Efficacy and safety profile of nab-paclitaxel plus gemcitabine in patients with metastatic pancreatic cancer treated to disease progression: a subanalysis from a phase 3 trial (MPACT).

BACKGROUND: The phase 3 MPACT trial in patients with metastatic pancreatic cancer demonstrated superior efficacy of nab-paclitaxel (nab-P) + gemcitabine (Gem) vs Gem monotherapy for all endpoints examined including overall survival, the primary endpoint. In the MPACT trial, patients were treated until progressive disease (PD) or unacceptable toxicity. The current exploratory analysis investigated outcomes of patients from the MPACT trial who were treated until PD, in order to understand how to maximize treatment benefit from nab-P + Gem. METHODS: The trial design has been described in detail previously. Progressive disease was determined by the investigator on the basis of radiological imaging. RESULTS: Among patients who were treated until PD, overall survival was significantly longer for those who received nab-P + Gem vs Gem (median, 9.8 vs 7.5 months; P < 0.001). Independently assessed progression-free survival and overall response rate were significantly greater among patients in the treatment-to-PD cohort who received nab-P + Gem compared with Gem (P < 0.001 for each). Although not compared statistically, patients who were treated until PD received greater treatment exposure and experienced more favourable efficacy than the intent-to-treat population of the MPACT trial. Among patients who were treated with nab-P + Gem until PD, > 50 % went on to receive a subsequent therapy. The safety profile for patients treated until PD was similar to what was reported in the overall MPACT trial. CONCLUSION: The nab-P + Gem regimen is an active first-line treatment option; most patients were treated until PD, and this exposure was associated with improved efficacy outcomes. Prolonged first-line treatment exposure and ability to receive subsequent therapies likely contributed to the improved survival among these patients. Our data highlight the importance of managing adverse events and indicate that patients should be treated until PD when possible. TRIAL REGISTRATION: ClinicalTrials.gov NCT00844649 (MPACT trial); Registration date of this prospective phase III trial: February 13, 2009; current exploratory subanalysis was conducted retrospectively.

Nomogram for Estimating Overall Survival in Patients With Metastatic Pancreatic Cancer.

OBJECTIVES: This analysis investigated nomogram use to evaluate metastatic pancreatic cancer prognosis. METHODS: Thirty-four baseline factors were examined in the Metastatic Pancreatic Adenocarcinoma Clinical Trial (MPACT) (nab-paclitaxel plus gemcitabine vs gemcitabine) data set. Factors significantly (P < 0.1) associated with overall survival (OS) in a univariable model or with known clinical relevance were tested further. In a multivariable model, factors associated with OS (P < 0.1) were selected to generate the primary nomogram, which was internally validated using bootstrapping, a concordance index, and calibration plots. RESULTS: Using data from 861 patients, 6 factors were retained (multivariable analysis): neutrophil-lymphocyte ratio, albumin level, Karnofsky performance status, sum of longest diameter of target lesions, presence of liver metastases, and previous Whipple procedure. The nomogram distinguished low-, medium-, and high-risk groups (concordance index, 0.67; 95% confidence interval, 0.65-0.69; median OS, 11.7, 8.0, and 3.3 months, respectively). CONCLUSIONS: This nomogram may guide estimates of the range of OS outcomes and contribute to patient stratification in future prospective metastatic pancreatic cancer trials; however, external validation is required to improve estimate reliability and applicability to a general patient population. Caution should be exercised in interpreting these results for treatment decisions: patient characteristics could differ from those included in the nomogram development.

First-Line Doublet Chemotherapy for Metastatic Triple-Negative Breast Cancer: Circulating Tumor Cell Analysis of the tnAcity Trial.

PURPOSE: Circulating tumor cells (CTCs) are prognostic biomarkers in metastatic breast cancer, but their role in predicting treatment outcomes in metastatic triple-negative breast cancer (mTNBC) is less clear. The tnAcity trial demonstrated a significant progression-free survival (PFS) benefit with nab-paclitaxel (nab-P)/carboplatin (C) over nab-P/gemcitabine (G) or G/C in patients with mTNBC. We assessed the correlation between CTC dynamics and clinical benefit in all patients and by treatment arm. METHODS: CTC enumeration, performed using CELLSEARCH technology (Menarini Silicon Biosystems, Huntingdon Valley, PA, USA), was a prespecified exploratory endpoint in the tnAcity trial. Patients with TNBC were categorized based on pre- and post-treatment CTC levels: Group 1 (+ + +; elevated CTCs at baseline and postbaseline), Group 2 (+ ± ±; CTCs elevated at baseline and cleared postbaseline [cycle 3 and/or cycle 5]), or Group 3 (-; no CTCs detected at baseline). The baseline cutoff was ≥1 CTC/7.5 mL for the main analysis; cutoffs of ≥2 and ≥5 CTCs were used for supporting analyses. RESULTS: The main analysis included 126 patients (Group 1, n = 24; Group 2, n = 54; and Group 3, n = 48). The median PFS was longer in Group 2 vs Group 1 (8.5 vs 4.7 months; HR, 0.30 [95% CI, 0.17-0.54]). These results were supported by the ≥2- and ≥5-CTC cutoff analyses. The median overall survival rates were 17.8, 16.0, and 9.8 months in Groups 2, 3, and 1, respectively. The overall response rates were 79.6%, 43.8%, and 29.2%, respectively. A numerically higher percentage of patients had CTC clearance during nab-P/C treatment vs nab-P/G or G/C. CONCLUSION: Efficacy outcomes trended positively with chemotherapy-induced elimination of CTCs, suggesting that CTC clearance may predict the chemosensitivity of mTNBC tumors. TRIAL REGISTRATION: EudraCT Number: 2013-000113-20; ClinicalTrials.gov number: NCT01881230.

18F-FDG PET/CT response in a phase 1/2 trial of nab-paclitaxel plus gemcitabine for advanced pancreatic cancer.

BACKGROUND: Positron emission tomography (PET) is poised to become a useful imaging modality in staging and evaluating therapeutic responses in patients with metastatic pancreatic cancer (mPC). This analysis from a phase 1/2 study examined the utility of early PET imaging in patients with mPC treated with nab-paclitaxel plus gemcitabine. METHODS: Tumors were measured by [18F]2-fluoro-2-deoxyglucose PET/computed tomography (CT) in patients who received nab-paclitaxel 100 (n = 13), 125 (n = 38), or 150 (n = 1) mg/m2 plus gemcitabine 1000 mg/m2 on days 1, 8, and 15 of a 28-day cycle. Lesion metabolic activity was evaluated at baseline and 6 and 12 weeks postbaseline. RESULTS: Fifty-two patients had baseline and ≥1 follow-up PET scan. The median maximum standardized uptake values per pancreatic lesion in the nab-paclitaxel 100 mg/m2 and 125 mg/m2 cohorts were 5.1 and 6.5, respectively. Among patients who had a metabolic response by PET, those who received nab-paclitaxel 125 mg/m2 had a 4-month survival advantage over those who received 100 mg/m2. All patients in the nab-paclitaxel 125 mg/m2 cohort experienced an early complete metabolic response (CMR; 34%) or partial metabolic response (PMR; 66%). In the nab-paclitaxel 125 mg/m2 cohort, investigator-assessed objective response rates were 77% and 44% among patients with a CMR and PMR, respectively, with no correlation between PET and CT response (Spearman r s = 0.22; P = 0.193). Patients in the nab-paclitaxel 125 mg/m2 cohort with a CMR experienced a significantly longer overall survival vs those with a PMR (median, 23.0 vs 11.2 months; P = 0.011), and a significant correlation was found between best percentage change in tumor burden by PET and survival: for each 1% decrease in PET score, the risk of death decreased by 2%. CONCLUSIONS: The majority of primary pancreatic tumors and their metastases were PET avid, and PET effectively measured changes in tumor metabolic activity at 6 and 12 weeks. These results support the antitumor activity of nab-paclitaxel 125 mg/m2 plus gemcitabine 1000 mg/m2 for treating mPC and the utility of PET for measuring treatment response. Treatment response by PET analysis may be considered when evaluating investigational agents in mPC. TRIAL REGISTRATION: NCT00398086.

Dose modification and efficacy of nab-paclitaxel plus gemcitabine vs. gemcitabine for patients with metastatic pancreatic cancer: phase III MPACT trial.

BACKGROUND: Dose modifications following adverse events (AEs) are an important part of the management of patients with pancreatic cancer treated with chemotherapy. While dose modifications are utilized to ensure patient safety, the subsequent influence of dose adjustments on treatment exposure and efficacy have not been reported in detail. This exploratory analysis examined the influence of dose modifications on treatment exposure and efficacy in the phase III MPACT trial, which demonstrated superior efficacy of nab-paclitaxel (nab-P) plus gemcitabine (Gem) to Gem alone for the treatment of metastatic pancreatic cancer. METHODS: Patients received either nab-P 125 mg/m(2) + Gem 1,000 mg/m(2) on days 1, 8, and 15 every 4 weeks or Gem 1,000 mg/m(2) weekly for the first 7 of 8 weeks (cycle 1) and then days 1, 8, and 15 every 4 weeks (cycle ≥2). The protocol allowed up to 2 dose reductions per agent. Dose delays were also used to manage toxicities. RESULTS: Toxicities that most commonly led to dose modifications were neutropenia, peripheral neuropathy, thrombocytopenia, and fatigue for nab-P and neutropenia, thrombocytopenia, and fatigue for Gem alone. Baseline characteristics were similar in patients with dose modifications and the intent-to-treat (ITT) population. Among the 421 treated patients in the nab-P + Gem arm, all patients initiated treatment at the per-protocol nab-P starting dose of 125 mg/m(2); 172 (41%) had a nab-P dose reduction, and 300 (71%) had a nab-P dose delay during the study. Most dose modifications occurred after the first 3 months (2 cycles) of treatment. The majority of patients (104/172, 60%) required only 1 nab-P dose reduction, and over half of patients (163/300) had either 1 or 2 dose delays. Patients who underwent dose modifications of nab-P had greater treatment exposure than those who did not in terms of treatment duration, number of cycles administered, and cumulative dose of nab-P delivered. Overall survival (OS) was shorter in the nab-P + Gem arm for patients who did not vs. did undergo dose reduction [median, 6.9 vs. 11.4 months; hazard ratio (HR), 1.93; 95% CI, 1.53-2.44; P<0.0001] and for those who did not vs. did undergo a dose delay (median, 6.2 vs. 10.1, HR, 2.05; 95% CI, 1.60-2.63; P<0.0001). Progression-free survival (PFS) and overall response rate (ORR) were also improved in patients with dose modifications. Similar trends were observed in the Gem-alone arm. Multivariate analyses confirmed that both dose delay and dose reduction were significantly associated with OS. CONCLUSIONS: This analysis suggests that although most doses of nab-P were given at the starting dose of 125 mg/m(2) the first 3 of 4 weeks, dose reductions and delays were effective when necessary to ameliorate toxicity allowing greater treatment exposure without compromising efficacy.