Dual anti-CTLA-4 and anti-PD-1 blockade in metaplastic carcinoma of the breast: (DART=Dual Anti-CTLA-4 & Anti-PD-1 blockade in Rare Tumors) (SWOG S1609, Cohort 36).

Abstract No : 1073

Abstract Type : Poster Session (Board #158)

Indication : Metaplastic breast cancer (MpBC)

Intervention : Dual anti-CTLA-4 and anti-PD-1 blockade

Company : U.S. National Institutes of Health, Pharmaceutical/Biotech Company

Technology : DART


Nineteen patients were registered to the cohort and seventeen eligible patients received therapy. The median age was 60 (range 26-85), most tumors were high grade, triple negative and had a high ki67 (median 87%), median prior therapy = 2 lines. The ORR was 12% (RECIST 1.1) and 18% (iRECIST), with ongoing responses at 23, 18 and 11 months, respectively; SD was seen in 24%, none . 6 months (Table). Median OS was 12 months. AEs were observed in 11 patients (65%), with 3 patients (18%) having Grade 3/4 AEs and 1 patient with a fatal AE (myocarditis). The most common toxicities were LFT abnormalities and fatigue.


Cohort 36 met its primary endpoint: ipilimumab plus nivolumab was clinically active in advanced MpBC, with durable responses observed in 3/17 patients. Further investigation of this combination is warranted.


In a rare breast cancer; Metaplastic breast cancer (MpBC) DART(Dual anti-CTLA-4 and anti-PD-1 blockade) results are consistent but still more data will be required in the future for further validation of this treatment.