Immuneering (IMRX) Study Update summary

Study background and design

• IMM-1-104 is a uniquely designed MEK inhibitor targeting the MAP kinase pathway, aiming to improve outcomes for patients with RAF or RAS-driven tumors, particularly pancreatic cancer.

• The Phase II-A/2a study evaluates IMM-1-104 alone and in combination with modified gemcitabine and nab-paclitaxel across multiple arms, including three for pancreatic cancer and others for RAS mutant melanoma and non-small cell lung cancer, with 30 patients per arm.

• The combination arm uses a less intensive, better-tolerated chemotherapy regimen administered every other week.

• IMM-1-104 received FDA Fast Track designation for first- and second-line pancreatic cancer.

• Enrollment is progressing well, with further data from additional arms expected by year end.

Initial efficacy results

• Among the first five evaluable patients, one achieved a complete response at the first scan, sustained over four scans and more than six months, and a second patient showed a deepening partial response with lesions shrinking by 40% at the third scan.

• The initial overall response rate is 40%, and the disease control rate is 80%, both exceeding historical benchmarks for chemotherapy alone.

• All five patients remain on treatment, with the remaining three having stable disease or equivocal progressive disease.

• CA19-9 tumor marker reductions were observed in two patients, supporting evidence of tumor response.

• Preclinical data suggested synergy between IMM-1-104 and chemotherapy, leading to deeper responses than either agent alone.

Safety and tolerability

• The combination of IMM-1-104 with modified gemcitabine and nab-paclitaxel has been well-tolerated, consistent with the safety profiles of each agent alone.

• No unexpected safety signals or significant adverse events have been reported at the 240 mg dose.

• The Data and Safety Monitoring Board has approved escalation to a 320 mg dose, with both doses showing activity and additional patients dosed at this level.

• Deep Cyclic Inhibition profiles are robust at both 240 mg and 320 mg, with a slight edge at the higher dose.

• Safety and efficacy at the higher dose will be further evaluated as more patients are treated.