Key Highlights

  • ArriVent BioPharma (NASDAQ:AVBP) traded about 18.07% lower, near USD 17.20, in early trading on Monday, October 26, 2026, after Sunday, October 25 data on its ARR-217 antibody-drug conjugate.
  • ARR-217, aimed at the CDH17 protein, showed a confirmed objective response rate of 44.8% (13 of 29 patients) in colorectal cancer at 6 mg/kg every three weeks, with disease control of 93.1%.
  • Grade 3 or higher treatment-related adverse events occurred in 30.1% of patients across doses, and the company expects further ARR-217 data in 2027.
  • Cash and investments were USD 373.1 million at June 30, 2026, with a runway into 2028, after the FURVENT Phase 3 miss on October 6.

A Reaction to Early ADC Data

ArriVent BioPharma (NASDAQ:AVBP), a clinical-stage oncology company, traded about 18.07% lower, near USD 17.20, in early trading on Monday, October 26, 2026. The company has not attributed the move to a specific event, but it presented initial Phase 1 data for ARR-217 at the European Society for Medical Oncology congress on Sunday, October 25, 2026, and scheduled a virtual webinar for Monday. At 6 mg/kg every three weeks, the confirmed objective response rate in colorectal cancer was 44.8% (13 of 29 patients) and disease control reached 93.1%. Grade 3 or higher treatment-related adverse events occurred in 30.1% of patients across doses. The shares had already fallen about 47% on Tuesday, October 6, 2026.

Why an Early Dataset Can Move the Shares

ArriVent (NASDAQ:AVBP) lost its lead programme case on October 6, when the FURVENT Phase 3 trial of firmonertinib in untreated EGFR exon 20 insertion lung cancer missed its primary endpoint. Median progression-free survival was 11.0 months at 240 mg and 8.4 months at 160 mg against 9.5 months for control, with a p-value of 0.0654 for the higher dose. That outcome left the pipeline value resting on earlier assets such as ARR-217. An antibody-drug conjugate links a cell-killing payload to an antibody that targets a tumour protein. Investors compare early response rates and safety with competing CDH17 candidates, so a 44.8% rate on 29 patients can be read either way.

Risks and What to Watch

The first risk for ArriVent (NASDAQ:AVBP) is that a Phase 1 sample of 29 colorectal patients is small, and responses may change as more patients are treated. The second is safety, since the 30.1% rate of grade 3 or higher events needs context from dose levels. The third is strategy: the company said it is evaluating the full FURVENT dataset to decide the path for firmonertinib. Law firms have also announced investigations on behalf of shareholders, which carry no finding. Investors should watch the webinar on Monday, October 26, 2026, the full firmonertinib analysis, the next quarterly results and the Federal Reserve decision on Wednesday, October 28, 2026.

Where Things Stand

The answer is that ArriVent (NASDAQ:AVBP) fell 18.07% in early trading on Monday, October 26, 2026 as investors weighed the first ARR-217 data after the FURVENT setback. The company holds USD 373.1 million of cash and investments with a runway into 2028, which limits near-term financing risk. The next catalysts are the webinar on Monday, October 26, the Federal Reserve decision on Wednesday, October 28 and the full firmonertinib decision. Early clinical data are not guarantees of later results, and this is not investment advice.