ArriVent BioPharma’s ARR-217 Shows 44.8% Response Rate in Colorectal Cancer Study

Key Points

• ARR-217 showed promising activity in heavily pretreated metastatic colorectal cancer, with a 44.8% objective response rate and 93.1% disease-control rate at the 6 mg/kg dose.
• The treatment had a generally manageable safety profile at 6 mg/kg, with mostly low-grade hematological and gastrointestinal adverse events, a 2% rate of severe diarrhea, and no treatment discontinuations due to adverse events at the data cutoff.
• ArriVent is continuing Phase Ib dose optimization, testing ARR-217 in combination with bevacizumab and chemotherapy, and targeting a potential Phase III trial launch by the end of 2027.

ArriVent BioPharma NASDAQ: AVBP presented Phase I data for ARR-217, its CDH17-targeting antibody-drug conjugate, or ADC, in heavily pretreated metastatic colorectal cancer patients during a virtual webinar following an ESMO late-breaking oral presentation.

The company said the early-stage study showed anti-tumor activity and a generally manageable safety profile, supporting continued dose optimization and plans for potential later-stage development. ARR-217 is being developed with Lepu Biopharma and uses an anti-CDH17 antibody linked to the topoisomerase 1 inhibitor exatecan.

Phase I colorectal cancer results

As of an Aug. 5, 2026 data cutoff, 123 patients had received ARR-217, including 113 with colorectal cancer. The colorectal cancer population had received a median of three prior lines of therapy, according to Preethi Shaker, ArriVent’s vice president of clinical development. More than half had liver metastases, nearly 60% had RAS mutations, and most had microsatellite-stable disease.

Among 75 treated patients with at least one post-baseline tumor assessment, the company reported the strongest activity at the 6 mg/kg dose. ARR-217 produced an objective response rate of 44.8% and a disease-control rate of 93.1% at that dose. Shaker said seven partial responses were initially confirmed, while additional pending responses had subsequently been confirmed. However, during the question-and-answer session, she said two remaining unconfirmed responses in the 6 mg/kg cohort would not be confirmed because those patients were off study.

The company also reported activity across several subgroups at the 6 mg/kg dose, including:

• A 50% response rate in RAS-mutant patients and 42% in RAS wild-type patients.
• A 43.5% response rate among patients previously treated with irinotecan.
• A 46.7% response rate in second- and third-line treatment and 42.9% in fourth-line and later treatment.

Shaker said patients in the analysis had a median follow-up of slightly more than four months. Several patients remained on treatment beyond six months, with some nearing or exceeding nine months.

Safety, dosing and pharmacokinetics

The most common treatment-related adverse events were hematological and gastrointestinal, including anemia, neutropenia, diarrhea, nausea, and reduced white blood cell and platelet counts. ArriVent said most adverse events were low grade, while higher-grade events occurred more frequently at higher doses.

At 6 mg/kg, the company reported a 2% rate of Grade 3 or higher diarrhea and low rates of severe hematological toxicities. There were two dose reductions and no treatment discontinuations due to adverse events at that dose level as of the cutoff, according to the presentation. Across dose escalation, the maximum tolerated dose was not reached. One dose-limiting toxicity occurred at 8 mg/kg, involving Grade 4 platelet reduction and Grade 4 neutropenia. No interstitial lung disease events were reported.

During the question-and-answer session, Shaker said higher doses were associated with increased cytopenias and diarrhea, which may have limited efficacy at those levels. The Phase Ib dose-optimization study is randomizing colorectal cancer patients between 5 mg/kg and 6 mg/kg. The company said it did not use prophylactic growth factor during dose escalation and does not plan to use it in Phase Ib.

ArriVent also said ARR-217 demonstrated dose-proportional pharmacokinetics, with low free-exatecan exposure that the company said suggested minimal systemic payload release.

Development plans and pipeline

Chief Executive Officer Bing Yao said ArriVent is initially targeting third-line and later colorectal cancer, where treatment options are limited. The ongoing Phase Ib monotherapy study is enrolling patients in the U.S. and China. Shaker said enrollment in the Phase Ib portion is expected to be more evenly balanced geographically than the overall study population.

ArriVent is also evaluating ARR-217 with bevacizumab and plans chemotherapy combination studies in China. Yao said adding bevacizumab could potentially improve either response rates or progression-free survival, though he said the ongoing studies will be needed to determine the effect.

The company expects to report additional Phase Ib monotherapy data in the first half of 2027, including durability and progression-free-survival information. It plans to provide initial data from the bevacizumab combination study in the second half of 2027 and initial chemotherapy-combination data by year-end. ArriVent is targeting the start of a Phase III trial by the end of 2027.

Beyond ARR-217, Yao said ArriVent recently enrolled the first patient in a Phase I study of ARR-002, a dual-targeting ADC directed at NaPi2b and MUC16. The company also continues enrollment in its global Phase III ALPACCA trial of firmonertinib in EGFR PACC-mutant non-small cell lung cancer and plans a program update in the first quarter of 2027.

About ArriVent BioPharma (NASDAQ:AVBP)

ArriVent BioPharma, Inc is a clinical-stage biopharmaceutical company focused on developing and commercializing precision oncology therapies for patients with genetically defined cancers. The company's primary focus is on targeted treatments for non-small cell lung cancer (NSCLC), particularly tumors driven by mutations in the epidermal growth factor receptor (EGFR) gene.

ArriVent's lead product candidate is furmonertinib, an oral, irreversible EGFR tyrosine kinase inhibitor designed to target a range of EGFR mutations, including common mutations and exon 20 insertion mutations.

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