Antibody CC-1 in Men With Biochemical Recurrence of Prostate Cancer

Phase I Study to Evaluate the Safety, Tolerability and Preliminary Efficacy of the Bispecific Antibody CC-1 in Men With Biochemical Recurrence of Prostate Cancer

Antibody CC-1 in Men With Biochemical Recurrence of Prostate Cancer (NCT05646550) is a Phase 1 interventional studying Prostate Cancer Recurrent, sponsored by University Hospital Tuebingen. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

This trial is a phase I open-label, single center study designed to evaluate the safety, tolerability and preliminary efficacy of the bispecific prostate specific membrane antigen (PSMA) and cluster of differentiation protein 3 (CD3) antibody CC-1 in men with biochemical recurrence (BCR) of prostate cancer (PC). The PSMA binder in CC-1 reacts with tumor cells and also binds to tumor vessels, thereby allowing for a dual mode of anti-cancer action. CC-1 was developed in a novel format, which not only prolongs serum half-life, but most importantly reduces off-target T-cell activation with accordingly reduced side effects. The study entails a part I (dose escalation part) to identify the maximally tolerated dose of CC-1, which then will be further evaluated in part II of the study (dose expansion part). After application of two low doses as safety steps in the first cycle, CC-1 will be applied twice weekly for three consecutive weeks within 4 week cycles as a short-term intravenous infusion (3 hours). The planned trial ultimately shall define the recommended phase II dose (RP2D) of CC-1 in the disease setting of BCR of PC.

What Stage of Research Is This?

Phase 1 trials test a new treatment for the first time in humans, focusing on safety, dosing, and how the body processes the drug. For Prostate Cancer Recurrent, a Phase 1 study typically enrolls a small number of participants — often healthy volunteers or patients who have exhausted standard treatment options. Phase 1 results determine whether a treatment moves into larger Phase 2 efficacy studies.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 56 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Prostate Cancer Recurrent subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Who May Qualify: - Written willing to sign a consent form - Patient is able to understand and comply with the protocol for the duration of the study including undergoing treatment and scheduled visits and examinations - Men aged 18 and above - Earlier histologic diagnosis of prostatic adenocarcinoma - Low risk of rapid disease progression, defined as: \- PSA-detection Time (DT) \> 1 year AND pathological International Society of Urological Pathology (ISUP) grade \< 4 for men with prior radical prostatectomy or Interval to biochemical recurrence \> 18 months and biopsy ISUP grade \< 4 for men with prior radiation therapy - Biochemical recurrence (BCR) in compliance with the following 3 conditions: - after having finished last definitive treatment - PSA ≥0.2 ng/mL or PSA \> nadir + 2 ng/mL (after definitive RT), with two increasing PSA values prior to study treatment - no distant metastasis upon PSMA- positron emission tomography (PET) imaging - Eastern Cooperative Oncology Group (ECOG) Performance Status ≤ 1 - Male patients with partners of child-bearing potential, who are sexually active, must agree to the use of one highly effective form of contraception and one barrier method. This should be started from the signing of the willing to sign a consent form and continue throughout period of taking study treatment and for 4 months after the last dose of study drug - Adequate bone marrow, renal, and hepatic function defined by laboratory tests within 21 days prior to study treatment: - blood count (hemoglobin) at least 9 g/dl (Transfusion of packed red blood cells prior to enrolment allowed) - Neutrophil count ≥ 1,500/mm3 - Platelet count ≥ 100,000/µl - Bilirubin ≤ 1.5 x upper limit of normal (ULN) - alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 x ULN - gamma-glutamyl-transferase (γ-GT) ≤ 2.5 x ULN - prothrombin time (PT) - international normalised ratio (INR) / partial thromboplastin time (PTT) ≤ 1.5 x ULN - Creatine kinase ≤ 2.5 x ULN ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: * Written informed consent * Patient is able to understand and comply with the protocol for the duration of the study including undergoing treatment and scheduled visits and examinations * Men aged 18 and above * Earlier histologic diagnosis of prostatic adenocarcinoma * Low risk of rapid disease progression, defined as: \- PSA-detection Time (DT) \> 1 year AND pathological International Society of Urological Pathology (ISUP) grade \< 4 for men with prior radical prostatectomy or Interval to biochemical recurrence \> 18 months and biopsy ISUP grade \< 4 for men with prior radiation therapy * Biochemical recurrence (BCR) in compliance with the following 3 conditions: * after having finished last definitive treatment * PSA ≥0.2 ng/mL or PSA \> nadir + 2 ng/mL (after definitive RT), with two increasing PSA values prior to study treatment * no distant metastasis upon PSMA- positron emission tomography (PET) imaging * Eastern Cooperative Oncology Group (ECOG) Performance Status ≤ 1 * Male patients with partners of child-bearing potential, who are sexually active, must agree to the use of one highly effective form of contraception and one barrier method. This should be started from the signing of the informed consent and continue throughout period of taking study treatment and for 4 months after the last dose of study drug * Adequate bone marrow, renal, and hepatic function defined by laboratory tests within 21 days prior to study treatment: * Hemoglobin ≥ 9 g/dl (Transfusion of packed red blood cells prior to enrolment allowed) * Neutrophil count ≥ 1,500/mm3 * Platelet count ≥ 100,000/µl * Bilirubin ≤ 1.5 x upper limit of normal (ULN) * alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 x ULN * gamma-glutamyl-transferase (γ-GT) ≤ 2.5 x ULN * prothrombin time (PT) - international normalised ratio (INR) / partial thromboplastin time (PTT) ≤ 1.5 x ULN * Creatine kinase ≤ 2.5 x ULN * Serum creatinine ≤ 1.5 mg/dl or creatinine clearance ≥ 60 ml/min Exclusion Criteria: * PSA \>5 ng/ml. * For men with prior radical prostatectomy: * PSA-DT \< 1 year or * pathological ISUP grade 4-5 * For men with prior radiation therapy: * Interval to biochemical recurrence \< 18 months or * biopsy ISUP grade 4-5 * Other malignancy within the last 2 years except: adequately treated non-melanoma skin cancer and low-grade non-muscle invasive papillary bladder cancer. * Concurrent or previous treatment within 30 days in another interventional clinical trial with an investigational anticancer therapy * Patients who are receiving androgen-deprivation therapy. * Patients who have received prior Androgen Deprivation Therapy (ADT) are not eligible with the exception of those that received ADT ≤ 36 months in duration and ≥9 months before enrolment and administered only in the neoadjuvant/adjuvant setting. * Castrate level of serum testosterone \<50 ng/dL at screening. * History of HIV infection * Viral active or chronic hepatitis (HBV or HCV) * Ongoing autoimmune disease * Current relevant central nervous system pathology (e.g. seizure, paresis, aphasia, cerebrovascular ischemia/hemorrhage, severe brain injuries, dementia, Parkinson's disease, cerebellar disease, organic brain syndrome, psychosis, coordination or movement disorder) * Therapeutic anticoagulation * Non-controlled hypertension, defined as mean blood pressure values in 24-hours blood pressure measurement of \>130 mmHg or \>90 mmHg for systolic or diastolic, respectively * Heart failure defined as New York Heart Association (NYHA) III/IV * Severe obstructive or restrictive ventilation disorder * Known intolerance to CC-1 or other immunoglobulin drug products as well as hypersensitivity to any of the excipients present in CC-1

Treatments Being Tested

DRUG

CC-1 Infusion

Short term (3h) infusion of CC-1

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

University Hospital Tuebingen

Tübingen, Germany

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT05646550), the sponsor (University Hospital Tuebingen), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT05646550 clinical trial studying?

Who can participate in NCT05646550?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT05646550?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT05646550. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT05646550. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.