Avacta reports new Phase 1a/1b data showing faridoxorubicin delivers durable antitumor activity in salivary gland cancer despite low FAP expression, reinforcing the broad potential of its tumor‑activated pre|CISION® platform.
Written By: Kalyani Boharapi, M.Pharm (QA)
Reviewed By: Pharmacally Editorial Team
Avacta Therapeutics has reported new clinical and translational data from its ongoing Phase 1a/1b study (NCT04969835) of faridoxorubicin (AVA6000), showing sustained antitumor activity in patients with salivary gland cancer (SGC) despite minimal fibroblast activation protein (FAP) expression. The updated findings also indicate that FAP expression persists during treatment, supporting the mechanism of the company’s tumor-activated pre|CISION® platform.
The results provide additional evidence that faridoxorubicin can produce clinically meaningful responses even in tumors with low FAP levels, expanding the potential applicability of the platform beyond cancers with high FAP expression. Additional clinical updates are expected during the third quarter of 2026.
About Faridoxorubicin and the pre|CISION® Platform
Faridoxorubicin is a tumor-activated form of doxorubicin developed using Avacta’s pre|CISION® technology. The platform is engineered to activate chemotherapy primarily within the tumor microenvironment through cleavage by FAP, an enzyme commonly found in cancer-associated fibroblasts (CAFs). This targeted activation aims to increase tumor drug exposure while limiting systemic toxicity associated with conventional chemotherapy.
The latest findings also support the proposed “bystander effect,” in which activated chemotherapy diffuses into nearby tumor cells even when FAP is expressed mainly by surrounding stromal cells rather than the tumor itself.
Phase 1a/1b Study Shows Durable Activity in Salivary Gland Cancer
The salivary gland cancer cohort included 32 patients, representing the population selected for the planned pivotal study after excluding rare SGC subtypes with distinct disease behavior.
Among these patients:
- Four achieved confirmed partial responses.
- Eight experienced confirmed minor responses, defined as a 10% to 29% reduction in the sum of tumor diameters.
- Median progression-free survival (PFS) has not yet been reached, as patient follow-up continues and progression events remain under evaluation.
- Overall survival data are also still maturing.
Tumor responses were also observed in patients with soft tissue sarcoma (STS), while enrollment continues in the triple-negative breast cancer (TNBC) cohort. Data from the TNBC cohort will be reported after additional follow-up.
Translational Studies Support Activity at Low FAP Expression
Biopsy samples from 26 patients with salivary gland cancer underwent FAP immunohistochemistry and tri-color immunofluorescence analysis. Two independent statistical analyses found no association between the degree of FAP expression and tumor response, indicating that faridoxorubicin remained active even in tumors expressing very low levels of the target enzyme.
Investigators also evaluated FAP expression using [^18F]FAPI-74 PET imaging in a dedicated translational substudy. Preliminary findings from two responding patients showed that FAP expression persisted despite substantial tumor shrinkage. Because FAP functions as an extracellular enzyme, it remains available to activate the prodrug without requiring cellular internalization, providing a biological explanation for the durable responses observed.
Clinical Significance
Chief Executive Officer Christina Coughlin said the updated results strengthen confidence in the pre|CISION® platform by demonstrating meaningful clinical activity across tumors with varying FAP expression. She also noted that the immature median progression-free survival data in salivary gland cancer suggest faridoxorubicin may continue to provide durable disease control, consistent with observations from the earlier Phase 1a study.
Clinical Path Forward
The latest clinical and translational findings further support the broad applicability of Avacta’s pre|CISION® technology across multiple solid tumors. As follow-up continues, the company expects to report additional data from the salivary gland cancer and triple-negative breast cancer cohorts during Q3 2026, while advancing preparations for the planned pivotal study in salivary gland cancer.
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About the Writer
Kalyani Boharapi (LinkedIn) is a pharmacy professional and healthcare writer currently pursuing an M.Pharm in Regulatory Affairs at Dr. D. Y. Patil College of Pharmacy, with interests in pharmaceutical regulations, drug development, and healthcare innovation. She has academic exposure to dossier preparation, scientific writing, and regulatory documentation. Kalyani has also completed certification courses in Generative AI, AI in Pharma, and Bioinformatics, and actively participates in pharmaceutical conferences to stay updated with emerging trends and advancements in the healthcare and pharmaceutical industry.