Daxdilimab Succeeds in Lupus Trial, Bemarituzumab Cancer Study Paused

A new phase 2 clinical trial has shown promising results for daxdilimab in treating discoid lupus erythematosus (DLE), a chronic autoimmune skin disease. Simultaneously, a separate trial evaluating bemarituzumab for gastric cancer has been halted, according to recent reports.

Daxdilimab Shows Promise in Discoid Lupus

Daxdilimab, a human monoclonal antibody (mAb), is designed to target a protein called immunoglobulin-like transcript 7, found specifically on plasmacytoid dendritic cells (pDCs). These cells play a key role in the type I interferon response, which drives disease activity in lupus. The phase 2 trial, as detailed in research presented at the ACR Convergence 2024 conference on November 17, 2024, evaluated the efficacy and safety of daxdilimab in patients with DLE that had not responded to standard treatments.

The study, identified as NCT05591222, was a double-blind, randomized, placebo-controlled trial. This means participants were randomly assigned to receive either daxdilimab or a placebo, and neither the participants nor the researchers knew who was receiving which treatment until the study was completed. The trial is currently evaluating participants with moderate-to-severe active primary DLE.

While specific results regarding the degree of improvement were not detailed in the provided information, the initial report indicates that daxdilimab hit the primary endpoint in the phase 2 trial. This suggests the drug demonstrated a statistically significant benefit compared to placebo in treating discoid lupus.

Systemic Lupus Erythematosus Trial Results

A separate phase 2 trial investigating daxdilimab for the treatment of Systemic Lupus Erythematosus (SLE) did not meet its primary endpoint. According to a report from the Lupus Foundation of America, the trial did not obtain a significant difference in disease activity compared to placebo. This indicates that, in this particular study, daxdilimab did not demonstrate a statistically significant improvement in SLE symptoms compared to a placebo.

The SLE trial involved 214 participants who were randomized to receive either daxdilimab administered every four weeks (Q4W), every twelve weeks (Q12W), or a placebo every four weeks for 48 weeks. Approximately 10.3% of participants discontinued the trial, with the most common reason being withdrawal by the patient. Baseline characteristics were comparable across all groups.

Daxdilimab works by targeting pDCs through antibody-dependent cellular cytotoxicity. SLE is characterized by periods of flares and remission, and is an autoimmune disease affecting multiple organ systems. Type I interferon, secreted by activated pDCs, is believed to contribute to the disease’s progression.

Bemarituzumab Trial Halted in Gastric Cancer

In contrast to the positive findings for daxdilimab in discoid lupus, a phase 2 trial evaluating bemarituzumab for gastric cancer has been stopped. The reason for the halt was not specified in the provided information, but it suggests the drug did not demonstrate sufficient efficacy or safety to continue development for this indication.

Looking Ahead

The contrasting outcomes of these two trials highlight the complexities of drug development and the challenges of treating autoimmune diseases and cancer. The success of daxdilimab in the discoid lupus trial offers hope for patients with this difficult-to-treat condition. Further research will be needed to confirm these findings and to determine the long-term safety and efficacy of daxdilimab.

The failure of the bemarituzumab trial in gastric cancer underscores the high attrition rate in cancer drug development. While disappointing, these setbacks are a necessary part of the process of identifying effective treatments.

As of today, February 4, 2026, the development of daxdilimab continues to be a significant area of interest for Amgen, particularly in the field of lupus treatment. The company is also continuing to explore other potential applications for its pipeline of investigational drugs.