F49 - Pertuzumab, Trastuzumab, Docetaxel: a single istitution clinical exeperience for Her2 positive metastatic breast cancer (mBC)

Abstract

Background: Pertuzumab is a novel, humanized monoclonal antibody that inhibits the dimerization of the receptor Her2. Recent clinical studies have shown that the association of trastuzumab (T) and pertuzumab (P) to docetaxel (D) is very effective in Her2 positive mBC not previously treated for metastatic disease. Material and methods: From November 2013 to March 2016 we treated 18 consecutive pazients (pts) with mBC. The schedule used at our institution was: Pertuzumab 420 mg (840 mg loading dose,) Trastuzumab 6 mg/kg (8 mg loading dose), Docetaxel 75 p.m.s. (100 p.s.m. if well tolerated), every 21 days. All the pts continued with P + T maintenance until progression or intollerable toxicity. Median age was 54 at observation of metastatic disease. 3/18 pts were de novo metastatic, 2/18 have had neoadjuvant chemotherapy, 13/18 adjuvant. All the pts treated in neo/adiuvant setting had been treated with T. 8/18 were hormone receptor positive and 7/18 received ormonotherapy in adjuvant setting. Metastatic sites were: 3/18 brain, 6/18 lung, 7/18 liver, 8/18 bone, 13/18 soft/tissue, linphnodes. Results: 17/18 received the planned schedule for 8-9 cycles and then continued with maintenance therapy consisting in P + T whereas 1 patient suspended the treatment after the second cycle due to repeated reaction of intolerance G3 and was no evaluable for response. Mean cycles delivered were 17,9. 2/17 pts experienced progressive disease after 8 and 10 cycles respectively, and underwent trastuzumab-emtansine therapy as subsequently line of therapy. 2/17 pts had complete response (1 pts lung and liver, 1 pts lung, liver and breast), 7/17 had major partial response (visceral metastases), 6/17 stable disease. 15/18 pts are still on treatment with P + T and are still on response. 5/17 pts exceeded 40 cycles of treatment. We observed no episodes of cardiac toxicity or LFEV reduction. Neutropenia G3-G4 in 5/17 pts (2 G4 supported with (G-CSF), Diarrhea G2-G3 in 7/17 pts, erithema, mucositis and nail damage 7/17. 7/17 pts tolerated docetaxel at the full dose of 100 p.s.m. Conclusion: Our experience confirm that patients with overexpressing Her2-mBC may derive from the exposure to P and T plus D high rates of responses whit a good toxicity profile, in fact, the regimen is well tolerated, expecially if D is administered at the dose of 75 mg p.s.m.