Bone mineral density changes following immune checkpoint inhibitor therapy: insights from a case series analysis

Brief rationale: The use of ICIs is increasing rapidly. Limited studies support potential effects on bone health.

Osteoporotic patients demonstrated a 6% and 17% reduction in femoral and lumbar spine BMD, respectively. Paper significance: This is a real-world data record of the effect of one-year ICI treatment on skeletal health.

Immune checkpoint inhibitors (ICIs) are used as a treatment for various malignancies, resulting in the occurrence of a plethora of immune-related adverse events (irAEs). An increasing interest has emerged on the possible effects of these drugs on the skeleton, predominantly osteoporotic fractures, although bone health studies are scarce.

Our study analyzed retrospectively the percentage of the alteration of the bone mineral density (BMD) evaluated by Dual Energy X-Ray Absorptiometry (DXA) scan in 15 oncological patients before and after the administration of ICIs, as well as the occurrence of osteoporotic fractures, within a median follow-up period of 12 months.

Patients with normal baseline BMD presented a median femoral and lumbar BMD reduction of 0.15% and 0.10%, respectively. Patients with a baseline BMD in favor of osteopenia exhibited no alterations in the femoral BMD and a median 0.07% reduction in the lumbar BMD. Patients with baseline osteoporosis demonstrated a femoral and lumbar BMD reduction of 6% and 17.30%, respectively. No osteoporotic fracture was demonstrated during the median follow-up period of 12 months.

ICIs effect on bone metabolism of oncological patients remains undefined. In our cohort, patients with normal BMD and osteopenia did not present a significant change in the BMD after a median follow-up of 12 months. However, patients with baseline osteoporosis were the most affected in both sites. Larger prospective studies are needed to replicate our findings and to define the impact of these drugs on the skeleton.