BACKGROUND:Metastatic castration-resistant prostate cancer (mCRPC) has a poor prognosis, necessitating the investigation of novel treatments and targets. This study evaluated JNJ-70218902 (JNJ-902), a T-cell redirector targeting transmembrane protein with epidermal growth factor-like and 2 follistatin-like domains 2 (TMEFF2) and cluster of differentiation 3, in mCRPC. PATIENTS AND METHODS:Patients who had measurable/evaluable mCRPC after at least one novel androgen receptor-targeted therapy or chemotherapy were eligible. Participants received subcutaneous JNJ-902 0.3, 1.0, 1.5, 3.0, or 6.0 mg once weekly (QW) or 2.0, 3.0, 4.0, or 6.0 mg biweekly (Q2W). Study objectives included assessment of safety, pharmacokinetics, immunogenicity, and preliminary efficacy. RESULTS:Eighty-two participants were enrolled to receive at least one dose of JNJ-902 (QW; n = 38; Q2W; n = 44). Median duration of treatment was 1.91 (0.0-19.4) months across dosing groups. All participants experienced at least one treatment-emergent adverse event (TEAE) and 76 (92.7%) experienced treatment-related TEAEs. Fourteen participants (17.1%) experienced a TEAE that led to study discontinuation, of which 3 (3.7%) were related to JNJ-902. Dose-limiting toxicities were observed in 2 participants (2.4%). Five participants (15.2%) with measurable disease had a confirmed partial response and 10 participants (12.2%) had ≥50% decrease from baseline prostate-specific antigen levels. Clinical activity was not dose related and no clear exposure-response relationship was observed. CONCLUSIONS:In this study, dose escalation was limited by emerging dose-limiting toxicities. Although a recommended phase II dose was not determined, findings indicate TMEFF2 to be a potential target in mCRPC that warrants further investigation.

5017 Background: Human kallikrein 2 (encoded by the KLK2 gene and hereafter referred to as KLK2) is a novel target expressed on PC cells with limited normal tissue expression. Pasritamig is a first-in-class T-cell-redirecting bispecific antibody that simultaneously binds KLK2 on PC cells and CD3 receptor complexes on T cells. We report dose escalation and expansion results from a first-in-human study (NCT04898634) evaluating pasritamig in pts with mCRPC. Methods: Pasritamig target doses (TDs) were escalated from 0.5-2000 mg SC and 150-900 mg IV QW-Q6W, with various step-up (SU) dosing schedules. Pre-medication with dexamethasone (16 mg) was required in SU and 1 st TD. The primary objective was to determine the safety and RP2D. Secondary objectives included preliminary assessment of antitumor activity. Results: As of October 7, 2024, 174 pts (median [range] age 69 [36-89] years) had received ≥1 pasritamig dose (Table). Pts had a median of 4 prior therapies (range 1-13; 99.4% ARPI, 78.2% taxane chemotherapy, 17.2% lutetium Lu 177 vipivotide tetraxetan). There were no pasritamig-related deaths. One pt experienced a DLT of transient Gr 3 ALT/AST elevation after 50 mg SU2 SC administration. While most pts reported ≥1 TRAE (82.2% overall; 68.1% IV; 92.2% SC), these were mostly low grade, with only 9.2% of pts (6.9% IV; 10.8% SC) experiencing a Gr ≥3 TRAE. In the RP2D safety population (n=45; 3.5 mg [Day 1], 18 mg [Day 8], 300 mg Q3W or Q6W IV), the most common TRAEs were infusion-related reactions (22.2%; Gr 1/2), fatigue (15.6%; Gr 1/2), and CRS (8.9%; all Gr 1, no tocilizumab was administered), no TRAEs led to treatment discontinuation, no ICANS was observed, and 2 serious TRAEs (Gr 1 CRS) were reported. In the RP2D efficacy population (n=33; 3.5 mg [Day 1], 18 mg [Day 8], 300 mg Q6W IV), PSA50 was 42.4% (14/33) and median rPFS was 6.77 (95% CI 2.89, NE) months with 39.4% of pts ongoing (13/33). ORR in the 85 pts with measurable disease was 16.1% (n=5/31) in pts with lymph node +/- bone and 3.7% (n=2/54) in pts with visceral disease, with a median DOR of 11.27 (95% CI 3.58, NE) months. Conclusions: Pasritamig was very well tolerated (<10% of pts experienced CRS [all Gr1] at the RP2D) with promising antitumor activity, demonstrating proof of concept for KLK2 as a target amenable to T-cell redirection. These results address an unmet need for a targeted T-cell based therapy that is safe to administer in an outpatient setting with clinically meaningful benefit in mCRPC. Phase 3 trials are planned. Clinical trial information: NCT04898634 . TotalN=174 SCn=102 IVn=72 RP2Dn=45 a TRAEs leading to treatment discontinuation, n (%) 1 (0.6) 1 (1.0) 0 0 Gr ≥3 TRAEs, n (%) 16 (9.2) 11 (10.8) 5 (6.9) 2 (4.4) CRS, n (%) 43 (24.7) 31 (30.4) 12 (16.7) 4 (8.9) Gr 1 37 (21.3) 28 (27.5) 9 (12.5) 4 (8.9) Gr 2 6 (3.4) 3 (2.9) 3 (4.2) 0 Radiographic PFS, months, median (95% CI) 4.40 (3.35, 6.47) 4.07 (2.79, 4.93) 5.88 (3.15, NE) 6.77 (2.89, NE) b a RP2D safety pop.=TD 300 mg Q3W/Q6W. b RP2D efficacy pop.=TD 300 mg Q6W (n=33).

PURPOSE:We report phase I trial results for pasritamig, a first-in-class, T-cell-engaging bispecific antibody targeting human kallikrein 2 (KLK2) expressed on the surface of prostate cancer (PC) cells. METHODS:Participants had metastatic castration-resistant PC and ≥1 prior therapy. Pasritamig was escalated from 0.5 mg to 2,000 mg for subcutaneous administration and from 150 mg to 900 mg for intravenous (IV) administration at dosing frequencies ranging from once every week to once every 6 weeks with different step-up dosing schedules. The primary objectives were to determine safety and the recommended phase II dose (RP2D) of pasritamig. Secondary objectives included preliminary assessment of antitumor activity. RESULTS:One hundred seventy-four participants received pasritamig, with a median of 4 prior lines of systemic therapy. Treatment-related adverse events (TRAEs) occurred in 144 of 174 (82.8%) participants, with 17 of 174 (9.8%) experiencing grade ≥3 TRAEs. The RP2D was determined to be 3.5 mg (day 1), 18 mg (day 8), 300 mg (day 15), and then 300 mg IV once every 6 weeks. In the RP2D safety population (n = 45), infusion-related reactions (11/45, 24.4%), fatigue (7/45, 15.6%), cytokine release syndrome (CRS; 4/45, 8.9%, all grade 1), and lipase increase (4/45, 8.9%) were the most frequent TRAEs; all were grade 1 or 2. In the RP2D efficacy population (n = 33), median radiographic progression-free survival was 7.85 (95% CI, 2.89 to not estimable) months, and 14 of 33 (42.4%) participants achieved a ≥50% decrease from baseline in prostate-specific antigen. CONCLUSION:Pasritamig demonstrated a favorable safety profile with very low rates of CRS and could be safely administered in an outpatient setting. Preliminary antitumor activity demonstrated proof of concept for KLK2 as a target in PC, warranting further development of pasritamig.

Erdafitinib, a selective and potent oral pan-FGFR inhibitor, is metabolized mainly through CYP2C9 and CYP3A4 enzymes. This phase 1, open-label, single-sequence, drug-drug interaction study evaluated the pharmacokinetics, safety, and tolerability of a single oral dose of erdafitinib alone and when co-administered with steady state oral carbamazepine, a dual inducer of CYP3A4 and CYP2C9, in 13 healthy adult participants (NCT04330248). Compared with erdafitinib administration alone, carbamazepine co-administration decreased total and free maximum plasma concentrations of erdafitinib (Cmax) by 35% (95% CI 30%-39%) and 22% (95% CI 17%-27%), respectively. The areas under the concentration-time curve over the time interval from 0 to 168 hours, to the last quantifiable data point, and to time infinity (AUC168h, AUClast, AUCinf), were markedly decreased for both total erdafitinib (56%-62%) and free erdafitinib (48%-55%). The safety profile of erdafitinib was consistent with previous clinical studies in healthy participants, with no new safety concerns when administered with or without carbamazepine. Co-administration with carbamazepine may reduce the activity of erdafitinib due to reduced exposure. Concomitant use of strong CYP3A4 inducers with erdafitinib should be avoided.

Increased APJ expression influences anoikis resistance and cell adhesion.

ML221 dose-response curves in OvCa cell lines.

APJ specifically increases proliferation in OvCa cells.

Various pro-metastatic pathways are upregulated downstream of APJ in OvCa cells.

Introduction Cancer immunotherapies have limited efficacy in prostate cancer due to the immunosuppressive prostate microenvironment. Prostate specific membrane antigen (PSMA) expression is prevalent in prostate cancer, preserved during malignant transformation, and increases in response to anti-androgen therapies, making it a commonly targeted tumor associated antigen for prostate cancer. JNJ-63898081 (JNJ-081) is a bispecific antibody targeting PSMA-expressing tumor cells and CD3-expressing T cells, aiming to overcome immunosuppression and promoting antitumor activity. Patients and Methods We conducted a phase 1 dose escalation study of JNJ-081 in patients with metastatic castration-resistance prostate cancer (mCRPC). Eligible patients included those receiving ≥1 prior line treatment with either novel androgen receptor targeted therapy or taxane for mCRPC. Safety, pharmacokinetics, and pharmacodynamics of JNJ-081, and preliminary antitumor response to treatment were evaluated. JNJ-081 was administered initially by intravenous (IV) then by subcutaneous (SC) route. Results Thirty-nine patients in 10 dosing cohorts received JNJ-081 ranging from 0.3 µg/kg to 3.0 µg/kg IV and 3.0 µg/kg to 60 µg/kg SC (with step-up priming used at higher SC doses). All 39 patients experienced ≥1 treatment-emergent AE, and no treatment-related deaths were reported. Dose-limiting toxicities were observed in 4 patients. Cytokine release syndrome (CRS) was observed at higher doses with JNJ-081 IV or SC; however, CRS and infusion-related reaction (IRR) were reduced with SC dosing and step-up priming at higher doses. Treatment doses >30 µg/kg SC led to transient PSA decreases. No radiographic responses were observed. Anti-drug antibody responses were observed in 19 patients receiving JNJ-081 IV or SC. Conclusion JNJ-081 dosing led to transient declines in PSA in patients with mCRPC. CRS and IRR could be partially mitigated by SC dosing, step-up priming, and a combination of both strategies. T cell redirection for prostate cancer is feasible and PSMA is a potential therapeutic target for T cell redirection in prostate cancer.

Antibody dilutions used for Western blot and Immunohistochemical analyses.

Increased APJ expression in vivo has no significant effect on tumor volume or mouse weights in OvCa mouse models.

279 Background: PSMA expression is increased in response to anti-androgen therapies and is a promising therapeutic target for the treatment of prostate cancer (PCa). JNJ-081 is a bispecific antibody with one arm binding PSMA on cancer cells and the other binding CD3 on T-cells to promote anti-tumor activity. Methods: This Phase 1 Dose Escalation Study evaluated JNJ-081 in mCRPC participants (pts) who progressed after novel androgen targeting therapy (eg, abiraterone, enzalutamide or apalutamide). Prior chemotherapy was permitted. JNJ-081 was administered initially by intravenous (IV) then by subcutaneous (SC) route. Dose escalation followed a continuous reassessment method based on a Bayesian regression model. The primary endpoint to determine the recommended phase 2 dose (RP2D) was based on safety. Pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, and preliminary anti-tumor activity were also evaluated. Cytokine release syndrome (CRS) was graded by CTCAE V5. Results: As of 10 May 2021, 39 pts were dosed in 10 cohorts ranging from 0.1 µg/kg to 3 µg/kg IV and from 3 µg/kg to 60 µg/kg SC. Premedications included high dose corticosteroids. Step-up priming was implemented at higher SC doses. Most common treatment-emergent AEs were CRS (65%), fatigue (49%) and nausea (43%). 2 pts developed DLTs of Grade (G) 3 or G4 transaminases increased, 1 each at 30 µg/kg SC and priming with 10 µg/kg SC then 55 µg/kg SC, respectively. Both DLTs were in conjunction with or followed an episode of G2 CRS. SC route as well as step-up priming helped mitigate CRS and infusion-related reaction (IRR) during escalation to higher doses: at 3 µg/kg IV, 4 of 5 pts had G2 CRS or IRR; at 30 µg/kg SC, 3 of 4 pts had G2 CRS; priming with 10 µg/kg then 55 µg/kg SC, 4 of 5 pts had G2 CRS. Injection site reactions (G1 or G2) occurred in 24 of 26 pts treated via SC JNJ-081. No treatment related death was reported. Transient PSA decreases were observed at treatment doses greater than 30 µg/kg SC. Two subjects treated with 55 µg/kg had PSA decreases > 50%. No radiographic responses were observed. PK of JNJ-081 was linear over the dose range of 3-60 µg/kg following SC administration. SC bioavailability was approximately 25%. Anti-drug antibodies (ADA) were detected in 2 of 12 subjects treated by IV administration and 14 of 23 pts treated by SC administration. ADA resulted in loss of exposure in some SC pts. Intrapatient dose escalation in 3 pts did not overcome the reduced exposure after ADA seropositivity. Conclusions: JNJ-081 demonstrated transient decreases in PSA in mCRPC patients. Grade 2 CRS was observed at higher doses and was partially mitigated by SC and step-up dosing. ADA resulting in decreased exposure occurred in the majority of pts treated SC. PSMA remains a potential therapeutic target for T-cell redirection for the treatment of PCa. Clinical trial information: NCT03926013.

Background: The near impermeability of the blood-brain barrier (BBB) and the unique neuroimmune environment of the CNS prevents the effective use of antibodies in neurological diseases. Delivery of bio-therapeutics to the brain can be enabled through receptor-mediated transcytosis via proteins such as the transferrin receptor, although limitations such as the ability to use Fc-mediated effector function to clear pathogenic targets can introduce safety liabilities. Hence, novel delivery approaches with alternative clearance mechanisms are warranted. Methods: Binders that optimized transport across the BBB, known as transcytosis-enabling modules (TEMs), were identified using a combination of antibody discovery techniques and pharmacokinetic analyses. Functional activity of TEMs were subsequently evaluated by imaging for the ability of myeloid cells to phagocytose target proteins and cells. Findings: We demonstrated significantly enhanced brain exposure of therapeutic antibodies using optimal transferrin receptor or CD98 TEMs. We found that these modules also mediated efficient clearance of tau aggregates and HER2+ tumor cells via a non-classical phagocytosis mechanism through direct engagement of myeloid cells. This mode of clearance potentially avoids the known drawbacks of Fc gamma R-mediated antibody mechanisms in the brain such as the neurotoxic release of proinflammatory cytokines and immune cell exhaustion. Conclusions: Our study reports a new brain delivery platform that harnesses receptor-mediated transcytosis to maximize brain uptake and uses a non-classical phagocytosis mechanism to efficiently clear pathologic proteins and cells. We believe these findings will transform therapeutic approaches to treat CNS diseases.

Background and PurposeAntigen‐binding fragment (Fab) reversal agents were developed to reverse, in bleeding emergency, the long‐acting anticoagulant effect of JNJ‐64179375 (JNJ‐9375), a monoclonal antibody that binds exosite‐1 on thrombin.Experimental ApproachThe pharmacokinetic and pharmacodynamic (PK/PD) activities of three reversal agents of varying in vitro binding affinities to JNJ‐9375 were characterised in cynomolgus monkeys. The time course of JNJ‐9375 anticoagulant activity and reversal effects of each agent were evaluated. A mechanism‐based PK/PD model, which integrated free serum concentrations of reversal agent, total and free serum concentrations of JNJ‐9375, and thrombin time, was developed to quantitatively relate JNJ‐9375 neutralisation to reversal of induced thrombin time prolongation. Model‐based allometric scale‐up of the lead reversal agent and the PK/PD relationship of JNJ‐9375 in healthy volunteers were utilised to predict clinical dosing regimens.Key ResultsLowering of free JNJ‐9375 by the reversal agents corresponded with reversal of thrombin time prolongation. Total JNJ‐9375 displayed typical mAb clearance at 2.75 ml·day−1·kg−1, whereas reversal agents cleared faster between 1400 and 2400 ml·day−1·kg−1. The model‐estimated in vivo KD values for JNJ‐9375 reversal agents were 9 nM (ICHB‐256), 0.4 nM (ICHB‐281) and 13.7 pM (ICHB‐164), in rank‐ordered agreement of their KD values determined in vitro. The three reversal agents exhibited different neutralisation characteristics in vivo, governed primarily by their binding kinetics to JNJ‐9375. The model predicted a priori free JNJ‐9375 kinetics after dosing ICHB‐164 (JNJ‐67842125) and JNJ‐9375 under a different regimen.Conclusion and ImplicationsThe results enabled selection of JNJ‐67842125 as the reversal agent for JNJ‐9375.

VEGF-mediated tumor angiogenesis is a validated clinical target in many cancers, but modest efficacy and rapid development of resistance are major challenges of VEGF-targeted therapies. To establish a molecular signature of this resistance in ovarian cancer, we developed preclinical tumor models of adaptive resistance to chronic anti-VEGF treatment. We performed RNA-seq analysis and reverse-phase protein array to compare changes in gene and protein expressions in stroma and cancer cells from resistant and responsive tumors. We identified a unique set of stromal-specific genes that were strongly correlated with resistance phenotypes against two different anti-VEGF treatments, and selected the apelin/APJ signaling pathway for further in vitro validation. Using various functional assays, we showed that activation of apelin/APJ signaling reduces the efficacy of a VEGF inhibitor in endothelial cells. In patients with ovarian cancer treated with bevacizumab, increased expression of apelin was associated with significantly decreased disease-free survival. These findings link signature gene expressions with anti-VEGF response, and may thus provide novel targetable mechanisms of clinical resistance to anti-VEGF therapies.

T cell-redirecting bispecific antibodies (bsAbs) are highly potent tumor-killing molecules. Following bsAb mediated engagement with target cells, T cells get activated and kill target cells while inducing cytokine release, which at higher levels may lead to life-threatening cytokine release syndrome (CRS). Clinical evidence suggests that CRS can be mitigated by implementing a stepwise dosing strategy. Here, we developed a mechanism-based minimal physiologically-based pharmacokinetic/pharmacodynamic (mPBPK/PD) model using reported preclinical and clinical data from blinatumomab. The mPBPK/PD model reasonably captured blinatumomab PK and B cell depletion profiles in blood and in various tissue sites of action (i.e., red marrow perivascular niche, spleen, and lymph nodes) in patients with non-Hodgkin's lymphoma (NHL) and acute lymphoblastic leukemia (ALL). Using interleukin 6 (IL-6) as an example, our model quantitatively characterized the mitigation of cytokine release by a blinatumomab 5-15-60 mu g/m(2)/day stepwise dosing regimen comparing to a 60 mu g/m(2)/day flat dose in NHL patients. Furthermore, by only modifying the system parameters specific for ALL patients, the mPBPK/PD model successfully predicted the mitigation of IL-6 release by a blinatumomab 5-15 mu g/m(2)/day stepwise dosing regimen comparing to a 15 mu g/m(2)/day flat dose. Our work provided a case example to show how mPBPK/PD model can be used to support the discovery and clinical development of T cell-redirecting bsAbs.

High mortality rates in ovarian cancer are due to late-stage diagnosis when extensive metastases are present, coupled with the eventual development of resistance to standard chemotherapy. There is, thus, an urgent need to identify targetable pathways to curtail this deadly disease. In this study, we show that the apelin receptor, APJ, is a viable target that promotes tumor progression of high-grade serous ovarian cancer (HGSOC). APJ is specifically overexpressed in tumor tissue, and is elevated in metastatic tissues compared with primary tumors. Importantly, increased APJ expression significantly correlates with decreased median overall survival (OS) by 14.7 months in patients with HGSOC. Using various ovarian cancer model systems, we demonstrate that APJ expression in cancer cells is both necessary and sufficient to increase prometastatic phenotypes in vitro, including proliferation, cell adhesion to various molecules of the extracellular matrix (ECM), anoikis resistance, migration, and invasion; and these phenotypes are efficiently inhibited by theAPJ inhibitor, ML221. Overexpression of APJ also increases metastasis of ovarian cancer cells in vivo. Mechanistically, the prometastatic STAT3 pathway is activated downstream of APJ, and in addition to the ERK and AKT pathways, contributes to its aggressive phenotypes. Our findings suggest that the APJ pathway is a novel and viable target, with potential to curb ovarian cancer progression and metastasis. Implications: The APJ pathway is a viable target in HGSOC.