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Investigating a new treatment for advanced solid tumors

IL Believe: A Phase 1/2, Open-label, Dose Escalation and Dose Expansion Study to Investigate the Safety and Tolerability of TransCon IL-2 β/γ Alone or in Combination With Pembrolizumab, TransCon TLR7/8 Agonist, or Other Anticancer Therapies, in Adult Participants With Locally Advanced or Metastatic Solid Tumor Malignancies

Phase1; Phase2 Interventional Ascendis Pharma A/S · NCT05081609

This study is testing a new treatment for adults with advanced solid tumors to see if a new drug can work better alone or with other cancer therapies.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment345 (estimated)
Ages18 Years and up
SexAll
SponsorAscendis Pharma A/S Industry-sponsored
Drugs / interventionsimmunotherapy, radiation
Locations67 sites (Los Angeles, California and 66 other locations)
Trial IDNCT05081609 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates the safety and tolerability of TransCon IL-2 β/γ, an investigational drug, either alone or in combination with pembrolizumab and other anticancer therapies in adults with locally advanced or metastatic solid tumors. It is a first-in-human, open-label study that includes both dose escalation and dose expansion phases. The trial aims to leverage the unique pharmacokinetic profile of TransCon technology to enhance the therapeutic index of IL-2 therapy, which is crucial for immune system modulation.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18 and older with histologically confirmed locally advanced or metastatic solid tumors that cannot be treated with curative intent.

Not a fit: Patients with solid tumors that can be treated with curative intent or those with ECOG performance status greater than 2 may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could provide a new therapeutic option for patients with advanced solid tumors, potentially improving their outcomes.

How similar studies have performed: Other studies have shown promise with similar immunotherapy approaches, but this specific combination is novel and untested.

Eligibility criteria

Show full inclusion / exclusion criteria 
Key Inclusion Criteria:

* At least 18 years of age, or country defined local legal age
* Demonstrated adequate organ function at screening
* Life expectancy \>12 weeks as determined by the Investigator
* Female and male participants of childbearing potential who are sexually active must agree to use highly effective methods of contraception
* Participants must have histologically confirmed locally advanced, recurrent, or metastatic solid tumor malignancies that cannot be treated with curative intent (surgery or radiotherapy), with the exception of the neoadjuvant cohorts
* Part 1 and Part 2: Eastern Cooperative Oncology Group (ECOG) performance status 0, 1, or 2
* Part 3 and Part 4: Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
* Participants who have undergone treatment with anti-PD-1, anti-PD-L1, or anti-cytotoxic T-lymphocyte-associated protein (CTLA-4) antibody must have a washout of at least 4 weeks from the last dose and evidence of disease progression per investigator assessment before Cycle 1 Day 1 (C1D1) with the exception of the neoadjuvant cohorts
* Participants who have previously received an immunotherapy prior to C1D1 must have any immune-related toxicities resolved to ≤Grade 1 or baseline (prior to the immunotherapy) to be eligible, with the exception of participants on well controlled physiologic endocrine replacement
* Part 3: Neoadjuvant cohorts: participants must have completely resectable disease

Key Exclusion Criteria:

* Symptomatic central nervous system metastases and/or carcinomatous meningitis
* Active autoimmune diseases, regardless of need for immunosuppressive treatment, with the exception of participants well controlled on physiologic endocrine replacement
* Any uncontrolled bacterial, fungal, viral, or other infection
* Significant cardiac disease
* A marked clinically significant baseline prolongation of QT/QTc interval (e.g., repeated demonstration of a QTc interval \>480 ms) \[CTCAE Grade 1\]) using Fridericia's QT correction formula
* Positive for human immunodeficiency virus (HIV) or has known active hepatitis B or C infection
* Known hypersensitivity to any study treatment(s) used in the specific study part/cohort
* Participants who have been previously treated with IL-2 or IL-2 variants (all participants)
* Systemic immunosuppressive treatment with the exception for patients on corticosteroid taper (for example, for chronic obstructive pulmonary disease exacerbation).
* Vaccination with live, attenuated vaccines within 4 weeks of C1D1
* Treatment with any other anti-cancer systemic treatment (approved or investigational) or radiation therapy within 4 weeks of C1D1
* Part 3: Other active malignancies within the last 2 years
* Women who are breastfeeding or have a positive serum pregnancy test during screening

Where this trial is running

Los Angeles, California and 66 other locations

+17 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Advanced Solid TumorLocally Advanced Solid TumorMetastatic Solid TumorPlatinum-resistant Ovarian CancerPost Anti-PD-1 Melanoma2L+ Cervical CancerNeoadjuvant MelanomaNeoadjuvant Non-Small Cell Lung Cancer
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.