A Clear Look at the Science Driving Our Work

Inside each cell is a network of signaling pathways that help the body function smoothly. One of the most important of these networks is called the MAPK pathway. It helps cells understand when to grow, repair themselves, or rest. Under healthy conditions, this pathway turns on and off at the right times, similar to a well-regulated traffic system.

In some cancers, however, certain genes become altered in a way that keeps the MAPK pathway switched on. When this happens, the pathway sends a constant message for cells to grow and divide even when growth is not needed. Over time, this can contribute to the formation and spread of tumors. This type of overactive signaling is especially common in difficult-to-treat cancers such as pancreatic cancer, certain lung cancers, colorectal cancer, melanoma and thyroid cancers.

MEK is one of the key signaling proteins in the MAPK pathway. It plays a central role in passing signals from one step of the pathway to the next, helping regulate how quickly cells grow and multiply. When MEK becomes overactive, the instructions it sends can become too strong or too frequent, allowing cancer cells to grow and divide more rapidly.

Because of this, MEK has been a focus of cancer research for many years. However, traditional MEK inhibitors can sometimes be difficult for patients to tolerate, and some may not remain effective over long periods of time. These challenges have motivated the search for new approaches that may offer stronger, more sustainable activity with fewer side effects. Immuneering’s Deep Cyclic Inhibitors were created with this need in mind.

Immuneering’s platform was designed to take a different approach to MEK inhibition. Instead of blocking MEK continuously, our Deep Cyclic Inhibitors are engineered to deliver strong inhibition for a period of time followed by a short recovery window that allows healthy systems in the body to reset. This creates a cycle of inhibition and recovery that repeats daily.

This approach is rooted in a simple idea: cancer treatments need to maintain their effectiveness, but they also need to be tolerable enough for patients to remain on therapy. By giving the body time to recover between periods of intense MEK inhibition, our Deep Cyclic Inhibitors are designed with the potential for more durable anti-tumor activity and fewer treatment-related side effects. For patients, this may translate into better long-term tolerability, more consistent daily functioning, and an overall improved quality of life while receiving treatment. Our Deep Cyclic Inhibitors remain investigational, and ongoing research aims to understand how this approach behaves in the body and which cancers may benefit most from this strategy.

Atebimetinib is Immuneering’s first investigational medicine created using Deep Cyclic Inhibition. It is a once-daily pill being studied as a way to target the MAPK pathway in cancers, such as pancreatic and non-small cell lung cancer, with the goal of providing strong and sustained tumor control while remaining easier for patients to tolerate.

In a Phase 2a clinical trial in frontline pancreatic cancer, atebimetinib showed extraordinary signals of activity for this disease, including encouraging trends in how long patients lived and how long their cancer remained stable before progressing. Patients also reported that the treatment was generally well tolerated, with many experiencing fewer or milder side effects. For individuals living with cancer, tolerability can play a meaningful role in maintaining daily routines, comfort, and overall quality of life. A Phase 3 trial is planned to begin dosing in mid-2026 to evaluate this benefit in a larger group of patients.

Because alterations in the MAPK pathway are found in multiple cancers, Immuneering is studying its Deep Cyclic Inhibitors such as atebimetinib in tumor types where this pathway plays a significant role. Pancreatic cancer is a key initial focus, and work is also underway to evaluate atebimetinib in non-small cell lung cancer and to explore opportunities for additional MAPK-driven cancers. Research in this area continues to grow as scientists learn more about how Deep Cyclic Inhibition behaves across different tumor types.