T-cell bispecific antibodies in node-positive breast cancer: novel therapeutic avenue for MHC class I loss variants.

BACKGROUND: Tumor-infiltrating lymphocytes (TILs) represent a prognostic factor for survival in primary breast cancer (BC). Nonetheless, neoepitope load and TILs cytolytic activity are modest in BC, compromising the efficacy of immune-activating antibodies, which do not yet compete against immunogenic chemotherapy. PATIENTS AND METHODS: We analyzed by functional flow cytometry the immune dynamics of primary and metastatic axillary nodes [metastatic lymph nodes (mLN)] in early BC (EBC) after exposure to T-cell bispecific antibodies (TCB) bridging CD3ε and human epidermal growth factor receptor 2 (HER2) or Carcinoembryonic Antigen-Related Cell Adhesion Molecule 5 (CEACAM5), before and after chemotherapy. Human leukocyte antigen (HLA) class I loss was assessed by whole exome sequencing and immunohistochemistry. One hundred primary BC, 64 surrounding 'healthy tissue' and 24 mLN-related parameters were analyzed. RESULTS: HLA loss of heterozygosity was observed in EBC, at a clonal and subclonal level and was associated with regulatory T cells and T-cell immunoglobulin and mucin-domain-3 expression restraining the immuno-stimulatory effects of neoadjuvant chemotherapy. TCB bridging CD3ε and HER2 or CEACAM5 could bypass major histocompatibility complex (MHC) class I loss, partially rescuing T-cell functions in mLN. CONCLUSION: TCB should be developed in BC to circumvent low MHC/peptide complexes.

A gene signature to predict high tumor-infiltrating lymphocytes after neoadjuvant chemotherapy and outcome in patients with triple-negative breast cancer.

Background: In patients with triple-negative breast cancer (TNBC), the extent of tumor-infiltrating lymphocytes (TILs) in the residual disease after neoadjuvant chemotherapy (NACT) is associated with better prognosis. Our objective was to develop a gene signature from pretreatment samples to predict the extent of TILs after NACT and then to test its prognostic value on survival. Patients and methods: Using 99 pretreatment samples, we generated a four-gene signature associated with high post-NACT TILs. Prognostic value of the signature on distant relapse-free survival (DRFS) was first assessed on the training set (n = 99) and then on an independent validation set (n = 115). Results: A four-gene signature combining the expression levels of HLF, CXCL13, SULT1E1, and GBP1 was developed in baseline samples to predict the extent of lymphocytic infiltration after NACT. In a multivariate analysis performed on the training set, this signature was associated with DRFS [hazard ratio (HR): 0.28, for a one-unit increase in the value of the four-gene signature, 95% confidence interval (CI): 0.13-0.63)]. In a multivariate analysis performed on an independent validation set, the four-gene signature was significantly associated with DRFS (HR: 0.17, 95% CI: 0.06-0.43). The four-gene signature added significant prognostic information when compared with the clinicopathologic pretreatment model (likelihood ratio test in the training set P = 0.004 and in the validation set P = 0.002). Conclusions: A four-gene signature predicts high levels of TILs after anthracycline-containing NACT and outcome in patients with TNBC and adds prognostic information to a clinicopathological model at diagnosis.

MOVIE: a phase I, open-label, multicenter study to evaluate the safety and tolerability of metronomic vinorelbine combined with durvalumab plus tremelimumab in patients with advanced solid tumors.

BACKGROUND: Anti-programmed cell death protein 1 (PD1)/programmed death-ligand 1 (PD-L1) agents have only moderate antitumor activity in some advanced solid tumors (AST), including breast cancer (BC), prostate cancer (PC), cervical cancer (CC), and head and neck cancer (HNC). Combining anti-PD-L1 with anti-cytotoxic T-lymphocyte-associated protein (CTLA) and chemotherapy may significantly improve efficacy. PATIENTS AND METHODS: MOVIE is a multicohort phase I/II study examining the combination of anti-PD-L1 durvalumab (Durv; 1500 mg IV Q4W) plus anti-CTLA tremelimumab (Trem; 75 mg IV Q4W) with metronomic vinorelbine (MVino; 20-40 mg orally daily) in various AST resistant to conventional therapies. The primary objective of the phase I part was to determine the maximum tolerated dose (MTD) and recommended dose for phase II (RP2D). RESULTS: Among the 14 patients enrolled during phase I, including 13 women and 1 man, 9 had BC, 1 PC, 2 CC, and 2 miscellaneous cancers with high mutational loads. Median age was 53 years. A total of 12 patients were assessable for the dose-escalation part in which only one dose-limiting toxicity (DLT) was observed [one neutropenia without fever, grade (G) 4]. Two (14.3%), four (28.6%), and four (28.6%) patients had G ≥3 adverse events (AEs) related to MVino, Durv, and Trem, respectively. Treatment-related events included mostly clinical AEs with asthenia (eight G2; three G3), colitis (one G2, one G3), diarrhea (one G3), nausea (two G2), dry skin (two G2), maculopapular rash (one G3), and hyperthyroidism (three G2). No toxic death was reported. Preliminary data showed one patient (CC) who presented a complete response and four patients with stable disease (SD). CONCLUSIONS: MTD was not reached and dose level 2 (MVino 40 mg, Durv 1500 mg, Trem 75 mg) was selected as RP2D. The safety profile of the combination was manageable and consistent with previous reports of Trem + Durv or MVino. Phase II is currently ongoing in BC, PC, CC, HNC, and miscellaneous cohorts.