Tumor-Infiltrating Lymphocytes in Triple Negative Breast Cancer: The Future of Immune Targeting

Triple negative breast cancer (TNBC) is a highly heterogeneous tumor. There is increasing evidence of the role of tumor lymphocytic immune infiltrates in this subtype of breast cancer. Robust levels of tumor infiltrating lymphocytes (TILs) have been associated with improved disease-free and overall survival rates in TNBC patients with and without any treatment. Recent efforts have been made to develop a standardized methodology for evaluating TILs. The presence of TILs in the breast tumor microenvironment can also predict responses not only to neoadjuvant but also to adjuvant chemotherapy treatments. High numbers of TILs correlate with increased pathological complete responses (pCR) in TNBC. TILs are prognostic and predictive of response to standard therapies; thus, the immune system appears to play an active role in a subgroup of breast cancer. There is an increasing interest in directly targeting the immune system as part of breast cancer therapy, mainly in patients with TNBC. New immune modulatory agents, including immune checkpoints inhibitors, have shown promising activity in a subgroup of metastatic TNBC. Increased programmed cell death protein 1 ligand (PD-L1) expression on the surface of TNBC provides the rationale for implementing therapeutic strategies targeting the PD-1/PD-L1 axis in TNBC. The programmed cell death protein 1 (PD-1) inhibitor pembrolizumab, and the PD-L1 inhibitor atezolizumab have shown promising results in clinical trials.

Patients' preferences for subcutaneous trastuzumab versus conventional intravenous infusion for the adjuvant treatment of HER2-positive early breast cancer: final analysis of 488 patients in the international, randomized, two-cohort PrefHer study

BACKGROUND

Patients with HER2-positive early breast cancer (EBC) preferred subcutaneous (s.c.) trastuzumab, delivered via single-use injection device (SID), over the intravenous (i.v.) formulation (Cohort 1 of the PrefHer study: NCT01401166). Here, we report patient preference, healthcare professional satisfaction, and safety data pooled from Cohort 1 and also Cohort 2, where s.c. trastuzumab was delivered via hand-held syringe.

PATIENTS AND METHODS

Patients were randomized to receive four adjuvant cycles of 600 mg fixed-dose s.c. trastuzumab followed by four cycles of standard i.v. trastuzumab, or vice versa. The primary endpoint was overall preference proportions for s.c. or i.v., assessed by patient interviews in the evaluable ITT population.

RESULTS

A total of 245 patients were randomized to receive s.c. followed by i.v. and 243 received i.v. followed by s.c. (evaluable ITT populations: 235 and 232 patients, respectively). s.c. was preferred by 415/467 [88.9%; 95% confidence interval (CI) 85.7-91.6; P < 0.0001; two-sided test against null hypothesis of 65% s.c. preference]; 45/467 preferred i.v. (9.6%; 95% CI 7-13); 7/467 indicated no preference (1.5%; 95% CI 1-3). Clinician-reported adverse events occurred in 292/479 (61.0%) and 245/478 (51.3%) patients during the pooled s.c. and i.v. periods, respectively (P < 0.05; 2 × 2 χ(2)); 16 patients (3.3%) in each period experienced grade 3 events; none were grade 4/5.

CONCLUSIONS

PrefHer revealed compelling and consistent patient preferences for s.c. over i.v. trastuzumab, regardless of SID or hand-held syringe delivery. s.c. was well tolerated and safety was consistent with previous reports, including the HannaH study (NCT00950300). No new safety signals were identified compared with the known i.v. profile in EBC. PrefHer and HannaH confirm that s.c. trastuzumab is a validated and preferred option over i.v. for improving patients' care in HER2-positive breast cancer.

CLINICALTRIALSGOV REGISTRATION NUMBER

NCT01401166.