Table 2.

Challenges and opportunities to improve studies in ABMR.

Challenges	Opportunities
Heterogenous cases with varied clinical outcomes
•Varied baseline DSA quantity •Preexisting versus de novo DSA •ABMR detected via surveillance or indication biopsy	•Plan to enroll patients with a similar risk profile as those included in pilot and early observational studies. •Balance the inclusion of patients with preexisting and de novo DSA. Adjust for whether the ABMR diagnosis was made via indication or surveillance biopsy
Difficult to conduct clinical trials because of low enrollment and need for prolonged follow-up
•The time to graft loss after ABMR detection can be several years. •High risk transplants with DSA and positive crossmatch are done less often making it more difficult to enroll patients in clinical trials. •The downside of improving the homogeneity in the studied patient population is a decrease in patients who meet inclusion criteria. •Patients with chronic ABMR often not found early because these patients may be followed by non-transplant nephrologists and/or do not get surveillance DSA or biopsies	•Develop international consortia. •To account for long follow-up, consider using reliable qualified surrogate endpoints such as slope of eGFR, and plan for long term extension studies to verify results. •Be realistic about enrollment and include centers experienced in transplantation with donor specific antibody. •Develop decentralized clinical trials and partner with local general nephrologists to enroll and identify patients who do not have long term follow-up in an academic medical center. •Consider novel clinical trial design to overcome small patient numbers
Lack of standardized reporting limit the ability to communicate or combine results for meta-analysis
•Key details about DSA, histology, and patient characteristics often missing in the literature	•Collaboration and development of minimum standards for reporting by major transplant groups (e.g., Banff). •Minimal standard reporting consistently followed by industry and enforced by major clinical journals