Prognostic impact of reduced HER2 protein expression in post-neoadjuvant therapy resection specimens: A single institution experience and review of the literature.

BACKGROUND: Retesting for Human epidermal growth factor receptor-2 (HER2) in post-neoadjuvant therapy resection is variable, and data is conflicting regarding the prognostic significance of changes in HER2 expression pre and post therapy. METHODS: We identified 104 patients with localized HER2 IHC 3+ breast cancer who received neoadjuvant trastuzumab(T)/pertuzumab(P) containing chemotherapy at Yale Cancer Center between 2012 and 2022. Patients were divided into 3 cohorts by response and HER2 IHC in the residual disease: Cohort 1 pathologic complete response (pCR), Cohort 2 pre-treatment IHC 3+/post treatment IHC 1+/2+, and Cohort 3 pre-treatment IHC 3+/post-treatment IHC 3+. Kaplan-Meier survival analysis was performed to assess recurrence free survival at 36 months. RESULTS: The overall pCR rate was 62.5% (65/104), while 37.5% (39/104) of patients had residual disease (RD). Among patients with RD, 58.9% (23/39) remained IHC 3+ and 41.1% (16/39) had reduced HER2 expression IHC1+ or 2+. In patients with HER2 IHC 3+ RD, 26% (6/23) developed local recurrence or distant metastasis while none of patients with post NAT HER2 IHC 1+ or 2+ RD had relapse (p = 0.0309). In patients with pCR, 6.15% (4/65) had recurrence. Kaplan-Meier survival analysis revealed superior disease-free survival in patients with reduced HER2 IHC expression compared to those with remained IHC 3+ (log rank p = 0.004). CONCLUSION: We conclude that reduced HER2 expression by IHC following neoadjuvant treatment was associated with lower recurrence rates in HER2 IHC 3+ breast cancer. If confirmed, RD HER2 IHC expression could be used as a prognostic biomarker to stratify patients in adjuvant trials and identify patients who may benefit from more intensive adjuvant therapy and post therapy surveillance.

A phase 1b expansion study of TAS-102 with oxaliplatin for refractory metastatic colorectal cancer.

BACKGROUND: TAS-102, a novel antimetabolite, is approved for treatment of refractory metastatic colorectal cancer (CRC). This study sought to determine whether the addition of TAS-102 to oxaliplatin (TAS-OX) was safe and effective in metastatic CRC previously treated with oxaliplatin. METHODS: This investigator-initiated, open-label, single-arm phase 1b study enrolled patients with metastatic CRC previously treated with 5-fluorouracil, irinotecan, and oxaliplatin. In dose escalation, TAS-102 was given at 3 dose levels: 25, 30, and 35 mg/m2 twice daily on day 1 to day 5 with 85 mg/m2 oxaliplatin on day 1 in 14-day cycles. The primary endpoint of dose escalation was the recommended dose for expansion, and in dose expansion, the primary endpoint was overall response rate (ORR) according to the Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1). RESULTS: Forty-one patients were treated with TAS-OX. No dose-limiting toxicities were observed in the 11 patients treated in escalation. The recommended dose for expansion was 35 mg/m2 TAS-102 twice daily on day 1 to day 5 in combination with 85 mg/m2 oxaliplatin on day 1 in 14-day cycles. In the intention-to-treat population, the ORR was 2.4% (95% CI, 0%-12.9%) with 1 of 41 patients having a partial response, although 12 (29%) had tumor shrinkage. The median progression-free survival was 2.7 months (95% CI, 2.4-4.8 months) and median overall survival was 6.8 months (95% CI, 5.7-10 months). CONCLUSIONS: TAS-OX is safe with no unexpected toxicities at standard doses of each agent. The combination did not result in a clinically meaningful ORR, although progression-free survival and overall survival were encouraging in this heavily pretreated population. LAY SUMMARY: For metastatic colorectal cancer, the treatment combination of TAS-102 and oxaliplatin was found to be well-tolerated and revealed no unexpected side effects. Twelve of 41 patients had reductions in the size of their tumor, and the study treatment delayed the time to tumor growth as opposed to what would be expected.

Phase II Study of Modified FOLFOX6 With Bevacizumab in Metastatic Gastroesophageal Adenocarcinoma.

BACKGROUND: The median survival for patients with metastatic gastroesophageal adenocarcinoma is <12 months. Bevacizumab has demonstrated promising activity in metastatic gastroesophageal adenocarcinoma when used in combination with cisplatin-based regimens for patients from the Americas. We conducted a prospective phase II trial to investigate the efficacy of bevacizumab in combination with the oxaliplatin-based regimen, modified FOLFOX6, in patients with metastatic gastroesophageal adenocarcinoma. METHODS: Patients with untreated metastatic adenocarcinoma of the stomach, gastroesophageal junction, or distal esophagus received mFOLFOX6 (leucovorin 400 mg/m, fluorouracil 400 mg/m bolus and 2400 mg/m continuous infusion over 46 h, oxaliplatin 85 mg/m) and bevacizumab (10 mg/kg) every 2 weeks until disease progression or intolerance. Response by RECIST was evaluated by CT scan every 8 weeks. The primary objective was progression-free survival (PFS); secondary objectives were safety, response rate, and overall survival (OS). RESULTS: A total of 39 patients with untreated metastastic gastroesophageal adenocarcinoma were enrolled between September 2008 and June 2012. Median number of cycles administered was 12 (range, 4 to 86). The confirmed response rate was 56.4% (3 complete response and 19 partial response). The median PFS was 7.8 months and median OS was 14.7 months. Three patients remain on treatment, and 11 patients are alive, of whom 6 have survived >24 months. Treatment-related grade 3/4 toxicities included neutropenia (33.3%), neuropathy (20.5%), thromboembolism (VTE) (7.7%), thrombocytopenia (7.7%), anemia (2.6%), hypertension (2.6%), and proteinuria (2.6%). We observed no GI perforations or grade 3/4 GI hemorrhagic events. CONCLUSIONS: First-line mFOLFOX6 with bevacizumab for metastatic gastroesophageal adenocarcinoma was well tolerated and associated with longer PFS and OS compared with historical data from similar populations treated without bevacizumab. Our results suggest that the addition of bevacizumab to mFOLFOX6 may provide clinical benefit in American patients with metastatic gastroesophageal adenocarcinoma, a finding consistent with previous studies of first-line bevacizumab in combination with chemotherapy for this disease.

HOXB6 overexpression in murine bone marrow immortalizes a myelomonocytic precursor in vitro and causes hematopoietic stem cell expansion and acute myeloid leukemia in vivo.

The HOX family of homeobox genes plays an important role in normal and malignant hematopoiesis. Dysregulated HOX gene expression profoundly effects the proliferation and differentiation of hematopoietic stem cells (HSCs) and committed progenitors, and aberrant activation of HOX genes is a common event in human myeloid leukemia. HOXB6 is frequently overexpressed in human acute myeloid leukemia (AML). To gain further insight into the role of HOXB6 in hematopoiesis, we overexpressed HOXB6 in murine bone marrow using retrovirus-mediated gene transfer. We also explored structure-function relationships using mutant HOXB6 proteins unable to bind to DNA or a key HOX-binding partner, pre-B-cell leukemia transcription factor-1 (PBX1). Additionally, we investigated the potential cooperative interaction with myeloid ecotropic viral integration site 1 homolog (MEIS1). In vivo, HOXB6 expanded HSCs and myeloid precursors while inhibiting erythropoiesis and lymphopoiesis. Overexpression of HOXB6 resulted in AML with a median latency of 223 days. Coexpression of MEIS1 dramatically shortened the onset of AML. Cytogenetic analysis of a subset of HOXB6-induced AMLs revealed recurrent deletions of chromosome bands 2D-E4, a region frequently deleted in HOXA9-induced AMLs. In vitro, HOXB6 immortalized a factor-dependent myelomonocytic precursor capable of granulocytic and monocytic differentiation. These biologic effects of HOXB6 were largely dependent on DNA binding but independent of direct interaction with PBX1.