Alison K. Conlin

Phase II Trial of Weekly Nanoparticle Albumin-Bound Paclitaxel With Carboplatin and Trastuzumab as First-line Therapy for Women With HER2-Overexpressing Metastatic Breast Cancer

PURPOSE This multicenter phase II trial evaluated the efficacy and safety of weekly nanoparticle albumin-bound paclitaxel with carboplatin and weekly trastuzumab as first-line therapy for women with HER2-overexpressing metastatic breast cancer (MBC). PATIENTS AND METHODS We treated 32 patients who had measurable MBC that was HER2-positive defined by an immunohistochemical staining score of 3+ or gene amplification by fluorescence in situ hybridization, required for those with an IHC of 2+. Patients were treated with albumin-bound paclitaxel 100 mg/m2 and carboplatin at area under the curve (AUC) = 2 on days 1, 8, and 15 of a 28-day cycle. Trastuzumab was administered at 2 mg/kg weekly after a loading dose of 4 mg/kg. Because of hypersensitivity reactions occurring during carboplatin infusion numbers 6-8 in 4 of the first 13 patients with this premedication-free regimen, the protocol was amended for carboplatin and dosed at AUC = 6 day 1 each 28-day cycle, in lieu of introducing steroid prophylaxis. Patients were treated with 6 cycles and allowed to continue with all 3 drugs or trastuzumab alone if free of progression and unacceptable toxicity after 6 cycles. RESULTS The overall response rate (ORR) was 62.5% (95% CI, 45.7%-79.3%) with 3 confirmed complete responders (CRs; 9%) and 17 confirmed partial responses (PRs; 53%). An additional 6 patients (19%) had stable disease (SD) for greater than 16 weeks for a clinical benefit rate (ORR + SD > 16 weeks) of 81%. As of April 16, 2009, 20 patients (63%) had progressed with a median progression-free survival (PFS) of 16.6 months (95% CI, 7.5-26.5 months). Antitumor activity was similar for patients treated with weekly carboplatin and every-4-week carboplatin (ORR, 65% vs. 67%, respectively). Hematologic toxicities were the only grade 4 toxicities noted and were infrequent with grade 4 neutropenia in 3 patients (9%) and 1 febrile neutropenia. Grade 2/3 peripheral neuropathy was uncommon (13%/3%). CONCLUSION Weekly albumin-bound paclitaxel with carboplatin and trastuzumab is highly active in HER2-overexpressing MBC. In the absence of corticosteroid premedication, which we avoided with albumin-bound paclitaxel, carboplatin seems best dosed every 4 weeks rather than weekly because of carboplatin-associated hypersensitivity reactions. The regimen was very well tolerated with few grade 3 and 4 nonhematologic toxicities experienced, and severe hematologic toxicity and peripheral neuropathy were infrequent.

Taxanes in breast cancer: An update

Over the past decade the taxanes have proved to be fundamental in the treatment of breast cancer. Initially found to have efficacy in metastatic breast cancer, the taxanes are now vital components in the treatment of early-stage disease, in which their addition to adjuvant treatment of early breast cancer has been shown to improve overall survival. In addition, the taxanes have demonstrated a role in first-line therapy for metastatic disease, with some of the highest efficacy of any class of chemotherapy. Targeted therapies in combination with the taxanes have further improved survival for both early and metastatic disease. New formulations of taxanes may both improve antitumor activity and reduce toxicity.

Beyond Cytotoxic Chemotherapy for the First-Line Treatment of HER2-Negative, Hormone-Insensitive Metastatic Breast Cancer: Current Status and Future Opportunities

As reflected in its varied clinical behavior, appearances under the light microscope, and differential patterns of gene expression, metastatic breast cancer (MBC) is a heterogeneous disease. Systemic treatment decisions are guided by specific tumor characteristics and individual patient factors. For patients with hormone receptor (HR)-negative MBC and for those whose HR-positive disease has become refractory to hormonal therapies, cytotoxic chemotherapy has been the mainstay of systemic treatment. For hormone-insensitive, HER2-positive MBCs, the addition of trastuzumab to chemotherapy has resulted in improved outcomes. Hormone-insensitive MBC lacking HER2 overexpression includes the subset of patients with estrogen receptor/ progesterone receptor/HER2-negative (so-called triple-negative) disease, which represents a significant minority of all breast cancers. Therapeutic options for such patients are limited by the lack of specific targeted approaches, and this heterogeneous group will be considered collectively as well as separately in this overview of existing and emerging treatment strategies. Conventional cytotoxic chemotherapy, alone or in combination, has been the standard first-line treatment for patients with MBC not amenable to antiestrogen or trastuzumab therapy. The recent evaluation of new targeted therapies in combination with cytotoxic agents has created a new type of combination regimen. Agents targeting angiogenesis, the epidermal growth factor receptor, and various signal transduction pathways have been combined with chemotherapy and possess biologic activity in MBC. As these combinations are being investigated, parallel correlative studies aimed at enriching the population who will benefit most are under way.

Randomized Phase II Trial of Weekly vs. Every 2 Weeks vs. Every 3 Weeks Nanoparticle Albumin- Bound Paclitaxel With Bevacizumab as First-Line Chemotherapy for Metastatic Breast Cancer

BACKGROUND Nanoparticle albumin-bound paclitaxel (nab-P) and bevacizumab have each demonstrated efficacy in patients with MBC. This trial was designed to further develop nab-P by evaluating its efficacy and safety using every 3 weeks (q3w), every 2 weeks (q2w), or weekly scheduling in combination with bevacizumab as first-line treatment of MBC. PATIENTS AND METHODS This open-label phase II study randomized patients to nab-P 260 mg/m(2) q3w (arm A) vs. 260 mg/m(2) q2w with filgrastim (arm B) vs. 130 mg/m(2) weekly uninterrupted, all with bevacizumab (15 mg/kg q3w arm A, 10 mg/kg q2w arms B and C). The primary endpoints were overall response rate (ORR) and toxicity. Time to tumor progression (TTP) and overall survival were secondary endpoints. RESULTS Of 212 patients randomized, 208 (arm A, 75; arm B, 54; arm C, 79) were treated. Arm B was closed early due to toxicity, with more grade ≥ 2 fatigue (arm A, 46%; arm B, 62%; arm C, 62%) and bone pain (arm A, 11%; arm B, 23%; arm C, 5%). Neurotoxicity grade ≥ 2 was equivalent across the arms (> 50%) and reversible for most patients. Febrile neutropenia occurred in ≤ 3% of patients in all arms. ORR was similar among the arms (arm A, 45%; arm B, 41%; arm C, 46%). Median TTP was slightly longer in arm C (9.0 months) vs. arms A (8.0 months) and B (5.8 months) (overall, P = .105). CONCLUSIONS Significant antitumor activity was observed in all the arms. Weekly nab-P with bevacizumab appeared to have the highest therapeutic index. However, sensory neuropathy was treatment limiting, which suggests that a 3 weeks on and 1 week off schedule should be explored.

Use of the Oncotype DX 21-gene assay to guide adjuvant decision making in early-stage breast cancer.

The decision to use adjuvant chemotherapy in patients with early stage breast cancer involves the consideration of many factors that traditionally rely heavily on tumor size and lymph node involvement and a limited set of biologic characteristics such as estrogen receptor and HER2 expression. Overtreatment with cytotoxic chemotherapy is a significant concern among patients and physicians. Using the currently accepted guidelines it has been estimated that a large percentage of patients receiving chemotherapy for low-risk breast cancers may be overtreated. Gene expression profiling is a new technology being developed to help improve risk stratification of patients and to predict outcomes. The Oncotype DX™ assay is one example of a gene expression profile validated in women with lymph node-negative, estrogen receptor-expressing breast cancer. This assay and others aim to help improve risk classification and recurrence prediction and, therefore, optimize selection of patients for adjuvant chemotherapy.

Phase II trial of patupilone in patients with brain metastases from breast cancer

BACKGROUND For patients with progressive breast cancer brain metastasis (BCBM) after whole brain radiotherapy (WBRT), few options exist. Patupilone is an epothilone that crosses the blood-brain barrier. We hypothesized that patupilone would produce a 35% 3-month CNS progression-free survival in women with BCBM after WBRT. METHODS This multicenter phase II trial included 2 cohorts. Group A included women with progressive BCBM after WBRT. Group B was an exploratory cohort of patients with either leptomeningeal metastases or untreated brain metastases. The primary goal was to observe a 35% 3-month CNS progression-free survival in Group A. The sample size was 45 for Group A and 10 for Group B. Patients received patupilone 10 mg/m(2) once every 3 weeks until progression. Responses were scored according to the Macdonald criteria. RESULTS Fifty-five patients (45 in Group A, 10 in Group B) enrolled. In Group A, the 3-month CNS progression-free survival was 27%, the median overall survival was 12.7 months, and the overall response rate was 9%. In Group B, which enrolled 5 patients with leptomeningeal disease and 5 with no prior WBRT, no responses occurred and 8 patients had CNS progression before 3 months. Systemic responses occurred in 15% of patients, including a complete response in liver metastases. Diarrhea occurred in 87% of patients; 25% had grade 3 and 4 adverse events. CONCLUSIONS Patupilone in patients with BCBM did not meet the efficacy criteria and had significant gastrointestinal toxicity. Further study of brain-penetrant agents is warranted for patients with CNS metastases from breast cancer.

Serum N-Telopeptide and Bone-Specific Alkaline Phosphatase Levels in Patients With Osteonecrosis of the Jaw Receiving Bisphosphonates for Bone Metastases

PURPOSE Oversuppression of bone turnover can be a critical factor in the pathogenesis of osteonecrosis of the jaw (ONJ). We investigated N-telopeptide of type I collagen (NTX) and bone-specific alkaline phosphatase (BAP) as potential predictors of ONJ onset. PATIENTS AND METHODS Patients with ONJ and available stored serum were identified retrospectively from the institutional databases. Four approximate points were examined: point of ONJ diagnosis and 12, 6, and 1 month before the diagnosis. NTX and BAP were measured using enzyme-linked immunosorbent assays and examined as possible predictors of ONJ. RESULTS From March 1998 to September 2009, we identified 122 patients with ONJ. Of these, 56 (46%) had one or more serum samples available. Overall, 55 patients (98%) received bisphosphonates. Using the exact dates, no obvious patterns in either NTX or BAP were noted. Similarly, using the ordinal points, no evidence of suppression of NTX or BAP over time was seen. The consecutive median values were as follows: The median NTX values were 8.0 nmol/L (range 3.8 to 32.9) at 12 months before ONJ; 9.5 nmol/L (range 4.7 to 42.7) at 6 months; 9.5 nmol/L (range 4.5 to 24.6) at 1 month, and 10.4 nmol/L (range 4.4 to 32.5) at the ONJ diagnosis. The median BAP values were BAP 18.0 U/L (range 7.0 to 74) at 12 months before ONJ; 18.0 U/L (range 4.0 to 134) at 6 months; 14.0 U/L (range 4.0 to 132) at 1 month, and 18.0 U/L (range 0.7 to 375) at the ONJ diagnosis. Only 2 patients (4%) had NTX and 17 (30%) had BAP below the normal range at the ONJ diagnosis. CONCLUSIONS In the present large retrospective study, no trends were seen in the NTX and BAP levels before the ONJ diagnosis.

Tucatinib with capecitabine and trastuzumab in advanced HER2-positive metastatic breast cancer with and without brain metastases: a non-randomised, open-label, phase 1b study

BACKGROUND Tucatinib is a potent and selective oral HER2 tyrosine kinase inhibitor, with the potential to provide a well tolerated new treatment option for patients whose disease has progressed on currently available therapies. We aimed to determine the recommended phase 2 dose, safety, pharmacokinetics, and preliminary activity of tucatinib in combination with capecitabine or trastuzumab in patients with HER2-positive breast cancer with or without brain metastases. METHODS In this non-randomised, open-label, phase 1b trial done in five sites in the USA, we recruited patients aged 18 years or older with HER2-positive progressive breast cancer who had been previously treated with trastuzumab, pertuzumab, and trastuzumab emtansine. Eligible patients required HER2-positivity assessed locally, evaluable lesions as defined per Response Evaluation Criteria in Solid Tumors, version 1.1, and an Eastern Cooperative Oncology Group performance status of 0 or 1. Tucatinib was administered twice a day in conjunction with capecitabine 1000 mg/m2 orally twice a day for 14 days of a 21-day cycle, trastuzumab 6 mg/kg intravenously once every 21 days, or both. A modified 3 + 3 dose-escalation design was used to determine the recommended phase 2 dose, starting with tucatinib in combination with capecitabine or trastuzumab, and subsequently evaluating the triplet combination. The primary endpoint was to establish the maximum tolerated dose and recommended phase 2 dose of tucatinib, evaluated by toxicity assessments. Efficacy was assessed in all patients by contrast CT of the body. Analyses included all patients who had received at least one dose of study treatment. The study is registered with ClinicalTrials.gov, number NCT02025192. FINDINGS Between Jan 15, 2014, and Dec 15, 2015, 60 patients were enrolled and treated. The current report is from mature data as of June 30, 2017. The tucatinib recommended phase 2 dose was determined to be 300 mg orally twice a day, equivalent to single-agent maximum tolerated dose. Pharmacokinetic analysis showed that there was no drug-drug interaction with capecitabine. Adverse events seen at the recommended phase 2 dose regardless of causality, grade, and treatment group included diarrhoea (35 [67%] of 52 patients), nausea (31 [60%] patients), palmar-plantar erythrodysaesthesia syndrome (23 [44%] patients), fatigue (20 [38%] patients), and vomiting (20 [38%] patients). In all patients, treatment-related toxicities of grade 3 and worse included fatigue (five [8%] patients), diarrhoea (four [7%] patients), and palmar-plantar erythrodysaesthesia (four [7%] patients). No treatment-related deaths were reported. The proportion of patients with measurable disease achieving objective response was 83% (five of six patients) in the combination of tucatinib with capecitabine, 40% (six of 15 patients) in the combination of tucatinib with trastuzumab, and 61% (14 of 23 patients) in the combination of tucatinib with both capecitabine and trastuzumab. INTERPRETATION Tucatinib in combination with capecitabine and trastuzumab had acceptable toxicity and showed preliminary anti-tumour activity. Validation of the current study results will be determined in the double-blinded randomised study, HER2CLIMB (ONT-380-206; NCT02614794). FUNDING Cascadian Therapeutics, a wholly owned subsidiary of Seattle Genetics.