Opdivo (nivolumab) stays active in your body for months after your last infusion, and its effects on your immune system can persist even longer. What happens next depends on why you stopped, how well your cancer responded, and how long you were treated. For most people, stopping means a transition into close monitoring rather than an immediate change in how you feel day to day.
How Long Opdivo Stays in Your Body
Opdivo has a half-life of about 27 days, meaning it takes that long for half the drug to clear from your bloodstream. After each half-life, the remaining amount drops by half again. As a general rule, a drug is considered fully eliminated after about five half-lives. For Opdivo, that works out to roughly four to five months after your final infusion before the drug itself is essentially gone.
But the drug’s absence doesn’t mean its effects disappear on the same timeline. Opdivo works by releasing the brakes on your immune system, specifically by blocking a protein called PD-1 that tumors use to hide from T-cells. Once those T-cells have been “woken up,” some of them convert into memory cells that can continue recognizing and attacking cancer without the drug’s help. This is why some patients maintain lasting responses long after stopping treatment.
Whether Your Cancer Stays Under Control
This is the biggest concern for most people stopping Opdivo, and the answer varies significantly depending on how well the drug was working when you stopped. A large trial in advanced lung cancer (CheckMate 153) compared patients who continued Opdivo beyond one year with those who stopped at the one-year mark. Among patients whose tumors had shrunk (partial or complete response), those who continued treatment stayed progression-free for a median of 31 months compared to about 10.6 months for those who stopped. Two-year survival rates were also higher in the group that kept going: roughly 73% versus 61%.
Interestingly, for patients whose disease had merely stabilized rather than actively shrinking, stopping at one year made much less difference. Their progression-free survival was nearly identical whether they continued or not (about 12 months versus 9 months), and overall survival was similar in both groups. This suggests that the benefit of continuing treatment is strongest when the drug is actively shrinking tumors.
In a real-world study of people with metastatic melanoma who stopped immunotherapy, about 32% experienced disease progression after a median follow-up of nearly 21 months. Among those who did progress, it happened at a median of 8.5 months after stopping, though some didn’t see recurrence until nearly three years later. That wide range is part of why ongoing surveillance matters so much.
Side Effects Can Appear Months Later
One of the more counterintuitive aspects of stopping Opdivo is that new side effects can surface well after your last dose. These delayed immune-related events (sometimes called DIREs) occur because the immune activation triggered by the drug outlasts the drug itself. Your revved-up immune system can mistakenly target healthy tissues weeks or months down the road.
The median time for these delayed reactions is about six months after the last dose, but they’ve been documented as late as 15 months out. In published case reports, one patient developed lung inflammation, liver inflammation, and kidney problems 142 days after stopping nivolumab. Another developed liver inflammation 436 days, more than 14 months, after their final infusion.
The true frequency of these delayed events is hard to pin down. More than 80% of clinical trials only tracked serious side effects for less than 90 days after the last dose, meaning many delayed reactions were simply never captured in the data. The types of delayed side effects mirror the ones that occur during treatment: inflammation of the lungs, liver, kidneys, thyroid, or pituitary gland. If you develop new symptoms in the months after stopping, particularly shortness of breath, persistent fatigue, unexplained jaundice, or unusual headaches, these warrant prompt evaluation even if your last infusion was months ago.
Hormonal Changes May Be Permanent
Some immune-related side effects resolve on their own or with treatment, but damage to hormone-producing glands can be irreversible. The thyroid and pituitary gland are particularly vulnerable. If Opdivo triggered hypothyroidism or pituitary inflammation during treatment, you may need hormone replacement therapy indefinitely, regardless of whether you continue the drug. Monitoring of cortisol and thyroid hormone levels is recommended at regular intervals both during and after treatment ends.
What Monitoring Looks Like After Stopping
Expert guidelines recommend continued surveillance for at least 12 months after discontinuing immunotherapy. This typically includes periodic imaging (CT scans, and brain MRI if symptoms warrant it) to watch for cancer recurrence, along with blood work to check organ function and hormone levels. The exact schedule varies by cancer type and your individual risk, but the principle is the same: stopping the drug doesn’t mean stopping the watch.
Scans serve a dual purpose during this period. They detect any return of cancer early enough that retreatment can be considered, and they can also catch signs of immune-related inflammation in organs like the lungs before symptoms become severe.
Restarting Opdivo If Cancer Returns
If your cancer does progress after stopping, restarting Opdivo is possible but the results tend to be more modest the second time around. A phase II study of nivolumab retreatment in lung cancer patients who had initially responded but later relapsed found an objective response rate of only about 8.5%. That’s considerably lower than typical first-time response rates, though some patients do still benefit. The likelihood of responding to retreatment is generally better if you originally stopped because of side effects rather than because the cancer was already growing through the drug.
Why Duration Varies by Cancer Type
There’s no single standard duration for Opdivo treatment. The FDA-approved prescribing information specifies different timelines depending on the situation. For advanced melanoma or previously treated lung cancer, treatment continues until the disease progresses or side effects become unacceptable, with no preset stopping point. For adjuvant melanoma treatment (given after surgery to reduce recurrence risk), the course is capped at one year. For first-line lung cancer treatment combined with ipilimumab, the upper limit is two years in patients without progression.
These differences reflect the varying levels of evidence for each cancer type and setting. The decision to stop is always individualized, weighing how well the cancer has responded, how long you’ve been on treatment, and what side effects you’re experiencing. Patients with a complete response (no detectable cancer on scans) are the strongest candidates for a treatment break, though even in this group, some oncologists prefer to continue for a defined period before stopping.