ImmunityBio Wins FDA Approval for First IL-15 Superagonist for NMIBC

Pictured: Bladder cancer; iStock_wildpixel

Pictured: 3D artistic illustration of a bladder being afflicted by cancer cells/iStock, wildpixel 

The FDA on Monday greenlit ImmunityBio’s first-in-class IL-15 superagonist nogapendekin alfa inbakicept-pmln, which will now carry the brand name Anktiva, for the treatment of non-muscle invasive bladder cancer.

The approval allows the use of Anktiva with Bacillus Calmette-Guérin (BCG), a vaccine that prevents tuberculosis and other mycobacterial infections, in BCG-unresponsive patients with carcinoma in situ. The treatment can be used in non-muscle invasive bladder cancer (NMIBC) patients with or without papillary tumors. Approximately 80% of new bladder cancer diagnoses are NMIBC, according to ImmunityBio.

Anktiva’s approval used the FDA’s Assessment Aid, which is a voluntary submission that applicants can file to facilitate and expedite the review process. ImmunityBio expects to make Anktiva available in the U.S. by mid-May 2024, the company said.

Patrick Soon-Shiong, ImmunityBio’s global chief scientific and medical officer, in a statement called Monday’s approval “an important milestone” not only for the company but also for NMIBC patients. “By orchestrating the innate and adaptive immune system and driving long-term complete remission, Anktiva has the potential to play a key role as the immunotherapy beyond checkpoints in multiple tumor types,” Soon-Shiong said.

Anktiva is a therapeutic fusion protein that combines a mutant version of the IL-15 cytokine with an IL-15 receptor fusion protein. This structure allows Anktiva to stimulate the proliferation of CD8+ T cells and natural killer cells while also activating CD4+ T helper cells, which boosts the division of memory killer T cells. Anktiva also sidesteps the activation of regulatory T cells.

“This novel mechanism of action, which mimics the biology of the dendritic cell, begins the evolution of immunotherapy beyond T cells alone,” Soon-Shiong said.

Anktiva previously won the FDA’s Breakthrough Therapy designation for NMIBC. However, in May 2023, the regulator rejected ImmunityBio’s Biologics License Application, citing problems documented during a pre-license inspection of a third-party manufacturer.

ImmunityBio resubmitted the application in October 2023, which the regulator considered as a complete response.

Monday’s approval is backed by data from the Phase II/III QUILT-3.032 study, an open-label, single-arm, multicenter study with 190 participants, of whom 77 had evaluable data. Patients received maintenance treatment with Anktiva and BCG for up to 18 months. The complete response rate was 62% for these patients, with duration of response exceeding 47 months at the November 2023 cut-off.

QUILT-3.032 is ongoing, with the final median duration of response yet to be determined. Additional updates from the trial will be presented at the upcoming annual conference of the American Urological Association in May 2024.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. Reach out to him on LinkedIn or email him at or

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