Salubris Biotherapeutics Presents Phase 1/2 Dose Escalation and Expansion Cohort Data for JK06, 5T4-Targeted Antibody Drug Conjugate, at the American Association for Cancer Research Annual Meeting

10 confirmed partial responses (PRs) among 38 response-evaluable non-small cell lung cancer (NSCLC) patients (ORR 26%), including three of seven squamous cell NSCLC patients (ORR 43%)

Five confirmed PRs among 19 response-evaluable breast cancer patients (ORR 26%), including four of nine hormone receptor-positive (HR+) breast cancer patients (ORR 44%)

JK06 continues to demonstrate a favorable safety profile with overall low frequency and manageable adverse events (AEs), and infrequent ≥ Grade 3 AEs

GAITHERSBURG, Md.--(BUSINESS WIRE)--Salubris Biotherapeutics, Inc. (SalubrisBio), a clinical-stage biotechnology company dedicated to discovering and developing novel complex biologic therapeutics, today announced expansion cohort data from the Phase 1/2 study of JK06, a 5T4-targeted antibody drug conjugate (ADC), in patients with unresectable locally advanced or metastatic cancer, including non-small cell lung cancer (NSCLC) and breast cancer, which is being presented at the American Association for Cancer Research (AACR) Annual Meeting 2026 on April 17-22, 2026 in San Diego, California.

“JK06 continues to demonstrate encouraging and durable efficacy among heavily pre-treated metastatic solid tumors. Partial responses have now been observed across four different cancers, including NSCLC and breast cancer, at multiple dose levels. These data are complemented by a consistently favorable safety profile, underscoring our belief that JK06 has the potential to be an important new first-in-class ADC that can address the unmet needs of patients with 5T4-expressing cancers,” said Sam Murphy, Chief Executive Officer of Salubris Biotherapeutics. “These results provide a robust foundation for further exploration of JK06 in NSCLC and breast cancer and will propel our efforts to interrogate the pan-tumor opportunity. We look forward to progressing this study into the next stages of expansion cohorts, including additional monotherapy cohorts and evaluation of JK06 in multiple combination therapy regimens.”

Expansion cohort data presented at AACR include 112 patients enrolled in Europe with advanced relapsed/refractory solid tumors who were treated with JK06 once every three weeks, including two randomized dose cohorts (3.7 mg/kg, 4.5 mg/kg) in NSCLC and breast cancer and a basket cohort consisting of multiple tumor types known to express 5T4. The data cutoff was March 29, 2026.

Key efficacy findings include:

• Among 38 response-evaluable NSCLC patients, 10 attained confirmed PRs (ORR 26%), including three out of seven response-evaluable squamous cell NSCLC patients (ORR 43%), and two of three response-evaluable Epidermal Growth Factor Receptor (EGFR) mutant patients.
• Five out of 19 response-evaluable breast cancer patients attained PRs (ORR 26%), including four out of nine hormone receptor-positive (HR+) breast cancer patients (ORR 44%).
• Among other tumor types, the first and only response-evaluable gastric cancer patient enrolled attained a partial response (PR, -55%), and one of four response-evaluable cervical cancer patients attained a partial response (PR, -49%).

Among 112 safety-evaluable patients enrolled in expansion cohorts, key safety findings include:

• Treatment with JK06 at doses ≤ 5.2 mg/kg was generally well-tolerated with predominantly low grade (Grades 1 and 2) treatment-related adverse events (TRAEs) and manageable toxicities.
• All JK06-related AEs of any grade are below 10% frequency overall except for asthenia (11% overall).
• Only three total Grade 3 events have been observed to date among the 112 patients (fatigue, gait disturbance, keratitis), and no Grade 4 or 5 events have been observed.

Of the total 153 patients enrolled across all dose levels in dose escalation and expansion, only seven patients have dose-reduced due to a TRAE resulting from JK06.

The Phase 1/2 open-label, dose-escalation and expansion study (NCT06667960) to assess the safety, pharmacokinetics, and preliminary efficacy of JK06 is ongoing.

Details of the AACR presentation are as follows:

Title: A Phase 1/2 Study of JK06, a 5T4-Targeted Antibody Drug Conjugate (ADC), In Patients with Unresectable Locally Advanced or Metastatic Cancer
Presenter: Omar Saavedra, M.D., Vall d’Hebron Institute of Oncology (VHIO), Barcelona, Spain
Abstract #: CT250
Session: Phase II Clinical Trials
Date/Time: April 21, 2026 | 2:00 – 5:00 PM PT

About JK06

JK06 is a first-in-class quadrivalent, biparatopic ADC that selectively targets 5T4 with a monomethyl auristatin E (MMAE) payload. 5T4 is an oncofetal protein that is overexpressed in a wide range of solid tumors, including non-small cell lung cancer (NSCLC), breast, gastric and genitourinary cancers, and is associated with more aggressive tumor progression and reduced survival. JK06 has demonstrated picomolar affinity for 5T4 and enhanced internalization resulting from the biparatopic design. Together with stable, site-specific payload conjugation, JK06 has demonstrated the potential for robust efficacy and a favorable safety profile.

About SalubrisBio

SalubrisBio is a clinical-stage biotechnology company dedicated to discovering and developing complex biologics for cardiovascular disease and oncology. The Company is currently progressing multiple innovative and rationally designed first-in-class therapeutics through clinical development programs, including JK07, the potential first disease-modifying biologic for heart failure, and JK06, a quadrivalent, biparatopic ADC targeting 5T4 for the treatment of cancer. SalubrisBio is headquartered in Gaithersburg, Maryland. For more information about SalubrisBio, visit us at www.salubrisbio.com and connect with us on LinkedIn.

For further information, please contact:
Argot Partners
212.600.1902 | SalubrisBio@argotpartners.com