XmAb541 / Xencor - LARVOL DELTA

Phase 1, Safety and Tolerability Study of XmAb541 and XmAb808 in Advanced Solid Tumors (clinicaltrials.gov) - P1 | N=90 | Recruiting | Sponsor: Xencor, Inc. | Not yet recruiting ➔ Recruiting

Enrollment open • Oncology • Ovarian Cancer • Solid Tumor • CLDN6

XmAb541 Clinical Data (Businesswire) - "Emerging data from XmAb541 monotherapy indicate clinical activity to date at the putative RP3D in heavily-pretreated patients, with an approximate 14% overall response rate (ORR) in patients with ovarian cancer and an approximate 28% ORR in patients with germ cell tumors, which supports further evaluation in combination with XmAb808 to provide tumor-targeted CD28 agonism and additional T-cell stimulation....Based on monotherapy data, in July 2026 the U.S. FDA granted Fast Track designation to XmAb541 for the treatment of patients with germ cell tumors who have relapsed following two or more lines of platinum therapy or were refractory to prior platinum therapy."

Fast track • P1 data • Germ Cell Tumors • Ovarian Cancer

XmAb541 (CLDN6 x CD3) in combination with XmAb808 (B7-H3 x CD28), in Phase 1 clinical development for T-cell engagement of Claudin-6 expressing tumors, including high-grade serous ovarian cancer (Businesswire) - "XmAb541 development in the ongoing Phase 1 dose-escalation study in combination with XmAb808 has been prioritized. XmAb541 monotherapy expansion cohorts at the putative RP3D (60 mg dosed every 3 weeks) in high-grade serous ovarian carcinoma (TPS≥50) and germ cell tumors are expected to complete enrollment by year end, with the data supporting combination development with XmAb808. The Phase 1 dose-escalation study of XmAb541 and XmAb808 is ongoing and expected to reach the combination’s target dose range in 2027."

Trial status • Germ Cell Tumors • Ovarian Cancer

Phase 1, Safety and Tolerability Study of XmAb541 and XmAb808 in Advanced Solid Tumors (clinicaltrials.gov) - P1 | N=90 | Not yet recruiting | Sponsor: Xencor, Inc.

New P1 trial • Oncology • Ovarian Cancer • Solid Tumor • CLDN6

Wholly Owned Pipeline Overview:…XmAb541 (CLDN6 x CD3) (Businesswire) - "(i) Xencor plans to present Phase 1 dose-escalation data to define a recommended Phase 3 target dose in 2H26 and evaluate plans for a pivotal study of XmAb541 during 2027; (ii) Additionally, Xencor is initiating a new clinical study to evaluate the combination of XmAb541 and XmAb808 (B7H3 x CD28) for patients with CLDN6+ high-grade serous ovarian cancer."

New trial • P1 data • Germ Cell Tumors • Gynecologic Cancers • High Grade Serous Ovarian Cancer

XmAb808, a B7H3-targeted CD28 bispecific antibody, costimulates T cells enhancing the anti-tumor activity of clinically active CD3 T cell engagers (AACR 2026) - "Notably, XmAb808 synergistically enhanced the activity of XmAb541 (CLDN6xCD3) and an analog of xaluritamig (STEAP1xCD3), two programs with clinically observed anti-tumor activity. Moreover, in a T cell restimulation assay, XmAb808 was able to overcome apparent T cell exhaustion promoted by xaluritamig, strongly recovering xaluritamig's reduced anti-tumor activity weeks into the assay. The addition of targeted costimulation translated to superior T cell-mediated cytotoxicity in vitro and markedly improved anti-tumor responses in humanized xenograft models, highlighting XmAb808's potential to synergize with TCE-based immunotherapies."

Bispecific • Clinical • IO biomarker • Oncology • Ovarian Cancer • Prostate Cancer • Solid Tumor • BCL2L1 • CD276 • CLDN6 • STEAP1

XmAb541-01: Phase 1, Safety and Tolerability Study of XmAb541 in Advanced Solid Tumors (clinicaltrials.gov) - P1 | N=282 | Recruiting | Sponsor: Xencor, Inc. | N=212 ➔ 282

Enrollment change • First-in-human • Endometrial Cancer • Germ Cell Tumors • Oncology • Ovarian Cancer • Solid Tumor • Testicular Cancer • CLDN6

XmAb541-01: A Study Testing the Investigational Drug XmAb541 in people with Advanced Cancer (clinicaltrialsregister.eu) - P1 | N=70 | Not yet recruiting | Sponsor: Xencor Inc.

New P1 trial • Oncology • Solid Tumor

XmAb541 (CLDN6 x CD3), a novel, first-in-class, tumor-targeted T-cell engaging XmAb 2+1 bispecific antibody in development for patients with advanced gynecologic and germ cell tumors. (FinancialContent) - "We plan to: Present new clinical data to support a recommended Phase 3 dose in 2H26; Initiate a pivotal study of XmAb541 during 2027."

New trial • P1 data • Endometrial Cancer • Germ Cell Tumors • Ovarian Cancer • Testicular Cancer

XmAb541 (CLDN6 x CD3), a novel, first-in-class, tumor-targeted T-cell engaging XmAb 2+1 bispecific antibody in development for patients with advanced gynecologic and germ cell tumors (Businesswire) - "Xencor plans to select a recommended Phase 3 dose during 2026 to support initiation of a pivotal study during 2027. In October 2025, Xencor presented early efficacy data from a cohort in the ongoing Phase 1 dose-escalation study of XmAb541, ahead of previously guided timelines to begin characterizing target dose range cohorts by year-end 2025. As of the data cut-off, nine patients received XmAb541 in the most recently completed escalation cohort. Confirmed partial responses per RECIST v1.1 were observed in three patients: one patient with ovarian cancer and two patients with germ cell tumors."

New P3 trial • P1 data • Trial status • Germ Cell Tumors • Ovarian Cancer

XmAb541-01: Phase 1, Safety and Tolerability Study of XmAb541 in Advanced Solid Tumors (clinicaltrials.gov) - P1 | N=212 | Recruiting | Sponsor: Xencor, Inc. | Completed ➔ Recruiting | N=60 ➔ 212 | Trial completion date: May 2025 ➔ Dec 2028 | Trial primary completion date: May 2025 ➔ Dec 2027

Enrollment change • Enrollment open • Trial completion date • Trial primary completion date • Endometrial Cancer • Germ Cell Tumors • Oncology • Ovarian Cancer • Solid Tumor • Testicular Cancer

XmAb541-01: Phase 1, Safety and Tolerability Study of XmAb541 in Advanced Solid Tumors (clinicaltrials.gov) - P1 | N=60 | Completed | Sponsor: Xencor, Inc. | Recruiting ➔ Completed | N=212 ➔ 60 | Trial completion date: Dec 2028 ➔ May 2025 | Trial primary completion date: Dec 2027 ➔ May 2025

Enrollment change • Trial completion • Trial completion date • Trial primary completion date • Endometrial Cancer • Germ Cell Tumors • Oncology • Ovarian Cancer • Solid Tumor • Testicular Cancer

Xencor Reports Second Quarter 2025 Financial Results (Businesswire) - "Clinical Program Updates: Oncology:...(i) Xencor is conducting a Phase 1 study to evaluate XmAb819 in patients with advanced ccRCC and plans to present initial dose-escalation data at a medical conference during the fourth quarter of 2025....; (ii) A Phase 1 dose-escalation study to evaluate XmAb541 in patients with ovarian cancer, germ cell tumors, and other CLDN6-expressing tumor types is ongoing, with characterization of target dose levels anticipated to begin during 2025."

P1 data • Trial status • Clear Cell Renal Cell Carcinoma • Germ Cell Tumors • Ovarian Cancer

A Phase 1, First-in-Human, Dose Escalation and Expansion Study to Evaluate the Safety and Tolerability of XmAb541 (Claudin-6 x CD3) T-cell engaging Bispecific Antibody in Advanced Solid Tumors (SGO 2025) - No abstract available

Clinical • Metastases • P1 data • Oncology • Solid Tumor • CLDN6

Clinical Program Updates and 2025 Priorities (Businesswire) - "Xencor is conducting a Phase 1 study to evaluate XmAb819 in patients with advanced ccRCC and plans to present initial data at a medical conference during the second half of 2025...The 2+1 multivalent format enables greater selectivity for targeting the tumor-associated antigen CLDN6 over similar Claudin family members, and new preclinical data demonstrating this selectivity were presented in January 2025. A Phase 1 dose-escalation study to evaluate XmAb541 in patients with ovarian cancer and other CLDN6-expressing tumor types is ongoing, with characterization of target dose levels anticipated to begin during 2025."

P1 data • Preclinical • Trial status • Clear Cell Renal Cell Carcinoma • Solid Tumor

A phase 1, first-in-human, dose escalation and expansion study to evaluate the safety and tolerability of XmAb541 (claudin-6 x CD3) T-cell engaging bispecific antibody in subjects with germ cell tumors and other advanced solid tumors. (ASCO-GU 2025) - P1 | "(AACR 2021, Abstract No. 1860)"

Clinical • Metastases • P1 data • Genito-urinary Cancer • Germ Cell Tumors • Oncology • Solid Tumor • CLDN6

Xencor Reports First Quarter 2024 Financial Results (Businesswire) - "First Patient Dosed in Phase 1 Study of XmAb541 (CLDN6 x CD3): XmAb541 is a bispecific antibody being developed for patients with CLDN6-positive tumors including advanced ovarian cancer....The first patient was recently dosed in a Phase 1 dose-escalation study."

Trial status • Endometrial Cancer • Germ Cell Tumors • Ovarian Cancer • Testicular Cancer

XmAb541-01: Phase 1, Safety and Tolerability Study of XmAb®541 in Advanced Solid Tumors (clinicaltrials.gov) - P1 | N=212 | Recruiting | Sponsor: Xencor, Inc. | Not yet recruiting ➔ Recruiting

Enrollment open • Metastases • Endometrial Cancer • Germ Cell Tumors • Oncology • Ovarian Cancer • Solid Tumor • Testicular Cancer

Xencor Reports Fourth Quarter and Full Year 2023 Financial Results (Businesswire) - "XmAb541 (CLDN6 x CD3):...During the first half of 2024, Xencor plans to dose the first patient in a Phase 1 dose-escalation study....Xencor has been conducting Phase 1 studies evaluating...XmAb662 (IL12-Fc in solid tumors). In the first half of 2024, Xencor plans to conclude studies of...XmAb662, complete internal data packages, and pause further development of both programs until after assessments of future data from competitor programs in this class and safety and biomarker data from Xencor’s studies."

P1 data • Pipeline update • Trial status • Solid Tumor

Phase 1, Safety and Tolerability Study of XmAb®541 in Advanced Solid Tumors (clinicaltrials.gov) - P1 | N=212 | Not yet recruiting | Sponsor: Xencor, Inc.

Metastases • New P1 trial • Endometrial Cancer • Germ Cell Tumors • Oncology • Ovarian Cancer • Solid Tumor • Testicular Cancer

Xencor Reports Third Quarter 2023 Financial Results (Businesswire) - "Pipeline Updates: (i) Efbalropendekin alfa (XmAb306, IL15/IL15Rα-Fc Cytokine): Xencor exercised its right under the Genentech agreement to convert its co-development and sharing of profits and losses on efbalropendekin alfa into a milestone and royalty arrangement without cost-sharing. The Company expects to finalize contract changes before year end; (ii) XmAb541 (CLDN6 x CD3):...Xencor plans to submit an investigational new drug (IND) application by year end."

IND • Licensing / partnership • Oncology

Xencor Reports First Quarter 2023 Financial Results (Businesswire) - "...'Two new programs are planned to advance into clinical development this year, XmAb662, our engineered IL12-Fc cytokine, on track to start a Phase 1 study mid-year, and XmAb541, our CLDN6 x CD3 bispecific antibody for ovarian cancer, for which we anticipate submitting the IND by year end'."

IND • New P1 trial • Gynecologic Cancers • Oncology • Ovarian Cancer • Solid Tumor

Xencor Highlights 2023 Corporate Priorities and Provides Portfolio Updates (Businesswire) - "XmAb662: Xencor plans to...Initiate a Phase 1 study in patients with advanced solid tumors in mid-2023; XmAb541: Xencor plans to...Submit an investigational new drug application (IND) in 2023."

IND • New P1 trial • Oncology • Solid Tumor