A favorable response rate to immune checkpoint inhibitors was observed in 56.0% of patients in the group with normal baseline vitamin D levels or normal levels obtained with vitamin D supplementation, compared with 36.2% in the group with low vitamin D levels without supplementation.

Patients with advanced skin cancer should make extra efforts to maintain normal vitamin D levels when receiving immune checkpoint inhibitors, according to a study in CANCER.

To see whether levels of vitamin D might impact the effectiveness of immune checkpoint inhibitors, investigators analyzed the blood of 200 patients with advanced melanoma both before and every 12 weeks during immunotherapy treatment.

A favorable response rate to immune checkpoint inhibitors was observed in 56.0% of patients in the group with normal baseline vitamin D levels or normal levels obtained with vitamin D supplementation, compared with 36.2% in the group with low vitamin D levels without supplementation, the study showed. Progression‐free survival—the time from treatment initiation until cancer progression—in these groups was 11.25 and 5.75 months, respectively.

“Of course, vitamin D is not itself an anti-cancer drug, but its normal serum level is needed for the proper functioning of the immune system, including the response that anti-cancer drugs like immune checkpoint inhibitors affect,” says lead author Łukasz Galus, MD, of Poznan University of Medical Sciences, in Poland, in a news release. “In our opinion, after appropriately randomized confirmation of our results, the assessment of vitamin D levels and its supplementation could be considered in the management of melanoma.”