Arcus & AVEO Target a Critical Gap in Advanced Kidney Cancer Care

HAYWARD, CA – July 22, 2026 – In the relentless and often incremental fight against cancer, genuine shifts in strategy can signal a new frontier of hope. Arcus Biosciences and AVEO Oncology recently announced such a move: a clinical collaboration to test a novel drug combination for patients with advanced kidney cancer. While corporate partnerships are common in biotech, this one stands out for its specific and urgent target: patients whose disease has progressed even after treatment with the latest class of breakthrough drugs. By combining Arcus’s investigational HIF-2α inhibitor, casdatifan, with AVEO’s approved VEGFR inhibitor, tivozanib, the companies are venturing into a challenging therapeutic space, aiming to create a tangible difference where options are rapidly dwindling.

The Evolving Battlefield of Kidney Cancer

Kidney cancer, specifically clear cell renal cell carcinoma (ccRCC), which is the most common form, presents a formidable challenge. While early detection leads to high survival rates, the prognosis dims considerably once the cancer metastasizes, with the five-year survival rate plummeting to just 19%. The treatment landscape has been revolutionized over the last decade, moving from broad-acting immunotherapies to highly specific targeted drugs.

Today's standard of care for advanced ccRCC often involves combining immune checkpoint inhibitors (ICIs) with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs). This one-two punch simultaneously unleashes the immune system against cancer cells and chokes off the tumor’s blood supply. More recently, a new class of drugs, HIF-2α inhibitors, has emerged as a major advancement. In over 90% of ccRCC cases, a genetic anomaly in the Von Hippel-Lindau (VHL) gene causes the rampant accumulation of a protein called hypoxia-inducible factor 2-alpha (HIF-2α), a master switch that drives tumor growth. Drugs like Merck’s belzutifan, the first FDA-approved HIF-2α inhibitor, directly block this driver, offering a powerful new weapon. But even with these breakthroughs, a critical question remains: what comes next when these treatments fail? This is the precise gap Arcus and AVEO aim to address.

A Strategic Combination to Overcome Resistance

The new clinical trial will evaluate casdatifan in combination with tivozanib in a cohort of patients whose cancer has progressed after receiving a prior HIF-2α inhibitor. The scientific rationale is rooted in tackling the complex mechanisms of treatment resistance from two different angles.

Casdatifan is Arcus's next-generation HIF-2α inhibitor, designed to provide what the company calls “deep and durable inhibition” of the HIF-2α pathway. While it shares a target with the first-generation inhibitor, Arcus believes its distinct pharmacological properties may offer an advantage, particularly in patients who have developed resistance. Early clinical data has reportedly shown high response rates, warranting this deeper investigation. Success in this trial could establish casdatifan not just as an alternative, but as an effective therapy for a population with no currently established standard of care.

Its partner in the trial, tivozanib (marketed as FOTIVDA®), is an established VEGFR TKI. It was approved by the FDA in 2021 for patients with advanced RCC who have failed two or more prior therapies. Its approval was based on the TIVO-3 study, where it demonstrated superior progression-free survival compared to another TKI in a heavily pretreated population. Critically, as noted by Arcus’s CEO, tivozanib has an “established, distinct safety profile.” For patients who have already endured multiple rounds of demanding treatments, a therapy's tolerability is just as important as its efficacy. Combining a potentially more potent HIF-2α inhibitor with a TKI known for its manageable side effects could prove to be a winning formula for extending life while preserving its quality.

Building a 'Backbone' Therapy, One Partnership at a Time

This collaboration is a clear window into Arcus Biosciences’ broader corporate strategy. The company is methodically working to position casdatifan as a “backbone therapy,” a foundational treatment that can be used across multiple stages of ccRCC. This is being executed through its ARC-20 platform study, a flexible trial design that allows for the evaluation of casdatifan in various combinations and settings—from first-line treatment to the second-line and beyond.

By pursuing a clinical supply agreement, Arcus can test its drug alongside an approved and effective agent from another company without the enormous cost and complexity of acquiring or co-developing it. This capital-efficient model accelerates data generation and allows the company to quickly test its hypotheses in well-defined patient populations. For AVEO Oncology, now an LG Chem company, the partnership provides an opportunity to expand the utility of tivozanib and maintain its relevance in an intensely competitive market, all while Arcus sponsors and conducts the trial.

“This collaboration with AVEO... will further our intent to establish casdatifan as a therapy that can benefit every patient across each line of therapy, and clarify the potential efficacy that casdatifan can bring in patients previously treated with a HIF-2α inhibitor-inclusive regimen,” stated Terry Rosen, Ph.D., chief executive officer of Arcus. This statement encapsulates a vision that extends far beyond a single clinical trial, revealing a deliberate, multi-pronged effort to build a franchise drug from the ground up.

The Human Impact: Hope for the Toughest Cases

Behind the corporate strategy and clinical science lies a story of tangible human need. For the thousands of Americans diagnosed with advanced kidney cancer each year, the cycle of treatment, response, and eventual progression is a grueling reality. The introduction of each new drug class brings a wave of optimism, but the fear of running out of options is ever-present. This new trial, set to begin enrolling later this year, directly confronts that fear.

By focusing on patients who have already seen their disease outsmart a first-generation HIF-2α inhibitor, the study is tackling one of the most difficult challenges in modern oncology. It represents a commitment to pushing the boundaries of what is possible and refusing to accept the current limits of care as final. While the path of clinical development is long and uncertain, this targeted effort provides a credible reason for optimism. For patients navigating the difficult terrain of advanced kidney cancer, this new avenue of research represents a tangible step forward in the ongoing search for more effective and durable treatments.