Why Timing Matters in Immunotherapy
- Dr. Lena Suhaila
- Jun 3
- 3 min read
The Clock and the Cure: How Timing Affects Immunotherapy in Lung Cancer
A new look at cancer treatment
Immunotherapy has changed the way we treat advanced lung cancer. In particular, checkpoint inhibitors have helped many people with non small cell lung cancer live longer by unlocking the immune system’s ability to fight cancer.
But why do some people respond better than others? A new study suggests that one overlooked factor may be the answer: the time of day.
This research, presented at the 2025 American Society of Clinical Oncology conference, looked at how the timing of treatment affects survival in patients with advanced non small cell lung cancer.
What the study looked at
The study followed 362 people with advanced non small cell lung cancer who were treated with immune checkpoint inhibitors such as anti PD1 or anti PD L1 therapies.
Researchers recorded the time of day each patient received treatment, grouping them into three categories:
Morning group: most infusions before 12 PM
Afternoon group: most infusions after 12 PM
Mixed group: no consistent timing
They then tracked how long patients lived after starting treatment.
What they found
The timing of treatment made a major difference.
Patients who received most of their immunotherapy infusions in the afternoon had a significantly shorter overall survival compared to those treated in the morning.
The difference in survival was not subtle. Afternoon treatment was associated with a 60 percent higher risk of death than morning treatment.
This held true even after adjusting for factors like age, sex, cancer stage, and treatment type.
Why does timing matter
The body follows a natural rhythm across every twenty four hour cycle. This rhythm, known as the circadian clock, influences how alert we are, how we digest food, and how the immune system functions.
T cells, the immune cells targeted by checkpoint inhibitors, appear to be more responsive earlier in the day. Delivering immunotherapy during this time may give the immune system a stronger push to fight cancer.
This idea is called chronotherapy, matching treatment to the body’s internal timing. This study is one of the clearest examples yet that time of day is not just a detail. It is part of the treatment.
What this means for patients
If these findings are confirmed in further studies, something as simple as scheduling treatment in the morning could help patients with lung cancer live longer.
This is a low cost and low risk adjustment. It does not involve changing the drug, the dose, or the delivery. Just the time.
Next steps for cancer care
This study raises an important question for the future. Should we routinely tailor cancer treatments not just to the type of cancer, but also to the body’s natural rhythms?
The results suggest the answer may be yes.
Future clinical trials should include time of day as a variable, and cancer centers may one day build their schedules around the body’s biology.
Conclusion
For people with advanced non small cell lung cancer, the time of day when immunotherapy is given can strongly affect outcomes. Morning treatment may give the immune system a better chance to fight the disease.
Healing is not only about the medicine we use. It is also about when we give it. This study offers a reminder that the body has a rhythm, and working with that rhythm may be a key to better outcomes.
ASCO 2025 Abstract 8516
Title: "Circadian timing of immune checkpoint inhibitor therapy is associated with survival outcomes in patients with metastatic melanoma"
Authors: David Q. Wang et al.
Presented at: American Society of Clinical Oncology Annual Meeting 2025