A randomized trial shows that administering cancer immunotherapy before 3pm can nearly double survival time for patients with non-small cell lung cancer. Researchers found significant benefits from aligning treatment with circadian rhythms during the initial cycles. This marks the strongest evidence yet for chronotherapy in oncology.
Cancer treatments timed to the body's internal clock may offer a simple way to improve outcomes, according to a pioneering study published in Nature Medicine. Led by Francis Lévi at Paris-Saclay University in France, the research involved 210 patients with non-small cell lung cancer. Participants received four doses of checkpoint inhibitors—either pembrolizumab or sintilimab—combined with chemotherapy.
Half the group got their immunotherapy before 3pm, followed shortly by chemotherapy, while the other half received it later in the day. This schedule applied only to the first four cycles of immunochemotherapy; subsequent treatments were untimed. The team, including Yongchang Zhang from Central South University in China, tracked patients for an average of 29 months after the initial dose.
Results revealed a stark difference: those treated before 3pm survived an average of 28 months, compared to 17 months for the later group. "The effects are absolutely huge," Lévi said. "It’s a nearly doubling in survival time."
Pasquale Innominato from the University of Warwick in the UK praised the trial's design, calling it "the strongest evidence for causality." He noted that such impacts rival those of newly licensed drugs. The benefits likely stem from T-cells, the immune cells targeted by checkpoint inhibitors, clustering near tumors in the morning before dispersing into the bloodstream later.
Prior observational studies hinted at these patterns, but this is the first randomized-controlled trial confirming chronotherapy's role. Experts suggest exploring even narrower timing windows, like around 11am, and extending timed cycles beyond four. Individual factors, such as whether patients are morning people or night owls, could also influence optimal schedules. While promising for lung cancer, applicability to other immunotherapy-responsive tumors—like those in skin or bladder—remains to be tested, though it may not help non-responsive types such as prostate or pancreatic cancers.
