Ganymed Pharmaceuticals AG, a biopharmaceutical company developing highly targeted immunotherapies against cancer, announced outstanding data from its randomized phase II clinical study of IMAB362 in first-line treatment of gastric cancer at the ASCO 2016 Annual Meeting.
IMAB362 is a first-in-class monoclonal antibody targeting the cell surface molecule Claudin18.2. The phase II study in patients with advanced biomarker-positive gastric cancer reached all its endpoints. As a key finding, IMAB362 significantly extended median overall survival when added to standard chemotherapy (13.2 months vs. 8.4 months, HR 0.51, p=0.0001). Patients with the highest levels of Claudin18.2 had an even longer median overall survival (16.7 months vs 9.0 months, HR 0.45, p<0.0005). IMAB362 was well tolerated during the study; most frequent adverse effects were vomiting, nausea and neutropenia.
“Patients diagnosed with advanced gastric cancer currently have a poor prognosis and few available therapeutic options. Results of our study clearly show clinically meaningful efficacy for patients and a favorable risk/benefit profile in this indication of high medical need,” said Dr. Salah-Eddin Al-Batran, a medical oncologist and Director at the Institute of Clinical Cancer Research, Nordwest Hospital in Frankfurt, who presented the data at the ASCO.
“This antibody combines high precision targeting of Claudin18.2 positive tumors with strong immunooncological modes of action,” said Dr. Özlem Türeci, co-founder and CEO of Ganymed. “We are very excited to see that patients in our study benefited very significantly from being treated with IMAB362 with more than twice the number of patients still living at the end of the study after receiving IMAB362 plus chemotherapy compared to chemotherapy alone.”
The study included 161 patients with advanced or recurrent gastric or gastroesophageal junction cancer with a specific minimal level of Claudin18.2 in the tumor. Claudin18.2 levels were assessed from tumor biopsy specimen using the validated CE-marked diagnostic assay Claudetect18.2.
Patients were then randomly assigned to receive standard chemotherapy (epirubicin, oxaliplatin and capecitabine) with IMAB362 (800/600 mg/m2) or chemotherapy alone. Moreover, an additional 85 patients were treated in an added exploratory arm with a higher IMAB362 dose.
Compared to chemotherapy alone, IMAB362 extended the median time to disease progression from 4.8 to 7.9 months (HR 0.47, p=0.0001) and the median overall survival from 8.4 to 13.2 months (HR 0.51, p=0.0001). Among the patients with the highest levels of Claudin18.2, the median overall survival was 16.7 months with IMAB362 and 9 months with chemotherapy alone (HR 0.45, p<0.0005).
Treatment with IMAB362 was well tolerated during the study. Vomiting (34.5% of patients with grade 1/2 and 3.6% with grade 3/4 in the control arm versus 55.8% of patients with grade 1/2 and in 10.4% with grade 3/4 in the IMAB362 arm) and low blood counts (neutropenia; 21.4% of patients with grade 1/2 and 21.4 % with grade 3/4 in the control arm versus 23.4% of patients with grade 1/2 and in 32.5% with grade 3/4 in the IMAB362 arm) were slightly more common in the IMAB362 group. The rates of severe adverse effects were not increased with IMAB362 compared to chemotherapy alone.
IMAB362 is a first-in-class immunotherapeutic investigational drug that is selective and specific for the tight junction protein Claudin18.2. This unique target is restricted to differentiated stomach cells only and is absent from all other healthy tissues. Claudin18.2 is upregulated in various cancers including in about 80% of gastrointestinal adenocarcinomas, 60% pancreatic tumors as well as in biliary, ovarian and lung cancers. Hence, IMAB362 is of interest for various high medical need cancers, in which this unique target is expressed.
IMAB362 has received orphan drug designation in the US and Europe for gastric and pancreatic cancer. Its mechanism of action includes activation of antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC) and – in combination with chemotherapy – T-cell infiltration and modulation of the tumor microenvironment. IMAB362 showed single agent anticancer activity in previous clinical studies in heavily pretreated patients with Claudin18.2-positive gastroesophageal cancer.