recommended regimen is administered intravenously every 8 hours for up to 14 doses, followed by a rest period of 9 days, then another course of treatment.
• This high-dose IL-2 therapy should be administered in a hospital setting under close supervision due to potential severe side effects including capillary leak syndrome, hypotension, and multi-organ dysfunction.
• Treatment should be temporarily withheld if severe toxicities develop and permanently discontinued if life-threatening complications occur.
• Patients should be adequately hydrated before treatment and may require vasopressors for blood pressure support during therapy.
• This treatment is contraindicated in patients with significant cardiac, pulmonary, renal, or hepatic dysfunction.

Management of Toxicities

• Hypotension is less common with the abbreviated course of high-dose IL-2 used for TIL than with therapeutic IL-2; about 8%–10% developed grade 3 or higher hypotension in clinical studies 1.
• Blood pressure target is based on baseline blood pressure and is assessed prior to each dose.
• For patients with blood pressure not meeting target, administer small (250–500 mL) normal saline (NS) or lactated Ringer’s (LR) bolus over 30–60 min.
• Repeat blood pressure 30 min after intravenous bolus, and if not meeting target, repeat another 250 mL intravenous bolus.
• If hypotension persists despite intravenous fluid boluses, IL-2 may be discontinued.

Monitoring and Supportive Care

• Patients should be closely monitored for signs of toxicity, including capillary leak syndrome, hypotension, and multi-organ dysfunction.
• Supportive therapy prior to IL-2 administration includes acetaminophen, indomethacin, pantoprazole, and meperidine as needed.
• Maintenance fluids are typically not needed for IL-2 and fluids should be administered cautiously during active IL-2 treatment.
• Urine output should be assessed prior to each dose; the goal should be to maintain a urine output of at least 0.5 mL/kg/hour. In summary, IL-2 at a dose of 600,000 IU/kg (equivalent to 39 million units for an average adult) is a crucial component of immunotherapy for certain cancers, but requires close monitoring and supportive care to manage potential toxicities 1.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Interleukin-2 (IL-2) Level Significance

The significance of an Interleukin-2 (IL-2) level of 39 is not directly addressed in the provided studies. However, the studies discuss the role of IL-2 in cancer treatment, its toxicities, and strategies for safe administration.

IL-2 in Cancer Treatment

• High-dose IL-2 is used to treat metastatic melanoma and renal cell carcinoma, resulting in objective responses in 15-20% of patients 2.
• IL-2 therapy can produce durable responses in melanoma and renal cancer patients, but it is only effective in a fraction of patients and can cause serious side effects 3.
• The use of high-dose IL-2 therapy can increase the rate of toxicities and interfere with the activity of endothelial cells and effector T cells in the tumor microenvironment 4.

IL-2 Toxicities and Administration

• High-dose IL-2 is associated with significant morbidity, and its toxicity can manifest in multiple organ systems, including the heart, lungs, kidneys, and central nervous system 5.
• Safe and effective administration of high-dose IL-2 requires an experienced healthcare team, strict patient-eligibility criteria, standardized administration and patient assessment guidelines, and adherence to administration criteria and retreatment contraindications 5, 6.

Prognostic Significance of IL-2 Treatment

• Stable disease following high-dose IL-2 treatment is associated with a survival advantage, and the disease control rate (CR + PR + SD) may be a more meaningful endpoint for future clinical studies of tumor immunotherapy 2.