Subcutaneous Immunotherapy in Cancer: Where We Are Now, What It Changes, and What to Watch Next

Subcutaneous (SC) formulations of monoclonal antibodies are rapidly transforming the delivery of cancer immunotherapy. Designed to replace or complement intravenous (IV) administration, SC delivery reduces infusion chair time, improves convenience, and may enhance patient and provider satisfaction while preserving pharmacokinetics (PKs), efficacy, and safety. Recent phase III studies of immune checkpoint inhibitors and bispecific antibodies-including atezolizumab, nivolumab, pembrolizumab, and amivantamab-have consistently demonstrated PK noninferiority and comparable clinical outcomes with IV formulations. Safety profiles are largely unchanged, with immune-related adverse events occurring at similar rates, although mild injection site reactions are more common. Importantly, SC amivantamab has shown a marked reduction in infusion-related reactions relative to IV dosing. Operational studies confirm that SC administration shortens treatment delivery from 30 to 60 minutes to