Agents targeting HER2 arepromising and the best studied therapies in patients with HER2-positive salivary duct carcinoma (SDC). RC48-ADC (Disitamab vedotin) is a novel humanized anti-HER2 antibody-drug conjugate (ADC). But the efficacy and safety of RC48-ADC is still unknown in metastatic SDC with HER2-positive.
Eligible patients from Zhejiang Cancer Hospital were 35∼76 years old, with confirmed, histologically HER2 expression (IHC1+, 2+, 3+), metastatic SDC. Patients had at least one line of systemic chemotherapy. Patients received RC48-ADC at 1.5 or 2 mg/kg, every two weeks. Clinical efficacy and safety were assessed.
This study enrolled HER2-expressing metastatic SDC patients from June 2022 to Dec 2022. 10 mSDC patients (8 males, 2 females) were enrolled. 90% patients had received ≥2 lines systemic chemotherapy. 80% patients had visceral metastases. As of 05 Jan 2023 (data cutoff), 1 patient achieved CR, 4 patients achieved PR, 4 patients achieved SD, and only 1 patient achieved PD. The overall confirmed DCR was 90%. Most common treatment-related AEs were hypoaesthesia (70%), asthenia (60%), leukopenia (30%), decreased appetite (20%), alopecia (10%). The grade≥3 TRAEs only included hypoaesthesia (30.0%) and neutropenia (10%).
RC48-ADC showed a promising efficacy with a manageable safety profile in HER2-expressing mSDC patients who had failed at least one line of systemic chemotherapy.
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