GlaxoSmithKline (GSK) plc announced that its study of Tykerb/Tyverb (lapatinib) in combination with chemotherapy in patients with HER2-positive advanced gastric cancer did not meet the primary endpoint of improved overall survival (OS) compared to chemotherapy alone. The median OS for patients in the lapatinib plus chemotherapy group was 12.2 months compared to 10.5 months for patients randomised to placebo plus chemotherapy (HR=0.91; 95% CI: 0.73, 1.12; p=0.3492). There were no new safety signals identified in this trial.

This was a randomised, double-blinded phase III study of lapatinib in combination with chemotherapy (oxaliplatin and capecitabine) compared to chemotherapy plus placebo in patients with HER2-positive advanced gastric cancer in the first line treatment setting. The primary endpoint was overall survival and secondary endpoints included progression-free survival, response rate and duration of response. Median progression-free survival for patients in the lapatinib plus chemotherapy group was 6.0 months and 5.4 months for those in the chemotherapy alone group. Response rate was 53% for patients in the lapatinib plus chemotherapy group and 39% for those in the chemotherapy alone group.  In the lapatinib plus chemotherapy group, the duration of response was 7.3 months compared to 5.6 months in the placebo plus chemotherapy group.

The most commonly reported (= 20%) adverse events (AE) in the lapatinib plus chemotherapy group were diarrhoea (58%), nausea (49%), vomiting (44%), decreased appetite (41%), fatigue (24%), rash (21%) and palmar-plantar erythrodysesthesia (20%). The most common AEs in the chemotherapy alone group were nausea (43%), vomiting (36%), decreased appetite (32%), diarrhoea (29%), fatigue (21%) and peripheral neuropathy (20%).  Serious adverse events (SAEs) reported in more than 2% of patients in the lapatinib plus chemotherapy group were diarrhoea (6%), vomiting (3%), anaemia (2%), dehydration (2%), nausea (2%). Vomiting (2%) was the most common SAE reported in the chemotherapy group.

Tykerb/Tyverb (lapatinib) is not approved or licensed anywhere in the world for the treatment of HER2-positive advanced gastric cancer.

This was a  global, randomised, multicentre, double-blinded, phase III study comparing the efficacy and tolerability of lapatinib in combination with oxaliplatin and capecitabine to oxaliplatin, capecitabine and placebo in subjects with HER2-positive advanced gastric (including esophageal and gastro-esophageal junction) cancer in the first line  treatment setting.  GSK collaborated with the TRIO/IDDI (Translational Research in Oncology, TRIO; International Drug Development Institute) cooperative research group to conduct the study. The primary end point of overall survival (OS) was evaluated in the primary efficacy population which was defined as those randomised patients with HER2-positive tumours confirmed by fluorescence in situ hybridisation (FISH) testing conducted by a central laboratory. Secondary endpoints included progression-free survival, response rate, safety and quality of life.