Abstract 1032P
Background
Stratum D of the INSIGHT platform trial evaluates s.c. application of IMP321 combined with avelumab in advanced stage solid tumors. The MHC class II agonist IMP321 activates antigen-presenting cells followed by CD8 T-cell activation. Combination with PD-1/PD-L1 blockade aims at enhanced therapeutic efficacy.
Methods
The investigator-initiated study consists of 4 strata: intratumoral (A) or intraperitoneal IMP321 (B); s.c. IMP321 with SOC (C) or with PD-L1 inhibition (D). This abstract focuses on preliminary safety data of Stratum D. Patients (pts) receive 800mg avelumab i.v. q2w along with s.c. IMP321: 6mg IMP321 in cohort 1 (6 pts), 30mg IMP321 in cohort 2 (6 pts). Primary endpoint is safety.
Results
12 pts have been recruited displaying different solid tumor types (cohort 1: gastric, gallbladder, colon cancer, pleural mesothelioma; cohort 2: gastric, gastroesophageal, anal, rectum, cervical cancer). So far, no dose limiting toxicities (DLTs) occurred. 6 serious adverse events (SAEs) were reported, none of them considered causally related (3 SAEs in 2 pts of cohort 1 [1 acute kidney injury grade 5 in 1 pt, 2 preileus grade 3 in 1 pt] and 3 SAEs in 2 pts of cohort 2 [1 anal hemorrhage, 1 gallbladder obstruction, 1 eye pain, each grade 3]. In cohort 1, 43 adverse events (AEs; grade 1-2, 26; grade 3, 15; grade 4, 1; grade 5, 1) occurred in 5 pts. Most common grade 1-2 AEs were pain, nausea, agitation, injection site reaction in 50%, 33%, 17%, 17% of the pts. Most common grade 3 AEs were preileus/ileus, nausea/vomiting, ascites in 33%, 33%, 17% of the pts. 1 AE grade 4 (sepsis) and 1 AE grade 5 (acute kidney injury) were reported. All AEs grade 3-5 were considered causally unrelated. 1 AE of special interest (AESI) possibly related with avelumab (sarcoidosis grade 1) occurred. So far, 4 pts showed partial response, 3 disease progression acc. to RECIST 1.1, 2 clinical progression, 3 have not had tumor assessment yet.
Conclusions
Combination treatment with avelumab 800mg and IMP321 6mg (cohort 1) is feasible and safe. So far, 30 mg IMP321 in cohort 2 appears to be feasible and safe, as well (data will be presented at the meeting).
Clinical trial identification
NCT03252938; EudraCT: 2016-002309-20.
Editorial acknowledgement
Legal entity responsible for the study
Institut für Klinische Krebsforschung IKF GmbH am Krankenhaus Nordwest.
Funding
Immutep GmbH.
Disclosure
S-E. Al-Batran: Research grant/Funding (institution): Immutep. All other authors have declared no conflicts of interest.