First-in-human, phase I study of PF-06753512, a vaccine-based immunotherapy regimen (PrCa VBIR), in biochemical relapse (BCR) and metastatic castration-resistant prostate cancer (mCRPC).

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 2612-2612
Author(s):  
Karen A. Autio ◽  
Celestia S. Higano ◽  
Luke T. Nordquist ◽  
Leonard Joseph Appleman ◽  
Tian Zhang ◽  
...  

2612 Background: Therapeutic vaccines targeting PC-associated antigens represent attractive approaches in combination with immune checkpoint inhibitors (ICI). Safety/antitumor activity of PF-06753512 (PrCa VBIR) was evaluated in a phase I, dose-escalation and expansion study in patients (pts) with BCR prior to ADT and in pts with mCRPC either prior to or after failure of novel hormone therapy. PrCa VBIR consists of: 1) priming immunization with a replication-deficient adenoviral vector (AdC68) expressing PSA, prostate-specific membrane antigen and prostate stem cell antigen; 2) boosts with plasmid DNA (pDNA) encoding the same antigens by IM electroporation; 3) ICI given subcutaneously, including anti CTLA-4 antibody tremelimumab (TRM) and anti PD-1 antibody sasanlimab (SSL). Methods: AdC68 ± ICI(s) were given on months (mos) 1 and 5 and pDNA ± ICI(s) on mos 2–4 and 6–8. After 8 mos, maintenance pDNA + ICI(s) were given every 1 or 2 mos. In Part A (6 escalation cohorts), pts with mCRPC received AdC68 (4 or 6x10e11 viral particles) + pDNA 5 mg ± ICIs (TRM alone 80 mg; TRM 40 or 80 mg + SSL 130 or 300 mg). In Part B (3 expansion cohorts), pts with mCRPC received AdC68 6x10e11 + pDNA 5 mg + TRM 80 mg + SSL 300 mg; pts with BCR received similar vector and pDNA + TRM 80 mg ± SSL 130 mg. Primary objectives: Assess overall safety (CTCAE v4.03), determine expansion dose. Secondary objectives: Anti-tumor activity (RECIST v1.1, Prostate Cancer Working Group 3, PSA 50 response) and immune response. (Note: Database remains open, some queries pending). Results: As of Sept 15, 2020, 91 pts were treated in dose-escalation (n=38) and expansion (n=53; BCR=35, mCRPC=18). Immune responses (ELISpot) were positive in some pts. Grade (G) 3 or 4 treatment-related adverse events (TRAEs) developed in 38.5% (35/91) of pts. G5 TRAEs occurred in 2 pts (n=1 G4 myasthenia gravis + G5 pulmonary embolism; n=1 G5 myocarditis). irAEs were more frequent in BCR compared to mCRPC. See the table for efficacy data. Conclusions: Vaccination with PrCa VBIR had a manageable safety profile. TRAEs increased when 2 ICIs were given. Some pts with BCR experienced durable PSA-50 responses without ADT; patients with mCRPC had few objective tumor responses, but had prolonged median rPFS. PrCa VBIR appears to stimulate antigen-specific immunity and results in noticeable antitumor activity, particularly in androgen sensitive disease. Clinical trial information: NCT02616185. [Table: see text]

2010 ◽  
Vol 17 (4) ◽  
pp. 880-887 ◽  
Author(s):  
Dana Rathkopf ◽  
Glenn Liu ◽  
Michael A. Carducci ◽  
Mario A. Eisenberger ◽  
Aseem Anand ◽  
...  

2010 ◽  
Vol 28 (15_suppl) ◽  
pp. 4669-4669
Author(s):  
M. A. Carducci ◽  
M. A. Eisenberger ◽  
S. R. Denmeade ◽  
S. F. Slovin ◽  
A. Jakobovits ◽  
...  

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. TPS174-TPS174
Author(s):  
Jingsong Zhang ◽  
Mark N. Stein ◽  
William Kevin Kelly ◽  
Che-Kai Tsao ◽  
Gerald Steven Falchook ◽  
...  

TPS174 Background: Bispecific antibodies (bsAbs) are emerging as a protein-based therapeutic strategy for directing T-cell-mediated cytotoxicity in a tumor antigen-specific manner, typically by binding to both tumor antigen and the CD3 receptor on T-cells. REGN5678 is a human IgG4-based, first-in-class costimulatory bsAb designed to target prostate tumors by bridging prostate specific membrane antigen expressing tumor cells with the costimulatory receptor, CD28, on T-cells, and providing amplified T-cell receptor-CD3 complex-mediated T-cell activation within the tumor through the activation of CD28 signaling. At the tumor site, REGN5678 may synergize with PD-1 inhibitors. In mouse models, REGN5678 in combination with a PD-1 antibody has improved anti-tumor activity compared with either therapy alone (Waite JC et al. Sci Transl Med. 2020:12;549). Methods: This is an open label, Phase I/II, first-in-human study evaluating safety, tolerability, pharmacokinetics (PK), and anti-tumor activity of REGN5678 alone and in combination with cemiplimab in patients with metastatic castration resistant prostate cancer (mCRPC) who progressed after prior therapy (NCT03972657). For inclusion, patients must have received at least two prior lines of systemic therapy (in addition to androgen deprivation therapy) approved for metastatic and/or castration-resistant disease including a second-generation anti-androgen therapy. REGN5678 is administered weekly; cemiplimab (350 mg) is administered once every 3 weeks. During dose escalation, a 3-week safety lead-in of REGN5678 monotherapy will be administered prior to addition of cemiplimab. Study therapies are administered until disease progression, intolerable adverse events, withdrawal of consent, or study withdrawal criterion is met. The primary objectives in dose escalation are to evaluate safety, tolerability, and PK of REGN5678 alone and in combination with cemiplimab. Expansion cohort(s) will be enrolled once a maximum-tolerated REGN5678/cemiplimab dose is reached, or if a recommended Phase 2 dose or doses have been determined. During the expansion phase, the primary objective is to assess clinical activity, as measured by objective response rate of REGN5678 in combination with cemiplimab per modified Prostate Cancer Working Group 3 criteria. At selected sites, prostate-specific membrane antigen PET/CT scans are performed at baseline and select time points on study. This study is currently open to enrollment. Clinical trial information: NCT03972657.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. TPS5088-TPS5088
Author(s):  
Mark T. Fleming ◽  
Richard Cathomas ◽  
Daniel Peter Petrylak ◽  
Judy Sing-Zan Wang ◽  
Neil Harrison Bander ◽  
...  

TPS5088 Background: Therapeutic advances have recently been achieved for patients with metastatic, castration-resistant prostate cancer (mCRPC) due to abiraterone acetate (ABI) and enzalutamide (ENZ). However, virtually all patients with mCRPC eventually progress in their disease, and further treatment options are limited. Prostate-specific membrane antigen (PSMA) is highly expressed in nearly all prostate cancers, and its expression is highest in mCRPC. MEDI3726 is an antibody-drug conjugate composed of anti-PSMA antibody derived from J591, site-specifically conjugated to the cytotoxic, DNA cross-linking, pyrrolobenzodiazepine dimer. MEDI3726 has demonstrated potent and specific in vitro and in vivo antitumor activity in human prostate cancer-derived preclinical models with different expression levels of PSMA. Methods: This is a first-in-human, phase 1/1b, multicenter, open-label, dose escalation and dose expansion study in patients who have received prior treatment with ABI or ENZ, with or without prior taxane-based chemotherapy in the mCRPC setting (NCT02991911). The primary objectives are to assess safety and tolerability, describe dose-limiting toxicities, and determine the maximum tolerated dose or maximum administered dose of MEDI3726. The secondary objectives are to evaluate MEDI3726 for its antitumor activity (based on a composite response according to RECIST Version 1.1, a reduction in prostate-specific antigen level of 50% or more compared to baseline, or a conversion in the circulating tumor cell count [defined as a reduction from ≥5 cells/7.5 mL blood to < 5 cells/7.5 mL blood]), safety and tolerability in combination with ENZ, pharmacokinetics alone and in combination with ENZ, and immunogenicity. Recruitment is ongoing for this study, which has an estimated total target enrollment of 224 patients. Clinical trial information: NCT02991911.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. TPS5592-TPS5592
Author(s):  
Charles G. Drake ◽  
Jingsong Zhang ◽  
Mark N. Stein ◽  
Yuanfang Xu ◽  
Frank A. Seebach ◽  
...  

TPS5592 Background: Bispecific antibodies (bsAbs) are emerging as a protein-based therapeutic strategy for directing T-cell-mediated cytotoxicity in a tumor antigen-specific manner, typically by binding to both tumor antigen and the CD3 receptor on T cells. REGN5678 is a human IgG4-based, first-in-class costimulatory bsAb designed to target prostate tumors by bridging prostate specific membrane antigen expressing tumor cells with the costimulatory receptor, CD28, on T cells, and providing amplified T-cell receptor-CD3 complex-mediated T-cell activation within the tumor through the activation of CD28 signaling. At the tumor site, REGN5678 may synergize with PD-1 inhibitors. In mouse models, REGN5678 in combination with PD-1 antibody has improved anti-tumor activity compared with either therapy alone (Skokos et al CRI/CICON 2019; oral, session 3). This study evaluates the safety and anti-tumor activity of REGN5678 alone and in combination with cemiplimab in patients with metastatic castration-resistant prostate cancer (mCRPC) who progressed after prior therapy. Methods: This is an open label, Phase I/II, first-in-human study evaluating safety, tolerability, pharmacokinetics (PK), and anti-tumor activity of REGN5678 alone and in combination with cemiplimab in treatment-experienced mCRPC (NCT03972657). For inclusion, patients must have received at least two approved therapies for metastatic disease, including a second-generation hormonal agent. REGN5678 is administered weekly and cemiplimab (350 mg) is administered once every 3 weeks. During dose escalation, a 3-week safety lead-in of REGN5678 monotherapy will be administered prior to the addition of cemiplimab. Study therapies are administered until disease progression, intolerable adverse events, withdrawal of consent, or study withdrawal criterion is met. The primary objectives in dose escalation are to evaluate safety, tolerability, and PK of REGN5678 alone and in combination with cemiplimab. Expansion cohort(s) will be enrolled once a REGN5678/cemiplimab recommended Phase II dose is determined. During the expansion phase, the primary trial objective is to assess clinical activity, as measured by objective response rate of REGN5678 in combination with cemiplimab per modified Prostate Cancer Working Group 3 criteria. This study is currently open to enrollment. Clinical trial information: NCT03972657 .


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