Evaluating the long-term effectiveness and safety of injections under the skin of daratumumab versus intravenous infusions for patients with relapsed or refractory multiple myeloma.

This study reported the final effectiveness and safety of subcutaneous (SC) injections versus intravenous (IV) infusions of daratumumab (Darzalex) in patients with relapsed or refractory multiple myeloma (MM). The data showed that daratumumab SC injections were as effective and caused fewer side effects than IV infusions over the long term in these patients.

Multiple myeloma (MM) is a type of cancer that comes from blood cells called plasma cells. A high number of patients with MM experience relapse (the tumor grows after treatment) or are refractory (not responsive to the treatment) to standard treatment. Currently, the treatment strategies for r/r MM are based on the different combinations of conventional drugs and novel drugs.

Daratumumab is a biological therapy that targets MM cells and helps to destroy them. It is given by IV infusion in hospitals or medical centers. The first infusion takes up to 7 hours and the following infusions take 3 to 4 hours. This practice is time-consuming, can affect patients’ quality of life, and increases the risks of developing side effects. Daratumumab SC (under the skin) injections may be a more feasible alternative. A previous short-term study showed that SC injections were as effective as IV infusions and caused fewer side effects. However, it is unknown if over the long-term SC injections are as effective and safe as IV infusions of daratumumab in patients with r/r MM.

The study involved 522 patients with r/r MM. Patients were randomly assigned into 2 groups. Group 1 included 263 patients who received daratumumab by SC injection. Group 2 included 259 patients who received daratumumab by IV infusion. The average follow-up time was 29.3 months.

The overall response rate (partial or complete disappearance of cancer cells) was 43.7% for group 1 compared to 39.8% for group 2.

The average survival without cancer worsening was 5.6 months for group 1 compared to 6.1 months for group 2. The average overall survival was 28.2 months for group 1 compared to 25.6 months for group 2.

The rate of infusion-related reactions was lower in group 1 (12.7%) compared to group 2 (34.5%). The administration time was shorter in group 1 (3-5 minutes) compared to group 2 (3-7 hours).

The rate of severe treatment-related side effects was similar between the 2 groups (50.8% for group 1 vs 52.7% for group 2). The most common side effects were low blood cell counts.

This study concluded that daratumumab SC injections were as effective and caused fewer side effects than IV infusions over the long term in patients with r/r MM.

This study was funded by Janssen, the manufacturer of daratumumab.