Direct estrogen receptor (ER) / HER family crosstalk mediating sensitivity to lumretuzumab and pertuzumab in ER+ breast cancer
Fig 2
Lumretuzumab plus pertuzumab induces long-lasting tumor remission and inhibits HER2/HER3 signaling in estrogen-dependent breast cancer.
(A) Outbred athymic (nu/nu) female mice (n = 10 per treatment group) bearing ER+/HER2-low/HER3+ human breast cancer xenografts (HBCx-19) were treated with single-agent lumretuzumab (10 mg/kg i.p.), single-agent pertuzumab (15 mg/kg i.p. with a two-fold loading dose), the combination of both antibodies, or with vehicle only (control). All treatments were given weekly beginning on Day 26 when median tumor size was 100–150 mm3 for 6 weeks (until Day 61). (B) Longer term follow-up of the mice depicted in Fig 1A showed that remissions in mice treated with lumretuzumab plus pertuzumab were long-lasting after the final dose of combination therapy on Day 61 (black arrow). Inhibition of MAPK (C) and AKT (D) in tumors harvested from mice on Day 94 (Day 40 for vehicle controls) was greatest with combination therapy.