Triple-negative breast cancer (TNBC) is associated with high recurrence rates, high incidence of distant metastases, and poor overall survival (OS). Taxane and anthracycline-containing chemotherapy (CT) is currently the main systemic treatment option for TNBC, while platinum-based chemotherapy showed promising results in the neoadjuvant and metastatic settings. An early arising of intrinsic or acquired CT resistance is common and represents the main hurdle for successful TNBC treatment. Numerous mechanisms were uncovered that can lead to the development of chemoresistance. These include cancer stem cells (CSCs) induction after neoadjuvant chemotherapy (NACT), ATP-binding cassette (ABC) transporters, hypoxia and avoidance of apoptosis, single factors such as tyrosine kinase receptors (EGFR, IGFR1), a disintegrin and metalloproteinase 10 (ADAM10), and a few pathological molecular pathways. Some biomarkers capable of predicting resistance to specific chemotherapeutic agents were identified and are expected to be validated in future studies for a more accurate selection of drugs to be employed and for a more tailored approach, both in neoadjuvant and advanced settings.
| A. | |||||||
|---|---|---|---|---|---|---|---|
| Drug | Target/Mechanism of Action | CS/ES | Outcome | Reference/NCT Number | |||
| Currently recommended | |||||||
| Olaparib | PARP inhibitor | Metastatic, in HER2 negative BC pts with a germline | BRCA | mutation (CS) | Higher objective RR and PFS | [165] | [13] |
| Talazoparib | Advanced, in BC pts with germline | BRCA | mutation (CS) | [166] | [14] | ||
| Larotrectinib | Inhibitor of tropomyosin receptor kinase (TRK) | Advanced, in NTRK gene fusion-positive solid tumours (CS) | ORR 71% | [170] | [20] | ||
| Entrectinib | ORR 57%; Median duration of response 10 months | [172] | [22] | ||||
| Sacituzumab govitecan | Anti-Trop2 antibody drug conjugate | Metastatic, in heavily pretreated pts (CS) | RR 33.3%; median duration of response 7.7 months; clinical benefit rate 45.4%; median PFS 5.5 months; OS 13.0 months | [184] | [34] | ||
| Under investigation | |||||||
| Galunisertib | TGF beta type I receptor inhibitor | Metastatic, in combination with CT (CS) | NA | NCT02672475 (phase I) | |||
| PF-03084014 | Gamma secretase inhibitor | Advanced, in combination with docetaxel (CS) | Median PFS 4.1 months | [186] | [39] | ||
| AL101 | Patient-derived xenografts with abnormal Notch signaling (ES) | Inhibition of tumor growth | [185] | [35] | |||
| SRI33576, SRI35889 | wnt/beta-catenin inhibitors | Cell lines (ES) | Pro-apoptotic effects by downregulating LRP6 | [187] | [40] | ||
| Salinomycin | Breast CSCs (ES) | inhibition of proliferation, invasion, and self-renewal while inducing apoptosis | [185,186] | [35][39] | |||
| CWP232228 | Xenograft models (ES) | Inhibition of tumor growth | [54] | [42] | |||
| Clofazimine | Cells and xenograft models (ES) | inhibition of proliferation; | [189] | [43] | |||
| Frizzled-7 protein antagonist (rhFzd7) | Cells and xenografts (ES) | Inhibition of proliferation, invasion, and angiogenesis while sensitizing cells to docetaxel | [190] | [44] | |||
| LGK974 | Advanced, in pts with wnt-ligand dependent malignancies, including TNBC (CS) | NA | NCT01351103 (phase I) | ||||
| PTK7-ADC | Metastatic, in combination with gedatolisib (dual PI3K-mTORC1/2 inhibitor) (CS) | NCT03243331 (phase I) | |||||
| B. | |||||||
| Drug | Target/Mechanism of Action | CS/ES | Outcome | Reference/NCT Number | |||
| Under investigation | |||||||
| GANT61 | Hh/direct GLI inhibitor | Cell lines (ES) | promoted apoptosis, reduced proliferation, and decreased CSC population | [192,193] | [46][47] | ||
| Plumbagin | Non-specific NF-kB inhibitor | Decreased cell viability and promoted apoptosis | [195] | [49] | |||
| Genistein | NF-kB inhibitor | Anti-growth and pro-apoptotic effects | [196] | [50] | |||
| DHMEQ | Nuclear translocation of NF-B inhibitor | Decreased growth and induction of apoptosis | [197] | [51] | |||
| Everolimus | mTOR inhibitor | Advanced, in combination with carboplatin (CS) | NA | NCT02531932 (phase II) | |||
| Advanced, in combination with cisplatin (CS) | NCT01931163 (phase II) | ||||||
| BKM120 | PI3K inhibitor | Metastatic (CS) | NCT01629615 (phase II) | ||||
| Alpelisib | Neoadjuvant, in combination with nab-paclitaxel in anthracycline refractory pts with PIK3CA or PTEN alterations (CS) | NCT04216472 (phase I) | |||||
| Ipatasertib | AKT inhibitor | Locally advanced/metastatic, first line (phase II), in combination with paclitaxel (CS) | Prolonged PFS and OS | [198] | [53] | ||
| Ipatasertib | Advanced, in PIK3CA/AKT1/PTEN-altered pts, in combination with paclitaxel versus placebo + paclitaxel (CS) | NA | NCT03337724 (phase III) | ||||
| Uprosertib | Metastatic, in combination with trametinib (CS) | NCT01964924 (phase II) | |||||
| AZD5363 | Metastatic, in combination with CT (CS) | Prolonged OS | [201] | [56] | |||
| Ruxolitinib | JAK1/2 inhibitor | Neoadjuvant, in combination with CT (CS) | NA | NCT02876302 (phase II) | |||
| C. | |||||||
| Drug | Target/Mechanism of Action | CS/ES | Outcome | Reference/NCT Number | |||
| Under investigation | |||||||
| AZD9150 | Antisense nucleotide inhibitor of | STAT3 | Metastatic, in combination with durvalumab and paclitaxel (CS) | NA | NCT03742102 (phase I/II) | ||
| MEDI3039 | Apoptosis/DR agonist | In-vitro and in-murine models (ES) | Tumor growth inhibition | [205] | [60] | ||
| Debio 1143 | IAP antagonist | Advanced, solid tumors including TNBC (CS) | NA | NCT01078649, NCT01930292 (phase I) | |||
| LCL161 | SMAC analog | Neoadjuvant, in combination with paclitaxel (CS) | Doubled pCR rate in a group preselected for the tumor necrosis factor ( | TNF | ) gene expression profile | [205] | [60] |
| antisense-miRNA-21 and antisense-miRNA-10b co-delivery | Inhibition of oncogenic miRNAs | Murine models (ES) | reduced tumor growth | [207] | [62] | ||
| miR-mimic recombinant vectors | Restoration of tumor suppressor miRNAs | Cell line (ES) | Reduced migration and invasion | [209] | [64] | ||
| Panitumumab | anti-EGFR mAb | Neoadjuvant, in combination with CT | NA | NCT02876107 (phase II) NCT01036087 (phase II) |
|||
| Apatinib | Anti-EGFR TKI | Advanced, alone or in combination with CT (CS) | NCT05019690 (phase I/II) NCT03932526 (phase II) NCT03254654 (phase II) |
||||
| Icotinib | Metastatic, pre-treated (CS) | Under evaluation | NCT02362230 (phase II) | ||||
| Bicalutamide | AR antagonist | Metastatic, AR-positive (CS) | six-month CBR 19%, median PFS 12 weeks | [221] | [79] | ||
| Abiraterone acetate | Advanced or metastatic, AR-positive pts, in combination with prednisone (CS) | six-month CBR 20.0%, ORR 6.7%, median PFS 2.8 months | [222] | [80] | |||
| Enzalutamide | Locally advanced or metastatic AR-positive pts (CS) | 16 weeks CBR 33%, median PFS 3.3 months, median OS 17.6 months | [223] | [81] | |||
| Darolutamide | Locally recurrent or metastatic, in AR-positive pts (CS) | NA | NCT03383679 (phase II) | ||||