ARC-20 Study Reveals Promising Results for Casdatifan and Cabozantinib in Metastatic Kidney Cancer

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Arcus Biosciences Reports Promising Early Data for Cancer Treatment Combo, Shares Surge

HAYWARD, Calif. – Arcus Biosciences (RCUS) is making waves in the biotech world today after unveiling encouraging initial results for its casdatifan-cabozantinib combo therapy in a Phase 1/1b study for clear cell renal cell carcinoma (ccRCC). The company announced the findings at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting, sending a strong signal to investors.

The data, presented by Dr. Toni K. Choueiri of the Dana-Farber Cancer Institute, showcased a confirmed overall response rate (ORR) of 46% among patients who had at least 12 weeks of follow-up. This early success is particularly notable given the challenging landscape of ccRCC treatment.

“I was very encouraged to see that nearly half of patients had a confirmed response to the casdatifan plus cabozantinib combination despite short follow-up,” commented Dr. Choueiri, a key investigator in the ARC-20 study. “Casdatifan plus cabozantinib was well tolerated, and the safety profile was consistent with that of either agent alone, supporting their potential as a combination therapy.”

The study involved patients with ccRCC who had progressed on prior immunotherapy. Of the 42 patients evaluated for safety, 79% had intermediate or poor risk factors based on the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) criteria. 24 patients were evaluable for efficacy. The results have fueled optimism and prompted plans for further, larger trials.

Arcus CEO Terry Rosen, Ph.D. highlighted the significance of the findings, stating, “The initial data for casdatifan plus cabozantinib in the ARC-20 study have already exceeded the historic benchmarks for either agent alone, as well as that of another HIF-2a inhibitor plus cabozantinib in the same second-line setting.”

The company has already initiated several development programs to maximize the opportunity this combo therapy offers:

* The upcoming Phase 3 study, PEAK-1, evaluating casdatifan plus cabozantinib versus cabozantinib monotherapy, in patients whose ccRCC has advanced despite prior anti-PD-1/PD-L1 therapy.
* The eVOLVE-RCC02 Phase 1b/3 trial will evaluate casdatifan with volrustomig, an investigational anti-PD-1/CTLA-4 bispecific antibody, as a first-line option.
* ARC-20 including three cohorts evaluating casdatifan in earlier-line settings, including a combination with zimberelimab in first-line ccRCC, casdatifan monotherapy in favorable risk ccRCC, and casdatifan monotherapy in immunotherapy-experienced, TKI-naive settings .

**The Key Data Points:**

Here’s a quick rundown of the core findings from the ARC-20 study:

| | casdatifan 100mg QD + cabozantinib 60mg QD |
| :——————————— | :——————————————- |
| Median Follow-Up | 5.3 months |
| Confirmed ORR (cORR) per RECIST v1.1 | 46% (11) |
| [95% CI] | [26,67] |
| Complete Response | 4% (1) |
| Partial Response | 42% (10) |
| Stable Disease | 50% (12) |
| Progressive Disease | 4% (1) |

| | | |
| :————————————————————– | :————————————– | ——- |
| | casdatifan | cabozantinib |
| Patients with any Treatment-Related Grade ≥3 AE | | |
| Anemia | 24% (10) | 14% (6) |
| Hyponatremia | 0 | 7% (3) |
| Hypoxia | 7% (3) | 0 |
| Hypertension | 0 | 5% (2) |
| Neutrophil count decrease | 2% (1) | 5% (2) |

The company also noted that the combination therapy exhibited a manageable safety profile, with no overlapping toxicity concerns.

**The Bigger Picture**

Casdatifan is a small-molecule inhibitor of HIF-2a, a protein implicated in the growth of tumors in ccRCC. Clear cell renal cell carcinoma is the most common type of kidney cancer in adults.

“These data serve as the proof of concept for PEAK-1, which will be initiated in the coming weeks and is designed to generate evidence to change the standard of care for people who have progressed on prior immunotherapy treatment,” explained Arcus CEO Dr. Rosen.

Arcus has indicated that, Investors, analysts, and the public can learn more during a conference call on Monday, June 2, 2025, at 5:00 AM PT / 7:00 AM CT.