The use of immunotherapy to treat metastatic breast cancer

Breast cancer, in the stage with distant metastases, is an incurable disease with a 5 years survival rate of about 5-10% (1). Immunotherapy has recently improved survival in metastatic breast cancer patients with breast cancer harbouring the expression of HER 2 receptor. Particularly in HER 2 positive patients pertuzumab plus trastuzumab and docetaxel is the recommended first line regimen and in triple negative breast cancer patients (TNBC) bevacizumab plus paclitaxel or docetaxel is a reasonable option. In the metastatic breast cancer patients responding to conventional antiestrogens without or with HER 2 receptor, the addition of interferon beta-interleukin 2 sequence importantly prolongs quality and length of survival in a pilot study of 42 patients. In fact, in all patients median progression-free survival (PFS) from the beginning of hormone-therapy was 33 months, (Fig.1) and median OS 82 months (Fig 2); cumulative survival at 5 and 10 years±SE were 0.69±0.07 and 0.15±0.06 respectively. In the overall population these data confirm the previously reported findings (2-4). In the luminal sub-type, median PFS was 33 months (Fig.3) and median OS was 91 months (Fig 4). In the non-luminal sub-type, median PFS was 32 months and median OS was 59 months. Therefore, a relevant PFS and OS improvement occurred both in luminal and in non-luminal molecular subtypes compared with that expected in similar populations. In fact, equal or less than 10 months [5-6] is the reported median PFS in non-luminal breast cancer patients and it ranges from 11.2 months [7] to 15.6 months [8] in luminal patients. Moreover, 30.6 and 24.4 months have been reported as the best median OS in luminal and non-luminal breast cancer patients respectively [9]. In some observational or phase I/II studies on HER 2 peptide/protein vaccines promising although preliminary findings have been reported.