On June 13, 2025 Arvinas, Inc. (Nasdaq: ARVN), a clinical-stage biotechnology company working to develop a new class of drugs based on targeted protein degradation, reported data from preclinical studies of ARV-393, the company’s investigational PROteolysis TArgeting Chimera (PROTAC) B-cell lymphoma 6 protein (BCL6) degrader (Press release, Arvinas, JUN 13, 2025, View Source [SID1234653873]). BCL6 is a transcriptional repressor protein and a known driver of B-cell lymphomas. ARV-393 demonstrated significant single-agent activity in a patient derived xenograft (PDX) model of nodal T-follicular helper cell lymphoma, angioimmunoblastic-type (nTFHL-AI also known as AITL) and PDX models of transformed follicular lymphoma (tFL). In combination with oral small molecule inhibitors (SMIs), ARV-393 demonstrated enhanced antitumor activity, including tumor regressions, in cell line-derived xenograft (CDX) models of high-grade B-cell lymphoma (HGBCL) and aggressive diffuse large B-cell lymphoma (DLBCL). The results from these preclinical studies were shared at the European Hematology Association (EHA) (Free EHA Whitepaper) 2025 Congress in Milan, Italy.

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Key findings from the preclinical studies included:

Single-agent ARV-393 significantly reduced tumor burden in peripheral blood, bone marrow and spleen in a systemic PDX model of nTFHL-AI derived from a patient who relapsed post chemotherapy. This is potentially the first preclinical evidence of anti-tumor activity with an efficacious BCL6-targeted small-molecule degrader in a human nTFHL-AI model.
ARV-393 monotherapy treatment resulted in robust (≥95%) tumor growth inhibition (TGI) in two PDX models of tFL.
ARV-393 in combination with 5 classes of SMIs targeting potentially cooperative oncogenic drivers (tazemetostat, palbociclib, everolimus, acalabrutinib, or venetoclax) demonstrated increased TGI in CDX models of HGBCL and aggressive DLBCL compared with the respective monotherapy treatments. Tumor regressions were observed when ARV-393 was combined with tazemetostat, palbociclib, acalabrutinib, or venetoclax.
RNA sequencing studies carried out to further characterize downstream mechanism of action suggested that ARV-393 inhibits tumor cell cycle progression and promotes differentiation, driving antitumor activity and broad combinability in preclinical models.
"We are encouraged by the marked single-agent activity of ARV-393 in PDX models of AITL and transformed follicular lymphoma and by the enhanced antitumor activity of ARV-393 in combination with five classes of small molecule inhibitors in models of aggressive DLBCL," said Noah Berkowitz, M.D., Ph.D., Chief Medical Officer at Arvinas. "We believe these preclinical data potentially suggest the broad utility of ARV-393 across non-Hodgkin lymphoma subtypes with unmet need beyond DLBCL and provide a compelling rationale for considering combination strategies including chemotherapy-free approaches as we work to bring forward new therapeutic options for adult patients with lymphoma."

A Phase 1 study of ARV-393 is enrolling adult patients with relapsed/refractory non-Hodgkin lymphoma, including DLBCL and nTFHL-Al (AITL) (NCT06393738).

Additional detail on the ARV-393 data presentation at the EHA (Free EHA Whitepaper) 2025 Congress:

Poster Title: ARV-393, a PROteolysis TArgeting Chimera (PROTAC) BCL6 Degrader, is Efficacious in Preclinical Models of Diffuse Large B-Cell Lymphoma, Nodal T-Follicular Helper Cell Lymphoma, and Transformed Follicular Lymphoma

Abstract: PF1000
Session Title: Lymphoma biology & translational research 
Date: Thursday, June 13, 2025
Time: 6:30-7:30 pm CEST

About ARV-393
ARV-393 is an investigational orally bioavailable PROteolysis TArgeting Chimera (PROTAC) designed to degrade B-cell lymphoma 6 protein (BCL6), a transcriptional repressor and major driver of B-cell lymphomas. The BCL6 protein facilitates B cell tolerance of rapid proliferation and somatic gene recombination via repressing cell cycle checkpoints, terminal differentiation, apoptosis, and the DNA damage response. PROTAC-mediated degradation has the potential to address the traditional undruggable nature of BCL6. ARV-393 is currently being evaluated in a Phase 1 clinical trial in patients with relapsed/refractory non-Hodgkin lymphoma.