Advanced Solutions: RNAi Therapies and Transplantation Strategies

When conventional treatments like hyperhydration and Vitamin B6 are not enough to protect the kidneys, advanced therapies provide new ways to address the disease at its source. In the past, the only way to address the metabolic defect in Primary Hyperoxaluria was a liver transplant. Today, RNA interference (RNAi) therapies and specialized transplant strategies are changing the outlook for many families ^[1][2].

Precision Medicine: RNAi Therapies

RNAi therapies are a major breakthrough in PH treatment. Unlike traditional medicines that treat symptoms, RNAi therapies work like a “molecular silencer.” They send a signal to the liver to stop producing the enzymes that create excess oxalate ^[1][3].

• Lumasiran: This is the first approved RNAi therapy for PH1. It silences an enzyme called glycolate oxidase ^[1]. In clinical trials, lumasiran reduced 24-hour urinary oxalate by an average of 65% in six months ^[4].
• Nedosiran: This therapy targets a different enzyme called lactate dehydrogenase, which is the very last step in oxalate production ^[5]. While it has shown significant success in lowering oxalate for patients with PH1, research has not yet shown a consistent effect for those with PH2, and it may be investigational depending on your age and location ^[5][6].

These medications are typically given as an injection under the skin every month or every three months. For many, they can stabilize kidney function and may even improve nephrocalcinosis (calcium deposits in the kidney) over time, though reversal of damage and long-term eGFR preservation are not guaranteed ^[7][8]. Treatment requires specialist monitoring and can cause mild injection-site reactions. Always check the specific regulatory approval in your jurisdiction, as eligibility depends on subtype, kidney function, and age.

Intensive Dialysis: Protecting the Whole Body

If kidney function drops significantly, standard dialysis is often not enough for a person with PH. Because the liver continues to pump out oxalate 24/7, a normal dialysis schedule (usually 3 days a week) cannot keep up ^[9][10].

• The 30 μmol/L Threshold: Experts consider a plasma oxalate (blood level) of 30 μmol/L to be a critical risk threshold for systemic oxalosis ^[2]. While this is an important marker, the exact timing and intensity of intensive hemodialysis—which may be up to 6 or 7 days a week—is determined by a metabolic nephrology team based on your eGFR trend, symptoms, and transplant plan ^[2].
• Preventing “Oxalosis”: The goal of this aggressive schedule is to keep blood levels low enough to help prevent systemic oxalosis (crystals depositing in the heart, bones, and eyes) ^[2][11].
• Why Peritoneal Dialysis is Limited: While peritoneal dialysis (done at home through the abdomen) can be helpful, it is usually not powerful enough on its own to remove the massive amounts of oxalate produced in advanced PH ^[9].

The Transplant Decision Tree

Choosing the right type of transplant is one of the most important decisions a PH patient and their care team will make. The goal is to replace the failing kidneys while also addressing the liver’s overproduction of oxalate ^[12][13]. This involves balancing operative risks, lifelong immunosuppression, and the fact that a transplant does not immediately reverse existing systemic deposits.

1. Combined Liver-Kidney Transplant (CLKT): This remains an established option for patients with PH1 who do not respond to Vitamin B6 ^[12][2]. By replacing the liver, you correct the metabolic defect and stop the overproduction entirely.
2. Kidney-Alone Transplant: This is historically risky because the old liver will quickly flood the new kidney with oxalate ^[14]. However, it is an evolving, highly selected strategy that may now be considered for two specific groups:
   • B6 Responders: Those whose oxalate is perfectly controlled by Vitamin B6 ^[12].
   • RNAi-Supported Patients: Patients who show a massive, stable reduction in oxalate while on RNAi therapies ^[13][15].
3. Sequential Transplant: In some cases, a patient may receive a liver transplant first to lower their oxalate levels, followed by a kidney transplant later once the “oxalate stores” in their body have cleared ^[12][16].

A Critical Note on Continuity: If your specialist selects a kidney-only transplant and you rely on RNAi therapy to protect it, that therapy must be uninterrupted. Missing doses could allow oxalate levels to spike, potentially damaging the new kidney ^[17][13]. Always ensure your insurance and care team have a rock-solid plan for maintaining these medications through the transplant transition.