Nivolumab is immunotherapy, not chemotherapy. Sold under the brand name Opdivo, it belongs to a class of drugs called immune checkpoint inhibitors. Rather than attacking cancer cells directly the way chemotherapy does, nivolumab works by helping your immune system recognize and destroy them. The distinction matters because the two treatments work through completely different biological pathways and produce very different side effects.
How Nivolumab Works
Cancer cells are skilled at hiding from your immune system. They do this by displaying a protein on their surface called PD-L1, which acts like a “don’t attack me” signal. This signal connects with a receptor called PD-1 on your immune cells, essentially putting those cells to sleep when they should be fighting.
Nivolumab is a lab-made antibody that blocks the PD-1 receptor on immune cells. With that receptor blocked, cancer cells can no longer flip the off switch, and your immune system reactivates against the tumor. This is why nivolumab is classified as a PD-1 inhibitor. In lab studies, nivolumab alone showed no direct ability to kill cancer cells. Its entire effect comes from unleashing the immune response that was already there but being suppressed.
Why It’s Not Chemotherapy
Chemotherapy kills cancer cells directly, primarily by triggering a self-destruct process in cells that divide rapidly. It’s effective but indiscriminate: it damages healthy fast-dividing cells too, which is why it causes hair loss, nausea, and low blood counts. The drug itself is the weapon.
Nivolumab takes the opposite approach. The drug doesn’t touch the cancer. Instead, it removes the brakes on your immune system and lets your own T cells do the killing. This fundamental difference shapes everything about the treatment, from the side effects you experience to how long the benefits can last. Because immunotherapy can create immune “memory,” some patients maintain responses long after treatment ends, something chemotherapy rarely achieves.
Side Effects Compared to Chemotherapy
Because nivolumab revs up the immune system rather than poisoning fast-growing cells, its side effect profile looks nothing like traditional chemo. You’re unlikely to lose your hair or experience the severe nausea that chemotherapy is known for. Instead, the main risks involve your immune system becoming overactive and attacking healthy tissues.
The most common serious side effects involve the lungs, the digestive tract, and the liver. Pneumonitis (lung inflammation) is the leading cause of serious complications. Gastrointestinal problems account for about 7.7% of serious events, and liver inflammation about 6.6%. These are called immune-related adverse events, and they happen because the same immune cells now fighting cancer can sometimes mistake normal organs for threats. The good news: large analyses comparing nivolumab to conventional treatment found that it did not increase the overall risk of serious or fatal side effects.
When Nivolumab Is Combined With Chemotherapy
Even though nivolumab isn’t chemotherapy, the two are frequently used together. This can cause confusion, but the combination is intentional. Chemotherapy can make tumors more visible to the immune system by exposing new proteins on dying cancer cells, drawing immune cells into the tumor, and making cancer cells more vulnerable to immune attack. In lab studies, combining nivolumab with a common chemo drug called cisplatin boosted cancer cell death to 89%, compared to 49% with cisplatin alone.
In lung cancer specifically, nivolumab is FDA-approved for use alongside platinum-based chemotherapy both before surgery and as a first-line treatment for advanced disease. In a trial of esophageal squamous cell carcinoma, patients who received nivolumab plus chemotherapy survived a median of 15.4 months compared to 9.1 months with chemotherapy alone among those whose tumors expressed PD-L1. That’s roughly an extra six months of survival. Even across all patients regardless of PD-L1 status, the combination extended median survival from 10.7 to 13.2 months.
If your oncologist recommends nivolumab with chemotherapy, you’ll be receiving both types of treatment simultaneously. You may experience side effects from both, though your care team will monitor for immune-related reactions specifically.
What Treatment Looks Like
Nivolumab is given as an intravenous infusion that takes about 30 minutes. How often you go in depends on your specific treatment plan. When used alone, it’s typically given every two weeks (at 240 mg) or every four weeks (at 480 mg). When combined with chemotherapy or another immunotherapy drug called ipilimumab, infusions are usually every three weeks at 360 mg. These sessions are shorter than many chemotherapy infusions, which can take several hours.
Treatment continues until the cancer progresses or side effects become unmanageable. For some indications, like after surgical removal of melanoma or bladder cancer, nivolumab is given for a defined period as “adjuvant” therapy to reduce the chance of the cancer returning.
Cancers Nivolumab Treats
Nivolumab has one of the broadest approval lists of any immunotherapy drug. As of 2025, the FDA has approved it for melanoma (both advanced and after surgery), non-small cell lung cancer, malignant pleural mesothelioma, kidney cancer, classical Hodgkin lymphoma, head and neck squamous cell carcinoma, bladder cancer, colorectal cancer with specific genetic features, and liver cancer. For some of these cancers it’s used alone, for others in combination with ipilimumab or chemotherapy, and for several it’s approved in multiple treatment settings.
Biomarker Testing Before Treatment
Not everyone with these cancers will be offered nivolumab. For some indications, particularly lung cancer, your doctor will first test your tumor for PD-L1 expression, the very protein nivolumab’s mechanism revolves around. A pathologist examines a tissue sample and reports a percentage score reflecting how much PD-L1 the tumor cells display. Higher expression generally predicts a stronger response to PD-1 inhibitors. In metastatic lung cancer, for example, nivolumab combined with ipilimumab is specifically approved for tumors expressing PD-L1 at 1% or higher.
For other cancers, different biomarkers matter. Colorectal cancer patients are tested for microsatellite instability or mismatch repair deficiency, genetic features that make tumors particularly responsive to immunotherapy. Your oncologist will determine which tests are needed based on your cancer type and stage.