Presenter: Muh Geot Wong, MBBS, PhD, Concord Repatriation General Hospital, Concord, New South Wales, Australia
Long-term effect of oral methylprednisolone on kidney outcomes in patients with IgAN: TESTING-ON, a post-trial observational study. Abstract SA-OR092. Presented November 8, 2025.
Among patients with high-risk immunoglobulin A (IgA) nephropathy, a course of oral methylprednisolone has a beneficial effect that is sustained during long-term follow-up, an investigator reported at American Society of Nephrology Kidney Week 2025.
The positive impacts on kidney failure and related outcomes persisted at a median follow-up of 6.4 years, according to results of the TESTING ON study, presented at the conference by Mut Geot Wong, MBBS, PhD.
The trial builds on the findings from the TESTING (Therapeutic Evaluation of Steroids in IgA Nephropathy Global) trial, published in 2022 in JAMA.
“The data from the TESTING and TESTING ON provide important information on safety and efficacy that enables an informed choice for clinicians and patients,” Dr. Wong said in an interview.
As previously reported in TESTING, methylprednisolone, given in full or reduced doses, significantly reduced the risk of kidney failure and a composite kidney outcome of a 40% decline in estimated glomerular filtration rate (eGFR) from baseline, kidney failure (dialysis or transplantation), or kidney disease-related death.
However, whether those benefits would be maintained over time was unknown. Accordingly, Dr. Wong and colleagues conducted the follow-up TESTING ON trial to understand whether the effects would continue, both overall and by dose.
In an oral presentation, Dr. Wong described findings from the observational post-trial follow-up of the TESTING study. Of 365 eligible participants from TESTING, 211 (58%) consented to participate.
At a median follow-up of 6.4 years, 93 participants in the methylprednisolone group and 109 in the placebo group reached the primary endpoint of TESTING ON, which was kidney failure or death due to kidney disease. That difference was significant, with a hazard ratio of 0.66 (95% confidence interval 0.50–0.88, P = .0049).
The effect of treatment was comparable across prespecified patient subgroups, according to the investigator.
Effects were also maintained across most secondary outcomes, which included death due to kidney disease, annual eGFR decline, and time-averaged proteinuria on 24-hour urine collection, as well as a composite endpoint that included kidney failure, eGFR decreases, and all-cause death.
Baseline characteristics of the TESTING ON cohort were comparable to those of the 503 participants who originally underwent randomization in TESTING, Dr. Wong reported.
Taken together, these findings confirm the beneficial effect of the corticosteroid methylprednisolone on kidney failure and other kidney-related outcomes persist over time, according to Dr. Wong.
“Notably, the benefit is consistent in both the full- and reduced- dose cohort, and at all time points through the entire duration of the follow-up,” he said in the interview.
According to Dr. Wong, methylprednisolone is an important treatment option that can be beneficial regardless of patient access to newer targeted therapies for IgA nephropathy.
“While new treatments for IgA nephropathy are being developed and approved, they remain out of reach for a large part of the world’s population, especially in regions where IgA nephropathy is highly prevalent,” he said.
Disclosures
Muh Geot Wong, MBBS, PhD and coauthors disclosed commercial support from Pfizer (initial seed funding for the TESTING trial).
References
Wong MG, Lv J, Bao Y, et al. Long-term effect of oral methylprednisolone on kidney outcomes in patients with IgAN: TESTING-ON, a post-trial observational study [abstract]. Presented at: American Society of Nephrology Kidney Week 2025; November 6–9, 2025; Houston, TX.
Lv J, Wong MG, Hladunewich MA, et al. Effect of oral methylprednisolone on decline in kidney function or kidney failure in patients with IgA nephropathy: the TESTING randomized clinical trial. JAMA 2022; 327(19):1888–1898. doi:10.1001/jama.2022.5368