Key takeaways
- A person receives subcutaneous immunotherapy as an injection under the skin. This treatment method has shown similar effectiveness to intravenous (IV) infusions that healthcare professionals often use to treat cancer.
- Subcutaneous immunotherapy injections require much less time than IV infusions. While a person might need to spend hours at each infusion appointment, a subcutaneous injection takes only a few minutes.
- People whose veins are difficult to access or who cannot tolerate long infusion sessions might be good candidates for subcutaneous treatment. People can talk with their doctors about their options.
“Immunotherapy” is a broad term for treatments that modify the immune system to help it find and eliminate cancer cells.
Immunotherapies work in many different ways. Some block signals that hide cancer from the immune system, while others bind to cancer cells, making them easier for the immune system to spot. In some people, immunotherapies can enhance immune cells, enabling them to better recognize cancer cells.
Traditionally, people have received immunotherapy treatments by intravenous (IV) infusion, directly into a vein, similarly to many types of chemotherapy. Healthcare professionals must perform the infusions, so a person who is receiving immunotherapy may need to spend several hours in a clinical setting every few weeks.
While IV immunotherapy continues to play a major role in cancer treatment, emerging subcutaneous forms of immunotherapy drugs may provide similar outcomes in a fraction of the time.
This article examines common questions about subcutaneous immunotherapy injections for cancer treatment.
Cancer types can vary greatly from each other, and each type or subtype may have unique biological features that help it grow and evade the immune system. Because immunotherapy targets specific immune signals or cancer features, it works only on cancers that have those markers.
Immunotherapy is not yet available to treat every type of cancer, but it has shown possible benefits for treating the following types:
- brain cancer
- lung cancer
- breast cancer
- cervical cancer
- bladder cancer
- colorectal cancer
- melanoma
- liver cancer
- lymphoma
- skin cancer
- prostate cancer
- ovarian cancer
The subcutaneous form of an immunotherapy drug works on the immune system in the same way as the IV form, but it enters the body in a different way, and the body absorbs it differently. A subcutaneous injection is given into the fatty layer just under the skin, while an IV infusion goes into a vein.
With subcutaneous injection, a person’s body absorbs the drug
Because an IV infusion of immunotherapy goes directly into the bloodstream, the medication travels throughout the body rapidly and can reach peak drug levels more quickly than a subcutaneous drug can.
The dosing for these two forms of medication may differ, and as a result, they may have different costs for the medical facility and for the person receiving treatment. Staff at the facility can help a person find out whether choosing subcutaneous treatment over IV treatment will affect their out-of-pocket costs.
Subcutaneous immunotherapy may have several advantages over IV infusions.
According to a 2025 scientific commentary, many subcutaneous immunotherapies are as effective at treating cancer as IV infusions and can be administered in a fraction of the time. As a result, this type of treatment allows people to avoid long infusion appointments and reduces clinical costs by cutting down on staff time and required supplies.
In September 2024, the Food and Drug Administration (FDA) approved the subcutaneous drug Tecentriq Hybreza, which reduced the typical administration time by 80%. According to the FDA, a standard subcutaneous dose takes only
More recently, in 2025, the FDA approved a subcutaneous form of the drug Keytruda. An IV infusion of Keytruda takes about 30 minutes, while a subcutaneous injection takes about 1 minute.
Shorter administration times and a less invasive administration process are preferred by many people, who report feeling less burdened overall by the treatment process.
A person might be a good candidate for subcutaneous immunotherapy if:
- their immune system is working properly
- they have a type of cancer that has the necessary immune targets
- their veins are difficult to access
- they are not responding to other treatments
- they cannot tolerate long IV infusions
As with IV immunotherapy, a person will receive subcutaneous immunotherapy treatments
In most cases, the subcutaneous form of an immunotherapy drug will have the same side effects as the IV form of that drug.
Subcutaneous injections may be more likely to cause injection-site reactions.
Cancer cells can change, and those changes may cause immunotherapy to become less effective.
If subcutaneous immunotherapy is no longer effective, doctors
For some people, combining immunotherapy with another type of treatment, such as chemotherapy, may be more effective.
If treatment options are limited, a person’s treatment team may suggest that they take part in a clinical trial. A trial may provide the opportunity for a person to receive an emerging therapy.
Healthcare professionals have traditionally given immunotherapy treatment for cancer in the form of IV infusions. Many infusions require the use of a catheter or an IV line at each visit, and each appointment may be hours long.
Subcutaneous immunotherapy is given as an injection just under the skin. This form of treatment allows doctors to reduce treatment times and makes treatment faster and easier for many people living with cancer.
Research has shown that approved subcutaneous immunotherapies are as safe and effective as IV immunotherapy, but not all immunotherapy drugs for cancer are available in subcutaneous form.