Modified GEMZAR® and ABRAXANE® Combination May Preserve Efficacy with Less Toxicity in Metastatic Pancreatic Cancer

SUMMARY: The American Cancer Society estimates that in 2015, close to 49,000 people will be diagnosed with pancreatic cancer in the United States and over 40,000 people will die of the disease. Some important risk factors for pancreatic cancer include increasing age, obesity, smoking history, genetic predisposition, exposure to certain dyes and chemicals, heavy alcohol use and pancreatitis. The best chance for long term survival is complete surgical resection, although this may not be feasible in a majority of the patients, as they present with advanced disease at the time of diagnosis. Based on the National Cancer Data Base, the 5 year observed survival rate for patients diagnosed with exocrine cancer of the pancreas is 14% for those with Stage IA disease and 1% for those with Stage IV disease. The benefit of a combination of GEMZAR® (Gemcitabine) and ABRAXANE® (nab-Paclitaxel regimen in first line treatment for metastatic pancreatic cancer was established following a open-label, randomized, phase III trial (MPACT trial) in which 861 patients with metastatic pancreatic cancer were randomized to receive either a combination of GEMZAR® and ABRAXANE® (n=431) or GEMZAR® alone (n=430). The treatment regimen consisted of GEMZAR® at 1000 mg/m2 IV and ABRAXANE® 125 mg/m2 IV, both administered on days 1, 8, and 15 of a 28 day cycle. There was a statistically significant prolongation of Overall Survival (OS) for patients in the combination group with a 28% reduction in the risk of death [HR= 0.72; P < 0.0001]. The median OS was 8.5 months in the combination group and 6.7 months in the single agent GEMZAR® group and the Progression Free Survival (PFS) in the combination group versus the single agent group was 5.5 months versus 3.7 months, respectively (HR= 0.69; P < 0.0001). In this study however, only 71% of the ABRAXANE® doses and 63% of the GEMZAR® doses were full doses, due to associated toxicities and 17% of the patients had grade 3 or 4 neuropathy.

To circumvent this toxicity, the authors at their institution adopted a modified regimen of GEMZAR® and ABRAXANE® for a similar patient population and the regimen consisted of GEMZAR® 1000 mg/m2 IV and ABRAXANE® 125 mg/m2 IV, both administered on days 1 and 15 of a 28 day cycle. They conducted a retrospective analysis of a prospectively maintained database of 69 patients treated with this modified regimen. A total of 47 patients were evaluable for responses and 63 patients were evaluable for toxicities. The median Progression Free Survival was 4.8 months and median Overall Survival was 11.1 months with the modified regimen. More importantly, the rate of grade 3 or 4 neuropathy was less than 2%. The rate of grade 3 or 4 neutropenia was 10%, and growth factor support was required in only 8% of the patients, compared with 26% for those in the MPACT trial. The authors concluded that a less intense biweekly regimen of GEMZAR® and ABRAXANE® preserves efficacy with significantly less toxicity as well as cost savings and should be a consideration, in the first line treatment of patients with metastatic pancreatic cancer. This study received a Merit Award at the 2015 Gastrointestinal Cancers Symposium. Modified gemcitabine and nab-paclitaxel in patients with metastatic pancreatic cancer (MPC): A single-institution experience. Krishna K, Blazer MA, Wei L, et al. J Clin Oncol 33, 2015 (suppl 3; abstr 366)