# A166

Source: https://onco.cc/drugs/a166/  
OnCo record `a166` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A166 is an experimental antibody-drug conjugate from Sichuan Kelun-Biotech Biopharmaceutical in phase 3 trials for HER2-positive breast cancer, aimed at HER2.

## Summary

A166 is an antibody-drug conjugate developed by Sichuan Kelun-Biotech Biopharmaceutical. Its target is HER2 (the sponsor names HER2). The sponsor states: A166 is a HER2-targeted antibody-drug conjugate with a microtubule inhibitor payload, administered intravenously at 4.8 mg/kg every three weeks (Q3W) to HER2-positive breast cancer patients. It is the investigational product in 2 recruiting or active industry-led phase 2 and phase 3 interventional cancer trials, including the phase 3 study NCT06968585 (A Study of A166 Versus Trastuzumab Emtansine (T-DM1) in Patients With HER2-Positive Unresectable or Metastatic Breast Cancer Previously Treated With Trastuzumab and Taxane Therapy), in HER2-positive breast cancer. The largest, NCT06968585, plans to enrol 365 participants (actual) with primary completion expected 2026-11-30. Status reflects the highest phase registered on ClinicalTrials.gov; no efficacy results are recorded here.

## Fields

- Kind: Treatment
- Status: phase-3
- Last checked: 2026-09-11
- Tags: pipeline; ctgov-ingest
- Modality: ADC
- Mechanism: A166 is a HER2-targeted antibody-drug conjugate with a microtubule inhibitor payload, administered intravenously at 4.8 mg/kg every three weeks (Q3W) to HER2-positive breast cancer patients.

## Sources

- ClinicalTrials.gov: trials of A166: https://clinicaltrials.gov/search?intr=A166

## Connected records

- cancers: [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/)
- targets: [HER2](https://onco.cc/targets/her2/)
- companies: [Sichuan Kelun-Biotech](https://onco.cc/companies/kelun-biotech/)
- trials: [A Study of A166 in Patients With HER2-Positive Unresectable or Metastatic Breast Cancer](https://onco.cc/trials/nct07299825/), [A Study of A166 Versus Trastuzumab Emtansine (T-DM1) in Patients With HER2-Positive Unresectable or Metastatic Breast Cancer Previously Treated With Trastuzumab and Taxane Therapy](https://onco.cc/trials/nct06968585/)

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