Bempegaldesleukin
Also known as: BEMPEG, bempegaldesleukin, CD122-biased IL-2, NKTR-214, NKTR‑214, PEG‑IL‑2
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Summary
Bempegaldesleukin (BEMPEG, NKTR‑214) is an investigational, pegylated interleukin‑2 (IL‑2) prodrug designed to boost anti‑tumor immunity. It is being studied in combination with the PD‑1 inhibitor nivolumab for various advanced cancers, including sarcoma, urothelial carcinoma, renal cell carcinoma, and melanoma. The goal is to enhance effector T‑cell and natural‑killer‑cell activity while limiting regulatory T‑cell expansion, thereby improving checkpoint‑inhibitor responses.
Mechanism of Action
Bempegaldesleukin is a PEGylated IL‑2 cytokine that preferentially engages the IL‑2βγ receptor (CD122) rather than the high‑affinity αβγ complex. This CD122 bias drives sustained signaling that expands CD8⁺ cytotoxic T cells and NK cells more than FoxP3⁺ regulatory T cells. By reshaping the tumor microenvironment toward an effector phenotype, it aims to synergize with PD‑1 blockade, which releases inhibitory signals on those same immune cells.
What the Research Shows
Early‑phase data showed modest activity of bempegaldesleukin plus nivolumab in refractory sarcoma, with objective responses in angiosarcoma (3/8) and undifferentiated pleomorphic sarcoma (2/10). A phase II urothelial carcinoma trial in cisplatin‑ineligible patients reported an overall response rate of ~19% and median overall survival of 12.6 months, but the study did not meet its predefined efficacy threshold. In a phase III renal cell carcinoma trial, the combination yielded a lower response rate (23% vs 31% with tyrosine‑kinase inhibitors) and no overall‑survival benefit, though grade 3/4 adverse events were fewer than with TKIs. The pivotal phase III melanoma study (PIVOT IO 001) found the combination inferior to nivolumab alone for response rate (27.7% vs 36%) and progression‑free survival, with higher rates of severe toxicity. Across trials, the regimen was generally tolerable but associated with frequent low‑grade events such as fever and pruritus.
Reported Benefits
Bempegaldesleukin’s CD122‑biased signaling can preferentially expand cytotoxic lymphocytes, offering a mechanistic rationale for enhancing checkpoint‑inhibitor efficacy. Early signals of activity in certain sarcoma subtypes and in urothelial carcinoma suggest potential benefit in selected tumors. Compared with some tyrosine‑kinase inhibitors, the combination produced fewer high‑grade adverse events in renal cell carcinoma, indicating a possibly more favorable safety profile in that context.
Limitations of the Evidence
Phase III trials in melanoma and renal cell carcinoma failed to demonstrate superiority over standard therapies, and the urothelial carcinoma study did not meet its primary efficacy threshold. Responses were modest and inconsistent across tumor types, and increased toxicity was observed versus nivolumab alone in melanoma. Data are limited to early‑phase or single‑arm studies for many indications, and no regulatory approval has been granted. Biomarker analyses remain exploratory, leaving uncertainty about patient selection.
Safety Considerations
All participants in the sarcoma pilot experienced at least one adverse event, and one death was possibly treatment‑related. Common treatment‑related events across studies include fever (pyrexia) and pruritus. Grade 3/4 adverse events occurred in 25.8% of renal cell carcinoma patients receiving the combination versus 56.5% with TKIs, but were higher than with nivolumab alone in melanoma (21.7% vs 11.5%). No new safety signals emerged in the urothelial carcinoma trial, though the overall tolerability was similar to prior studies. Monitoring for immune‑related toxicities and cytokine‑related symptoms is advised.
How It Is Administered
Bempegaldesleukin is administered intravenously, typically every three weeks, often in combination with nivolumab given on the same schedule. The drug is supplied as a pegylated cytokine prodrug formulation designed for controlled release and sustained IL‑2 pathway activation.
Routes of Administration
Goals & Uses
- MelanomaOncologyModerate
- Metastatic melanoma treatmentOncologyModerate
- Regulatory T cell suppression reductionImmunologyModerate
- Renal cell carcinoma treatmentOncologyLow
- Anti-tumor immunity enhancementOncologyModerate
- Urothelial carcinoma treatmentOncologyModerate
- Non‑small cell lung cancerOncologyLow
- anti‑tumor immune activationOncologyModerate
- Renal cell carcinomaOncologyModerate
Contraindications
- Organ transplantationTransplantHigh
- Poor performance status (ECOG ≥2)Clinical StatusModerate
- Severe autoimmune diseaseImmunologicalHigh
- Known hypersensitivity to bempegaldesleukin or its excipientsAllergyHigh
- hypersensitivity to bempegaldesleukin or excipientsAllergyHigh
- Prior severe IL-2 toxicityPrior Adverse ReactionHigh
- Active severe infectionInfectiousHigh
- Active, uncontrolled autoimmune diseaseImmuneModerate
- Active autoimmune diseaseAutoimmunityModerate
Adverse Effects
- Cytokine release syndromeImmunologicUncommonSystemic inflammatory response from immune activation
- Edema/fluid retentionFluid BalanceUncommon
- Flu-like symptoms (fever, chills, fatigue)ConstitutionalCommon
- HypotensionCardiovascularUncommonLow blood pressure
- Fever/chillsConstitutionalCommon
- Rash/skin toxicityDermatologicalCommon
- NauseaGastrointestinalCommonFeeling of sickness or urge to vomit
- FatigueGeneralCommonLow energy or tiredness
- Immune-mediated adverse eventsImmunologicalUncommon
- Rash/pruritusDermatologicCommon
- Infusion-related reactionsHypersensitivityCommon
Drug Interactions
- High‑dose corticosteroidsModerate
- Nivolumab (anti-PD-1)Moderate
- Cytochrome P450 inhibitorsLow
- Ipilimumab (anti-CTLA-4)Moderate
- Pembrolizumab (anti-PD-1)Moderate
- other cytokine therapiesHigh
- CorticosteroidsModerate
- Other cytokine therapies (e.g., IL‑2, IL‑15)High
Population Constraints
- PregnancyReproductive SafetyAbsolute
- Pediatric patientsAgeRelative
- LactationReproductiveRelative
- Pregnant womenReproductiveRelative
- Patients with hepatic or renal impairmentOrgan ImpairmentRelative
- Patients with organ transplantsImmunologicalRelative
Regulatory Status
- European UnionInvestigationalClinical trials ongoing; not authorized.
- United StatesInvestigationalUnder IND; Phase 2/3 trials.
- United KingdomInvestigationalBeing evaluated in NHS-sponsored studies.
In Phase 2/3 trials for several solid tumours; not approved in any jurisdiction as of 2024.
Evidence & Sources
- Journal ArticleModerateD'Angelo SP, et al.2022-01-01T00:00:00.000000Z
- Journal ArticleModerateSiefker-Radtke AO, et al.2025-01-01T00:00:00.000000Z
- Journal ArticleModerateTannir NM, et al.2024-01-01T00:00:00.000000Z
- Journal ArticleModerateKhushalani NI, et al.2020-01-01T00:00:00.000000Z
- Journal ArticleModerateDiab A, et al.2023-01-01T00:00:00.000000Z
- Journal ArticleModerateSiefker-Radtke AO, et al.2022-01-01T00:00:00.000000Z
Frequently Asked Questions
What type of cancer is bempegaldesleukin being tested for?
It is under investigation in combination with nivolumab for several advanced solid tumours, including metastatic sarcoma, urothelial carcinoma, clear‑cell renal cell carcinoma, and unresectable or metastatic melanoma.
How does bempegaldesleukin differ from regular interleukin‑2 therapy?
Unlike native IL‑2, bempegaldesleukin is pegylated and engineered to preferentially bind the CD122 (IL‑2βγ) receptor, which expands cytotoxic T and NK cells while limiting regulatory T‑cell activation, aiming for a more targeted immune boost.
Has bempegaldesleukin been approved for clinical use?
No. All available data are from clinical trials; the compound remains investigational and has not received regulatory approval for any indication.
What are the most common side effects when combined with nivolumab?
The combination frequently causes low‑grade fever and itching. Higher‑grade toxicities, such as severe immune‑related adverse events, occur more often than with nivolumab alone, especially in melanoma trials.
Is there any biomarker that predicts response to bempegaldesleukin?
Exploratory analyses have suggested that higher CD8⁺ T‑cell infiltrates and PD‑1 expression may correlate with better responses, while Hedgehog pathway activity was linked to resistance in sarcoma; however, these findings are preliminary and not validated.
What is Bempegaldesleukin?
Bempegaldesleukin (BEMPEG, NKTR‑214) is an investigational, pegylated interleukin‑2 (IL‑2) prodrug designed to boost anti‑tumor immunity. It is being studied in combination with the PD‑1 inhibitor nivolumab for various advanced cancers, including sarcoma, urothelial carcinoma, renal cell carcinoma, and melanoma. The goal is to enhance effector T‑cell and natural‑killer‑cell activity while limiting regulatory T‑cell expansion, thereby improving checkpoint‑inhibitor responses.
What is Bempegaldesleukin used for?
Bempegaldesleukin is educationally associated with: Melanoma, Metastatic melanoma treatment, Regulatory T cell suppression reduction, Renal cell carcinoma treatment, Anti-tumor immunity enhancement, Urothelial carcinoma treatment, Non‑small cell lung cancer, anti‑tumor immune activation, Renal cell carcinoma. Educational only — not medical advice.
How is Bempegaldesleukin administered?
Recorded routes of administration: Intravenous, Subcutaneous.
What are the potential side effects of Bempegaldesleukin?
Reported adverse effects include: Cytokine release syndrome, Edema/fluid retention, Flu-like symptoms (fever, chills, fatigue), Hypotension, Fever/chills, Rash/skin toxicity, Nausea, Fatigue, Immune-mediated adverse events, Rash/pruritus, Infusion-related reactions. This list is not exhaustive — consult a qualified clinician.
Who should avoid Bempegaldesleukin?
Recorded contraindications: Organ transplantation, Poor performance status (ECOG ≥2), Severe autoimmune disease, Known hypersensitivity to bempegaldesleukin or its excipients, hypersensitivity to bempegaldesleukin or excipients, Prior severe IL-2 toxicity, Active severe infection, Active, uncontrolled autoimmune disease, Active autoimmune disease. Consult a qualified clinician before use.