Hansa Biopharma announced full results from the 16-HMedIdeS-12 phase 2 trial in patients with antibody mediated rejection (AMR) episodes following a kidney transplant demonstrating that imlifidase significantly reduced donor-specific antibodies (DSAs) within the first five days of treatment. In the trial, the primary endpoint was the maximum reduction in DSA level at any time point during the 5 days following the start of treatment. Patients treated with imlifidase demonstrated a statistically significant reduction of DSAs by 94.4% compared to a 35.6% (p-value: <0.001) reduction in patients who received standard of care (plasma exchange, or PE).

DSA levels subsequently returned to approximately 70% of the initial level in both treatment arms. The secondary endpoint investigated overall kidney function following treatment. The imlifidase arm demonstrated a 74% six-month graft survival and eGFR of 30mL/min/1.73m2. A 100% six-month graft survival and eGFR of 33mL/min/1.73m2 was observed in the PE arm.

Given the heterogeneity of the patient population, the trial was not designed nor sufficiently powered to be able show a statistically significant difference in the secondary outcome measures. Imlifidase demonstrated a safety profile consistent with previous clinical trials. The AMR patient population is heterogeneous, consisting of both chronic patients - those who experience slow rejection after a transplant, and which often results in irreversible damage to the organ - and acute patients who experience AMR early post-transplant.

Additionally, AMR can be driven by a combination of antibodies and T-cells-mediated action (CMR - cell mediated rejection), creating additional complexity when it comes to treatment strategy. Treatment guidelines indicate reduction of DSA levels as one of the main goals of any AMR treatment. To date, there are no approved therapies for the treatment of AMR, and all current treatments including standard of care are used off-label.