The length of immunotherapy depends on what you’re asking about—an individual treatment session or the full course of care. A single immunotherapy infusion usually takes 30 minutes to a few hours, depending on the medication. However, a full course of immunotherapy typically lasts 1 to 2 years, though some patients may stop earlier or continue longer depending on how well the treatment works and how well it’s tolerated.

How Long Is a Single Immunotherapy Session?

The length of each session can vary based on the type of immunotherapy, the dose, and your treatment center’s protocols. In general:

Your first session may take longer because of additional preparation, monitoring, and observation for side effects.

Learn more about immunotherapy treatments: Immunotherapy for Cancer — National Cancer Institute

How Long Does a Full Course of Immunotherapy Take?

The total duration of immunotherapy depends on your cancer type, treatment plan, and how your body responds. Common scenarios include:

• Fixed-duration treatment: Some immunotherapy regimens are given for a set period, often 1 to 2 years. Treatment may be stopped early if there is a strong response or significant side effects.
• Ongoing treatment:  For certain cancers, such as lung, kidney, or liver cancer, treatment may continue as long as it’s working and side effects remain manageable.
• Combination treatment plans: When immunotherapy is combined with chemotherapy, radiation, or surgery, the overall timeline depends on the full treatment plan rather than immunotherapy alone.

It’s also important to know that immunotherapy can take time to work. Because it helps your immune system fight cancer, visible results may take 2 months or longer to appear.

Learn more about treatment schedules: How Often Do You Receive Immunotherapy? — Moffitt Cancer Center

What Factors Affect How Long Immunotherapy Takes?

Several factors influence how long immunotherapy may continue:

• Cancer type and stage: More advanced or metastatic cancers often require longer treatment.
• Tumor response:  Treatment may continue, stop, or change depending on whether the cancer shows a complete response, partial response, or remains stable.
• Side effects: Immune-related side effects (called irAEs) may lead to treatment delays, dose adjustments, or discontinuation.
• Biomarkers: Factors such as PD-L1 expression, tumor mutational burden (TMB), or MSI status can influence the duration of treatment.
• Treatment setting: Whether immunotherapy is used before surgery (neoadjuvant), after surgery (adjuvant), or for advanced disease affects the expected duration.