title: Continuation of trastuzumab beyond disease progression in HER2-positive metastatic gastric cancer: the MD Anderson experience.
abstract: BACKGROUND
  Despite the wide spread use of trastuzumab in human epidermal growth factor receptor 2 (HER2) overexpressing metastatic gastric cancer patients, its optimal duration of administration beyond first-line disease progression is unknown. In HER2 overexpressing metastatic breast cancer, trastuzumab continuation beyond first-line disease progression has shown improvement in time to progression (TTP) without an increased risk of treatment related toxicity.
  
  
  METHODS
  HER2-overexpressing metastatic gastric cancer patients were identified from our database between January 2010 and December 2014. We retrospectively reviewed the medical records of 43 patients who received trastuzumab in combination with chemotherapy as first-line and continued trastuzumab beyond disease progression.
  
  
  RESULTS
  Forty-three cases were identified, 27 males (62.8%), median age of the patients was 58 years. Thirty-five (81.4%) presented with stage 4 as their initial presentation. Eighty one percent had 3+ HER2 overexpression by immunohistochemistry (IHC) and 18% had 2+ HER2 overexpression confirmed by fluorescence in situ hybridization (FISH). Thirteen (52%) were moderately differentiated, 16 (37.1%) were poorly differentiated. The most common sites of metastasis were liver 35 (81.4%) and lung 14 (32.5%). The most commonly used first-line regimen was oxaliplatin, 5-fluorouracil (5-FU), and trastuzumab in 22 (51.1%) patients. Twenty-five (58.1%) patients received irinotecan, 5-FU and trastuzumab in the second-line. Progression-free survival (PFS) was 5 months (95% CI: 4.01-5.99 months). Five patients are still alive and excluded from calculating the median overall survival (OS) which was 11 months (range, 5-53 months) for the remaining 20 subjects of this second-line group. Trastuzumab was not discontinued due to side effects in any of the study population.
  
  
  CONCLUSIONS
  In conclusion, this retrospective analysis suggests that continuation of trastuzumab beyond disease progression in patients with HER2-overexpressing metastatic gastric cancer is feasible and safe. Randomized studies are warranted.
authors: Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Humaid O
authors: HO
authors: Al-Shamsi
authors: Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Yazan
authors: Y
authors: Fahmawi
authors: Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Ibrahim
authors: I
authors: Dahbour
authors: Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Aziz
authors: A
authors: Tabash
authors: Pharmacy Clinical Programs, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Jane E
authors: JE
authors: Rogers
authors: Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Jeannette Elizabeth
authors: JE
authors: Mares
authors: Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Mariela A
authors: MA
authors: Blum
authors: Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Jeannelyn
authors: J
authors: Estrella
authors: Department of Diagnostic Radiology, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Aurelio
authors: A
authors: Matamoros
authors: Department of Diagnostic Radiology, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Tara
authors: T
authors: Sagebiel
authors: Department of Diagnostic Radiology, Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Catherine E
authors: CE
authors: Devine
authors: Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Brian D
authors: BD
authors: Badgwell
authors: Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Quan D
authors: QD
authors: Lin
authors: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Prajnan
authors: P
authors: Das
authors: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors: Jaffer A
authors: JA
authors: Ajani
keywords: Gastric cancer; human epidermal growth factor receptor 2 (HER2); trastuzumab