# Bempegaldesleukin

Source: https://onco.cc/drugs/bempegaldesleukin/  
OnCo record `bempegaldesleukin` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Bempegaldesleukin was a re-engineered interleukin-2 meant to be a safer version of a famous old immunotherapy. It added nothing to nivolumab in three phase 3 trials.

## Summary

Bempegaldesleukin is a PEGylated IL-2 prodrug biased toward the CD122 receptor to expand CD8 T cells over regulatory T cells. Phase 1/2 PIVOT-02 with nivolumab reported high response rates in melanoma. In 2022, PIVOT IO-001 (melanoma), PIVOT-09 (RCC), and PIVOT-10 (urothelial) all failed to improve response, PFS, or OS over nivolumab alone; BMS and Nektar ended the collaboration (BMS had paid $1.85B upfront in 2018).

Lesson: single-arm combination response rates in melanoma are unreliable because nivolumab alone already produces them; biological rationale (Treg sparing) did not translate.

## Fields

- Kind: Treatment
- Status: negative
- Last checked: 2026-09-06
- Tags: failure; lesson:phase-2-mirage
- Code: NKTR-214, bempeg
- Modality: Engineered cytokine (PEGylated IL-2)
- Mechanism: IL-2 with releasable PEG chains; preferential CD122 (IL-2Rβγ) engagement.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Bempegaldesleukin
- PIVOT IO-001 (J Clin Oncol 2023): https://ascopubs.org/doi/10.1200/JCO.23.00172

## Connected records

- cancers: [Bladder & urothelial cancer](https://onco.cc/cancers/urothelial/), [Melanoma](https://onco.cc/cancers/melanoma/), [Renal cell carcinoma](https://onco.cc/cancers/rcc/)
- technologies: [Cytokines & engineered cytokines](https://onco.cc/technologies/cytokine-therapy/)
- drugs: [Nivolumab](https://onco.cc/drugs/nivolumab/)
- companies: [Bristol Myers Squibb](https://onco.cc/companies/bms/), [Nektar Therapeutics](https://onco.cc/companies/nektar-therapeutics/)
- trials: [A Study of Bempegaldesleukin (NKTR-214: BEMPEG) in Combination With Nivolumab Compared With the Investigator's Choice of a Tyrosine Kinase Inhibitor (TKI) Therapy (Either Sunitinib or Cabozantinib Monotherapy) for Advanced Metastatic Renal Cell Carcinoma (RCC)](https://onco.cc/trials/nct03729245/), [A Study of NKTR-214 Combined With Nivolumab vs Nivolumab Alone in Participants With Previously Untreated Inoperable or Metastatic Melanoma](https://onco.cc/trials/nct03635983/), [Study to Compare Adjuvant Immunotherapy of Bempegaldesleukin Combined With Nivolumab Versus Nivolumab After Complete Resection of Melanoma in Patients at High Risk for Recurrence](https://onco.cc/trials/nct04410445/)
- bottlenecks: [Failures are hidden](https://onco.cc/bottlenecks/b-negative-results/)
- pathways: [T-cell exhaustion](https://onco.cc/pathways/t-cell-exhaustion/)
- targets: [IL2RB](https://onco.cc/targets/il2rb/)

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