Phase 1 Study Evaluating Safety and Tolerability of SL-T10, GX-I7, and Pembrolizumab Triple Combination in mCRPC.

A Phase 1, Multi-center, Open-label, Dose-escalating Study to Evaluate the Safety and Tolerability of Triple Combination Regimen of SL-T10, GX-I7 and Pembrolizumab in Patients With Metastatic Castration-resistant Prostate Cancer (mCRPC)

The purpose of this study is to evaluate the efficacy and safety of SL-T10 and GX-I7 or SL-T10, GX-I7 and pembrolizumab in patients with metastatic castration-resistant prostate cancer (mCRPC).

Study Overview

• Status: Recruiting
• Conditions: Metastatic Castration-resistant Prostate Cancer (mCRPC)
• Intervention / Treatment: Biological: SL-T10; Biological: GX-I7; Biological: Pembrolizumab

Detailed Description

The purpose of this study is to evaluate the safety, tolerability, and preliminary efficacy of SL-T10, GX-I7, and pembrolizumab in combination in patients with metastatic castration-resistant prostate cancer (mCRPC).

• Study Type: Interventional
• Enrollment (Estimated): 78
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Yong Bok Seo, phD; Phone Number: 82-2-6098-2816; Email: clinical@slvaxigen.com

Study Locations

• Korea, Republic of
  • Seoul, Korea, Republic of
    • Recruiting
    • Seoul National University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Male patients 19 years of age or older at the date of written informed consent.
2. Patients with histopathologically or cytologically confirmed adenocarcinoma of the prostate, documented by bone or soft tissue lesions.
3. Patients with castration-resistant prostate cancer with a blood testosterone level of less than 50 ng/dL at the screening visit.
4. patients with metastatic castration-resistant prostate cancer (mCRPC) who meet the following criteria (based on PCWG3.0 modified RECIST 1.1)

1) Prior taxane therapy for metastatic prostate cancer or confirmed refusal or inadequacy of such therapy 2) Patients who have received prior docetaxel and at least one of the following agents: abiraterone acetate or enzalutamide before or after docetaxel treatment 3) Patients with progression of prostate cancer during/after prior therapy, in the investigator's judgment, with either of the following, in the internal or external castration state

1. PSA progression defined as at least 2 PSA level increases (≥1 week interval between each test) and a PSA level of ≥2 ng/mL at Screening
2. Advanced soft tissue disease as defined by RECIST 1.1
3. Progressive bone disease defined as ≥2 new lesions on bone scan (per PCWG3)

5. Patients who are on androgen deprivation therapy (ADT) of any kind (patients who have not undergone bilateral orchiectomy must begin internal castration therapy, such as luteinizing hormone-releasing hormone (LHRH) agonists, LHRH antagonists, or anti-androgenic agents, at least 4 weeks prior to Baseline and must continue for the entire duration of the study)

Exclusion Criteria:

1. patient has an active autoimmune disease or is receiving systemic steroid therapy or in immunosuppressive status.
2. Patient has history of chemotherapy, radiation chemotherapy, biological therapy, immunotherapy, or radiation therapy within 4 weeks prior to the screening visit (In case of nitrosoureas or mitomycin, 6 weeks prior to the screening visit)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cohort S1; SL-T10 (3mg, multiple injections, IM), GX-I7 (320 ug 2 injections, IM)	Biological: SL-T10; A therapeutic DNA vaccine containing three prostate cancer-specific antigen genes and genetic adjuvants; Biological: GX-I7; A T-cell growth factor
Experimental: Cohort S2; SL-T10 (6mg, multiple injections, IM), GX-I7 (320 ug 2 injections, IM)	Biological: SL-T10; A therapeutic DNA vaccine containing three prostate cancer-specific antigen genes and genetic adjuvants; Biological: GX-I7; A T-cell growth factor
Experimental: Cohort a'; SL-T10 (3mg, multiple injections, IM), GX-I7 (320 ug 2 injections, IM), Pembrolizumab	Biological: SL-T10; A therapeutic DNA vaccine containing three prostate cancer-specific antigen genes and genetic adjuvants; Biological: GX-I7; A T-cell growth factor; Biological: Pembrolizumab; An immune check point inhibitor
Experimental: Cohort A; SL-T10 (6mg, multiple injections, IM), GX-I7 (320 ug 2 injections, IM), Pembrolizumab	Biological: SL-T10; A therapeutic DNA vaccine containing three prostate cancer-specific antigen genes and genetic adjuvants; Biological: GX-I7; A T-cell growth factor; Biological: Pembrolizumab; An immune check point inhibitor
Experimental: Cohort B; SL-T10 (6mg, multiple injections, IM) GX-I7 (720 ug 2 injections, IM) Pembrolizumab	Biological: SL-T10; A therapeutic DNA vaccine containing three prostate cancer-specific antigen genes and genetic adjuvants; Biological: GX-I7; A T-cell growth factor; Biological: Pembrolizumab; An immune check point inhibitor
Experimental: Cohort C; SL-T10 (6mg, multiple injections, IM), GX-I7 (960 ug 2 injections, IM), Pembrolizumab	Biological: SL-T10; A therapeutic DNA vaccine containing three prostate cancer-specific antigen genes and genetic adjuvants; Biological: GX-I7; A T-cell growth factor; Biological: Pembrolizumab; An immune check point inhibitor

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants with treatment-emergent adverse events (TEAEs)	Number of participants with treatment-emergent adverse events (TEAEs)	Baseline to 23 weeks
Number of participants with Serious adverse events (SAEs) as assessed by CTCAE v5.0	Number of participants with Serious adverse events (SAEs) as assessed by CTCAE v5.0	Baseline to 48 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
PSA response rate	% patients with a reduction in PSA level from baseline by 50% or greater	Baseline to 48 weeks
PSA progression free survival	The interval from the date of randomisation to the date of first evidence of PSA progression or death from any cause, whichever occurred first.	Baseline to 48 weeks
Radiographic progression free survival	The interval from the date of disease progression on CT and/or Tc bone scan or death from any cause, whichever occurred first.	Baseline to 48 weeks
Change of induced T-cell responses for SL-T10 vaccine	Vaccine-induced T-cell responses assessed by immunoassays in peripheral blood	Baseline to 48 weeks

Collaborators and Investigators

• Sponsor: SL VAXiGEN
• Investigators: Principal Investigator: Cheol Kwak, MD, phD, Seoul National University Hospital; Principal Investigator: Chang Wook Jeong, MD, phD, Seoul National University Hospital

Study record dates

Study Major Dates

• Study Start (Actual): October 17, 2022
• Primary Completion (Estimated): October 31, 2024
• Study Completion (Estimated): October 31, 2024

Study Registration Dates

• First Submitted: March 19, 2024
• First Submitted That Met QC Criteria: March 27, 2024
• First Posted (Actual): April 3, 2024

Study Record Updates

• Last Update Posted (Actual): April 3, 2024
• Last Update Submitted That Met QC Criteria: March 27, 2024
• Last Verified: March 1, 2024

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms; Urogenital Neoplasms; Neoplasms by Site; Genital Neoplasms, Male; Prostatic Diseases; Urogenital Diseases; Male Urogenital Diseases; Genital Diseases, Male; Genital Diseases; Prostatic Neoplasms; Molecular Mechanisms of Pharmacological Action; Antineoplastic Agents; Antineoplastic Agents, Immunological; Immune Checkpoint Inhibitors; Pembrolizumab
• Other Study ID Numbers: SL-T10-001_P1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No