N-803 (Anktiva)

N-803 is a cancer drug, used under close monitoring. There is no case for seeking it, or any IL-15 product, to slow aging.

What it is

IL-15 is a signalling molecule (cytokine) that acts as the main survival and growth signal for natural killer (NK) cells and memory CD8⁺ T-cells, the "killer" T-cell type.^[1] NK cells and memory T-cells are the immune cells that hunt infected and cancerous cells, and they are among the cells that age worst. N-803, formerly called ALT-803, is an IL-15 "superagonist": a complex engineered to give a stronger and longer-lasting IL-15 signal than the natural molecule. Its role in immune aging is covered on Immunosenescence.

Approved for one bladder cancer

N-803, sold as Anktiva, was approved in the US in 2024 for one form of bladder cancer. It is high-risk cancer that has not invaded the muscle wall, includes an early flat form called carcinoma in situ, and no longer responds to the standard treatment, BCG (a weakened relative of the tuberculosis bacterium, instilled into the bladder). Anktiva is given into the bladder alongside BCG. In the single-arm, company-funded trial behind the approval, the cancer cleared in about six in ten patients (62% of 77 in the US Food and Drug Administration's analysis).^[2][3] Because it is given into the bladder, its safety record says little about IL-15 given into the bloodstream.

Trials in other cancers

• Lung cancer. In a phase 1b trial pairing N-803 with the immunotherapy drug nivolumab in metastatic lung cancer, 6 of 21 patients had a partial tumour response (29%, 95% confidence interval 11–52). The range means the true rate could plausibly lie anywhere from about one in ten to about one in two, and the figure was worked out after the fact rather than as a prespecified endpoint.^[4]
• Relapse after a stem-cell transplant. In the first-in-human study, 33 patients who had relapsed after a stem-cell transplant were treated, and responses were seen in 19% of evaluable patients.^[5]

The safety record is better than its reputation

It is worth being precise, because the safety record is often reported more alarmingly than it reads.

• The lung-cancer trial recorded no dose-limiting toxicities and never reached a maximum tolerated dose.^[6]
• The transplant-relapse study identified no dose-limiting toxicity, and no patient met criteria for severe cytokine-release syndrome or capillary-leak syndrome. What did occur was fever and chills with intravenous dosing, an injection-site rash in almost every patient dosed under the skin, and transient high blood pressure in 83% at the highest doses.^[7]

The serious harms belong to free recombinant IL-15, the plain molecule rather than the superagonist complex. In its first-in-human trial, 18 cancer patients received daily intravenous doses. Severe drops in blood pressure, a fall in platelets and rises in liver enzymes forced a tenfold dose reduction, and the best response achieved was stable disease. Even there the authors recorded only modest capillary leak, in explicit contrast to high-dose interleukin-2, the drug whose reputation IL-15 tends to inherit.^[8]

Why it is not a longevity drug

• No trial has tested raising IL-15 in healthy people.
• More is not better. When human NK cells are kept in IL-15 continuously in the lab, they first ramp up and then suffer a metabolic collapse and lose their ability to kill; a break of a few days between exposures prevented it.^[9]
• IL-15 can drive disease. Chronically high local IL-15 is a driver of autoimmune disease, most clearly in celiac disease, where gluten-triggered IL-15 in the gut lining breaks immune tolerance and destroys the intestinal surface.^[10]

The broader class of unproven anti-aging drugs is covered under geroprotectors.

What to do

1. If you have the form of bladder cancer described above, N-803 is an approved option to discuss with your urologist.
2. Otherwise, don't seek IL-15 drugs or supplements for aging. Nothing supports it, and the lab evidence points the other way.

Further reading

• Chamie K, et al. IL-15 Superagonist NAI in BCG-Unresponsive Non-Muscle-Invasive Bladder Cancer. NEJM Evid 2023.^[11]
• Wrangle JM, et al. ALT-803, an IL-15 superagonist, in combination with nivolumab in patients with metastatic non-small cell lung cancer: a non-randomised, open-label, phase 1b trial. Lancet Oncol 2018.^[12]
• Romee R, et al. First-in-human phase 1 clinical study of the IL-15 superagonist complex ALT-803 to treat relapse after transplantation. Blood 2018.^[13]
• Conlon KC, et al. Redistribution, hyperproliferation, activation of natural killer cells and CD8 T cells, and cytokine production during first-in-human clinical trial of recombinant human interleukin-15 in patients with cancer. J Clin Oncol 2015.^[14]
• Felices M, et al. Continuous treatment with IL-15 exhausts human NK cells via a metabolic defect. JCI Insight 2018.^[15]