A new experimental treatment is offering hope for people living with a rare but serious kidney condition called IgA nephropathy. Researchers report that a dual-acting biologic drug, already approved in China for lupus, significantly reduced protein levels in the urine of patients with this kidney disease. This reduction is a key sign that the drug may help protect the kidneys from long-term damage.

In a study published in the New England Journal of Medicine, scientists found that patients who received the drug, known as telitacicept, saw their urinary protein-to-creatinine ratio drop by nearly 59% after 39 weeks of treatment. In comparison, patients who received a placebo injection saw only a 9% decline. The urinary protein-to-creatinine ratio is a standard measure doctors use to track how much protein is leaking into the urine, which is a warning sign of kidney damage.

This article breaks down what the study found, what it means for patients, and what experts say about the future of treatment for this condition.

What Is IgA Nephropathy?

IgA nephropathy, also called Berger’s disease, is a condition where a protein called immunoglobulin A builds up in the kidneys. Immunoglobulin A is normally part of the body’s immune system and helps fight infections. But when too much of it collects in the tiny filters inside the kidneys, it causes inflammation and scarring. Over time, this damage can lead to kidney failure.

Experts consider IgA nephropathy the most common type of primary glomerulonephritis worldwide. Glomerulonephritis is a general term for inflammation of the kidney’s filtering units. The condition is especially concerning because it is one of the leading causes of kidney failure in young adults. In the United States, about 60 out of every 100,000 people have the condition. Rates are somewhat higher in eastern Asia.

For many patients, the disease progresses slowly over years or even decades. Symptoms can include blood in the urine, swelling in the hands and feet, and high blood pressure. But some people have no symptoms at all until the disease is advanced. This makes early detection and effective treatment extremely important.

How This New Drug Works

Telitacicept is what scientists call a dual-acting biologic agent. That means it targets two different parts of the immune system at the same time. Specifically, it blocks two regulatory cytokines: B-cell activating factor, often called BAFF, and a proliferation-inducing ligand, known as APRIL. Both of these cytokines are believed to play a major role in driving the inflammation and protein buildup that damage the kidneys in IgA nephropathy.

By blocking BAFF and APRIL, telitacicept may help reduce the production of abnormal immunoglobulin A and calm the immune system’s attack on the kidneys. This is a more targeted approach than older treatments, which mostly focused on managing symptoms like high blood pressure after the damage had already started.

The drug is already approved in China for treating lupus, another autoimmune disease. Its developer, a company called RemeGen, has begun laying the groundwork for submitting the drug to the U.S. Food and Drug Administration (FDA) for approval in IgA nephropathy.

Study Details: What the Research Found

The study, called TELIGAN, included 318 patients with persistent proteinuria, meaning they had ongoing protein leakage in their urine. Patients were randomly assigned to receive either telitacicept injections or placebo injections once a week for 39 weeks. This was a prespecified interim analysis, meaning the researchers checked the results early to see if the drug was working. The full trial is planned to last for 104 weeks.

Here are the key findings from the study:

• Urinary protein-to-creatinine ratio: Dropped by 58.9% in the telitacicept group, compared to only 8.8% in the placebo group.
• Speed of response: Patients on the active drug saw a 20% drop in the first 4 weeks and a 40% drop by week 13. The placebo group showed almost no change.
• Kidney function: Only 6% of patients on telitacicept saw their estimated glomerular filtration rate (eGFR) fall by 30% or more by week 39. In the placebo group, 27% of patients had that level of decline. eGFR is a key measure of how well the kidneys are filtering waste from the blood.
• Patient profile: Just over half of the participants were women. The average age was about 38 years old. The average disease duration was around 3 years. Mean eGFR at the start was about 75 mL/min/1.73 m², which is in the normal to mildly reduced range. Some 13% of patients had eGFR values between 30 and 45 mL/min/1.73 m², indicating more advanced kidney damage.

The researchers noted that the urinary protein-to-creatinine ratio had not fully plateaued by the 39-week mark, suggesting that the drug’s benefits might continue to grow with longer treatment.

Safety and Side Effects

Overall, telitacicept appeared to be safe in this study. About 90% of patients in the drug group and 79% in the placebo group reported some kind of adverse event. However, serious adverse events were less common in the drug group: 4 patients on telitacicept had serious events, compared to 13 on placebo. None of the serious events in the drug group were considered related to the treatment.

Here are the main side effects noted:

• Injection site reactions: Half of the patients on telitacicept developed reactions at the injection site, including two that were serious. Only 14% of the placebo group had this issue.
• Immunoglobulin levels: About one-quarter of patients on telitacicept had declines in their levels of immunoglobulin G and M, which are other types of antibodies. This happened in almost no one on placebo.
• Weight gain: Nine patients on the active drug gained weight, compared to three on placebo.
• Infections: Infection rates were similar between the two groups.

The researchers pointed out that the study was conducted in China, which is a limitation. The results may not fully apply to other populations. Also, this was a relatively short-term analysis, and longer-term safety data will be needed.

How This Affects Patients

For people living with IgA nephropathy, this study represents a potential new treatment option. Currently, the condition has limited targeted therapies. For many years, treatment focused on controlling blood pressure with medications like ACE inhibitors or angiotensin receptor blockers, and sometimes using steroids to reduce inflammation. But these approaches do not address the underlying immune system problem.

In recent years, the treatment landscape has started to change. In 2024, the FDA approved iptacopan, a complement inhibitor, for IgA nephropathy. Last year, sibeprenlimab, which targets APRIL, was also approved. Other drugs with formal indications for the condition include a delayed-release form of budesonide, the endothelin inhibitor atrasentan, and the endothelin/angiotensin II blocker sparsentan.

Telitacicept is not the only drug targeting BAFF and APRIL. A rival drug called atacicept, which also blocks both cytokines, had phase III trial results reported last year. Its developer has applied for accelerated U.S. approval, which could come within the next few weeks. This means patients may soon have multiple options that target the same underlying disease pathways.

Experts say that having more treatment choices is critical. IgA nephropathy affects people differently, and not every drug works for every patient. Some patients may respond better to one biologic agent than another. Having a range of options allows doctors to tailor treatment to the individual.

What Experts Say

Kidney specialists generally agree that the development of targeted therapies for IgA nephropathy is a major step forward. For decades, the condition was poorly understood and difficult to treat. Now, researchers are unraveling the immune pathways that drive the disease and designing drugs that specifically interrupt those pathways.

Dr. Hong Zhang of Peking University First Hospital in Beijing, the lead author of the study, noted that the rapid and sustained reduction in proteinuria seen with telitacicept is encouraging. Proteinuria is a strong predictor of kidney disease progression, so lowering it is a key treatment goal.

However, experts caution that this is still early data. The full trial will continue to 104 weeks, and the final primary outcome will be the annualized rate of eGFR decline. That will give a clearer picture of whether the drug actually preserves kidney function over the long term, not just reduces protein in the urine.

Some specialists also point out that the drug’s effect on other immunoglobulins needs to be monitored. Lowering immunoglobulin G and M levels could potentially increase the risk of infections over time, although this was not seen in the short-term study.

Practical Takeaways for Readers

If you or a loved one has IgA nephropathy, here is what you should know:

• Talk to your nephrologist: New treatments are emerging, but they are not right for everyone. Your doctor can help you understand whether a biologic therapy like telitacicept or atacicept might be appropriate based on your specific condition.
• Monitor your proteinuria: The urinary protein-to-creatinine ratio is a key marker of disease activity. If your levels are high, it may be time to discuss more aggressive treatment options.
• Stay informed about approvals: The FDA may approve new drugs for IgA nephropathy in the coming months. Keep an eye on trusted health news sources and ask your doctor about new options.
• Understand the limitations: These drugs are not cures. They are designed to slow disease progression and protect kidney function. Lifestyle factors like controlling blood pressure, eating a kidney-friendly diet, and avoiding medications that can damage the kidneys remain important.
• Consider clinical trials: If you have IgA nephropathy and are interested in accessing new treatments, ask your doctor about clinical trials. Many are ongoing, and they offer a chance to receive cutting-edge therapies.

Looking Ahead

The competition among drug developers for IgA nephropathy treatments is heating up. With multiple drugs targeting BAFF and APRIL, as well as other immune pathways, patients may soon have more options than ever before. This is a welcome change for a disease that has historically had few targeted treatments.

For now, the telitacicept study provides strong evidence that blocking these two cytokines can significantly reduce proteinuria in a relatively short time. The full results of the TELIGAN trial, expected in about two years, will show whether this translates into long-term protection of kidney function.

As research continues, patients and doctors alike are watching closely. The goal is clear: to slow or stop the progression of IgA nephropathy and help people avoid the need for dialysis or kidney transplantation. With each new study, that goal moves a little closer to reality.

Source: MedPage Today