Tolerability of Eribulin and correlation between polymorphisms and neuropathy in an unselected population of female patients with metastatic breast cancer: results of the multicenter, single arm, phase IV PAINTER study.

BACKGROUND: Metastatic breast cancer (MBC) is an incurable disease and its treatment focuses on prolonging patients' (pts) overall survival (OS) and improving their quality of life. Eribulin is a microtubule inhibitor that increases OS in pre-treated MBC pts. The most common adverse events (AEs) are asthenia, neutropenia and peripheral neuropathy (PN). METHODS: PAINTER is a single arm, phase IV study, aimed at evaluating the tolerability of eribulin in MBC pts. Secondary objectives were the description of treatment efficacy and safety, the assessment of the incidence and severity of PN and its association with genetic polymorphisms. Genomic DNA was isolated from blood samples and 15 Single Nucleotide Polymorphisms (SNPs) were genotyped by Taqman specific assays. The association between PN and SNPs were evaluated by Fisher exact test. RESULTS: Starting from May 2014 until June 2018 180 pts were enrolled in this study by 20 Italian centers. 170 of these pts could be evaluated for efficacy and toxicity and 159 for polymorphisms analysis. The median age of pts was 60 years old and the biological subtypes were luminal type (64.7%), Her2 positive (18.3%) and triple negative (17%). Pts were pretreated with a median of 5 lines for MBC. The median follow up of this study was 15.4 months with a median number of 4.5 cycles administered (minimum-maximum 1-23). The median overall survival was 12 months. 48.8% of pts experienced a dose reduction, mainly for neutropenia (23.9%) and liver toxicity (12%). 65 pts (38.2%) reported at least one severe toxicity. Neutropenia and neurotoxicity were the most frequent severe AEs (15.3% and 14.7%, respectively); other reported toxicities were osteo-muscular, abdominal or tumor site pain (19.4%), liver toxicity (6.6%), pulmonary toxicity (6.5%) and dermatological toxicity (3.6%). Among the 15 evaluated SNPs, an association with PN was found for rs2233335 and rs7214723. CONCLUSIONS: Eribulin is a well-tolerated treatment option in MBC. Schedule and dosage modifications were common, but toxicity rarely led to treatment discontinuation. SNPs rs2233335 (G/T and T/T) in the NDRG1 gene and rs7214723 (CC and CT) in the CAMKK1 gene were associated with PN. These findings, if validated, could allow a tailored treatment with eribulin in cancer patients. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT02864030.

Immune microenvironment and intrinsic subtyping in hormone receptor-positive/HER2-negative breast cancer.

Little is known regarding the interaction between immune microenvironment and tumor biology in hormone receptor (HR)+/HER2- breast cancer (BC). We here assess pretreatment gene-expression data from 66 HR+/HER2- early BCs from the LETLOB trial and show that non-luminal tumors (HER2-enriched, Basal-like) present higher tumor-infiltrating lymphocyte levels than luminal tumors. Moreover, significant differences in immune infiltrate composition, assessed by CIBERSORT, were observed: non-luminal tumors showed a more proinflammatory antitumor immune infiltrate composition than luminal ones.

Prospective Biomarker Analysis of the Randomized CHER-LOB Study Evaluating the Dual Anti-HER2 Treatment With Trastuzumab and Lapatinib Plus Chemotherapy as Neoadjuvant Therapy for HER2-Positive Breast Cancer.

BACKGROUND: The CHER-LOB randomized phase II study showed that the combination of lapatinib and trastuzumab plus chemotherapy increases the pathologic complete remission (pCR) rate compared with chemotherapy plus either trastuzumab or lapatinib. A biomarker program was prospectively planned to identify potential predictors of sensitivity to different treatments and to evaluate treatment effect on tumor biomarkers. MATERIALS AND METHODS: Overall, 121 breast cancer patients positive for human epidermal growth factor 2 (HER2) were randomly assigned to neoadjuvant chemotherapy plus trastuzumab, lapatinib, or both trastuzumab and lapatinib. Pre- and post-treatment samples were centrally evaluated for HER2, p95-HER2, phosphorylated AKT (pAKT), phosphatase and tensin homolog, Ki67, apoptosis, and PIK3CA mutations. Fresh-frozen tissue samples were collected for genomic analyses. RESULTS: A mutation in PIK3CA exon 20 or 9 was documented in 20% of cases. Overall, the pCR rates were similar in PIK3CA wild-type and PIK3CA-mutated patients (33.3% vs. 22.7%; p = .323). For patients receiving trastuzumab plus lapatinib, the probability of pCR was higher in PIK3CA wild-type tumors (48.4% vs. 12.5%; p = .06). Ki67, pAKT, and apoptosis measured on the residual disease were significantly reduced from baseline. The degree of Ki67 inhibition was significantly higher in patients receiving the dual anti-HER2 blockade. The integrated analysis of gene expression and copy number data demonstrated that a 50-gene signature specifically predicted the lapatinib-induced pCR. CONCLUSION: PIK3CA mutations seem to identify patients who are less likely to benefit from dual anti-HER2 inhibition. p95-HER2 and markers of phosphoinositide 3-kinase pathway deregulation are not confirmed as markers of different sensitivity to trastuzumab or lapatinib. IMPLICATIONS FOR PRACTICE: HER2 is currently the only validated marker to select breast cancer patients for anti-HER2 treatment; however, it is becoming evident that HER2-positive breast cancer is a heterogeneous disease. In addition, more and more new anti-HER2 treatments are becoming available. There is a need to identify markers of sensitivity to different treatments to move in the direction of treatment personalization. This study identified PIK3CA mutations as a potential predictive marker of resistance to dual anti-HER2 treatment that should be further studied in breast cancer.

Double-blind, placebo-controlled, multicenter, randomized, phase IIb neoadjuvant study of letrozole-lapatinib in postmenopausal hormone receptor-positive, human epidermal growth factor receptor 2-negative, operable breast cancer.

PURPOSE: This is a randomized, double-blind, placebo-controlled study aimed to evaluate the clinical and biologic effects of letrozole plus lapatinib or placebo as neoadjuvant therapy in hormone receptor (HR) -positive/human epidermal growth factor receptor 2 (HER2) -negative operable breast cancer. METHODS: Ninety-two postmenopausal women with stage II to IIIA primary breast cancer were randomly assigned to preoperative therapy consisting of 6 months of letrozole 2.5 mg orally daily plus lapatinib 1,500 mg orally daily or placebo. Surgery was performed within 2 weeks from the last study medication. Clinical response was assessed by ultrasonography. Pre- and post-treatment samples were evaluated for selected biomarkers. Fresh-frozen tissue samples were collected for genomic analyses. RESULTS: Numerically similar clinical response rates (partial + complete response) were observed (70% for letrozole-lapatinib and 63% for letrozole-placebo). Toxicities were generally mild and manageable. A significant decrease in Ki-67 and pAKT expression from baseline to surgery was observed in both arms. Overall, 34 patients (37%) had a mutation in PIK3CA exon 9 or 20. In the letrozole-lapatinib arm, the probability of achieving a clinical response was significantly higher in the presence of PIK3CA mutation (objective response rate, 93% v 63% in PIK3CA wild type; P = .040). CONCLUSION: The combination of letrozole-lapatinib in early breast cancer was feasible, with expected and manageable toxicities. In unselected estrogen receptor-positive/HER2-negative patients, letrozole-lapatinib and letrozole-placebo resulted in a similar overall clinical response rate and similar effect on Ki-67 and pAKT. Our secondary end point findings of a significant correlation between PIK3CA mutation and response to letrozole-lapatinib in HR-positive/HER2-negative early breast cancer must now be independently confirmed.

Preoperative chemotherapy plus trastuzumab, lapatinib, or both in human epidermal growth factor receptor 2-positive operable breast cancer: results of the randomized phase II CHER-LOB study.

PURPOSE: This is a noncomparative, randomized, phase II trial of preoperative taxane-anthracycline in combination with trastuzumab, lapatinib, or combined trastuzumab plus lapatinib in patients with human epidermal growth factor receptor 2 (HER2) -positive, stage II to IIIA operable breast cancer. The primary aim was to estimate the percentage of pathologic complete response (pCR; no invasive tumor in breast and axillary nodes). PATIENTS AND METHODS: In the three arms, chemotherapy consisted of weekly paclitaxel (80 mg/m(2)) for 12 weeks followed by fluorouracil, epirubicin, and cyclophosphamide for four courses every 3 weeks. The patients randomly assigned to arm A received a 4-mg loading dose of trastuzumab followed by 2 mg weekly; in arm B patients received lapatinib 1,500 mg orally (PO) daily; and in arm C, patients received trastuzumab and lapatinib 1,000 mg PO daily. RESULTS: A total of 121 patients were randomly assigned. Diarrhea and dermatologic and hepatic toxicities were observed more frequently in patients receiving lapatinib. No episodes of congestive heart failure were observed. The rates of breast-conserving surgery were 66.7%, 57.9%, and 68.9% in arms A, B and C, respectively. The pCR rates were 25% (90% CI, 13.1% to 36.9%) in arm A, 26.3% (90% CI, 14.5% to 38.1%) in arm B, and 46.7% (90% CI, 34.4% to 58.9%) in arm C (exploratory P = .019). CONCLUSION: The primary end point of the study was met, with a relative increase of 80% in the pCR rate achieved with chemotherapy plus trastuzumab and lapatinib compared with chemotherapy plus either trastuzumab or lapatinib. These data add further evidence supporting the superiority of a dual-HER2 inhibition for the treatment of HER2-positive breast cancer.