NCT03881488

Study of CTX-471 as a Monotherapy or in Combination With Pembrolizumab in Patients Post PD-1/PD-L1 Inhibitors in Metastatic or Locally Advanced Malignancies

Completed Phase 1 Last updated 17 April 2026

What this trial tests

Phase 1 trial testing CTX-471 in Locally Advanced Solid Tumor in 100 participants. Completed in 21 May 2025.

Timeline

17 May 2019

Primary endpoint
21 May 2025

21 May 2025

Quick facts

Lead sponsor	Compass Therapeutics
Phase	Phase 1
Status	Completed
Study type	INTERVENTIONAL
Allocation	non randomized
Design	sequential
Masking	none
Primary purpose	treatment
Enrollment	100
Start date	17 May 2019
Primary completion	21 May 2025
Estimated completion	21 May 2025
Sites	10 locations across United States

Drugs / interventions tested

• CTX-471 — full drug profile →
• Pembrolizumab (KEYTRUDA®) — full drug profile →

Conditions studied

• Locally Advanced Solid Tumor — all drugs for Locally Advanced Solid Tumor →
• Metastatic Cancer — all drugs for Metastatic Cancer →
• Non-small Cell Lung Cancer — all drugs for Non-small Cell Lung Cancer →
• Small Cell Lung Cancer — all drugs for Small Cell Lung Cancer →

Sponsor

Compass Therapeutics — full company profile →

Who can join

18 and older, any sex, with Locally Advanced Solid Tumor or Metastatic Cancer. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

This is a Phase 1, open-label, first-in-human study of CTX-471 administered as a monotherapy or in combination with pembrolizumab in patients with metastatic or locally advanced malignancies that have progressed while receiving an approved PD-1 or PD-L1 inhibitor. The study will be conducted in 2 treatment arms (Monotherapy Arm 1 and Combination Arm 2). Each arm will have two parts: Part 1 Dose Escalation and Part 2 Dose Expansion.

Publications & conference data

8 peer-reviewed publications reference this trial (live from Europe PMC):

1. T-cell agonists in cancer immunotherapy.
   Choi Y, Shi Y, Haymaker CL, Naing A, et al · · 2020 · cited 90× · PMID 33020242 · DOI 10.1136/jitc-2020-000966
2. The emerging landscape of novel 4-1BB (CD137) agonistic drugs for cancer immunotherapy.
   Claus C, Ferrara-Koller C, Klein C. · · 2023 · cited 65× · PMID 36727218 · DOI 10.1080/19420862.2023.2167189
3. 4-1BB immunotherapy: advances and hurdles.
   Singh R, Kim YH, Lee SJ, Eom HS, et al · · 2024 · cited 50× · PMID 38172595 · DOI 10.1038/s12276-023-01136-4
4. The PD-L1/4-1BB Bispecific Antibody-Anticalin Fusion Protein PRS-344/S095012 Elicits Strong T-Cell Stimulation in a Tumor-Localized Manner.
   Peper-Gabriel JK, Pavlidou M, Pattarini L, Morales-Kastresana A, et al · · 2022 · cited 44× · PMID 35121624 · DOI 10.1158/1078-0432.ccr-21-2762
5. Antibody-Targeted TNFRSF Activation for Cancer Immunotherapy: The Role of FcγRIIB Cross-Linking.
   Liu L, Wu Y, Ye K, Cai M, et al · · 2022 · cited 15× · PMID 35865955 · DOI 10.3389/fphar.2022.924197
6. Efficacy of NSCLC Rechallenge with Immune Checkpoint Inhibitors following Disease Progression or Relapse.
   Livanou ME, Nikolaidou V, Skouras V, Fiste O, et al · · 2024 · cited 13× · PMID 38539530 · DOI 10.3390/cancers16061196
7. Anti-4-1BB immunotherapy enhances systemic immune effects of radiotherapy to induce B and T cell-dependent anti-tumor immune activation and improve tumor control at unirradiated sites.
   Martin AL, Powell C, Nagy MZ, Innamarato P, et al · · 2023 · cited 9× · PMID 36469096 · DOI 10.1007/s00262-022-03325-y
8. Targeting 4-1BB for tumor immunotherapy from bench to bedside.
   Wang YT, Ji WD, Jiao HM, Lu A, et al · · 2022 · cited 6× · PMID 36189243 · DOI 10.3389/fimmu.2022.975926