ASCO 2026: GLP-1 Receptor Agonists May Reduce Mortality in Patients With Cancer

In this interview with Pharmacy Times at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, Jessica Paulus, ScD, vice president, real-world research, Ontada, discusses new research showing a 34% reduction in mortality among patients with 6 cancer types—including breast, prostate, colorectal, hepatocellular, and renal cell carcinoma—who received glucagon-like peptide-1 (GLP-1) receptor agonists. Paulus explains that although the epidemiologic study was not designed to determine causation, potential mechanisms may include reduced inflammation, improved glycemic control, decreased adipose tissue burden, and possible direct effects on cancer cell proliferation.

Pharmacy Times: Your study found improved overall survival among patients with breast and prostate cancer receiving GLP-1 therapies. What mechanisms do you think may be driving these outcomes, and what questions still need to be answered before these findings could influence routine oncology care?

Jessica Paulus, ScD: In our study, we found a 34% reduction in the rate of death among patients with cancer. The study included 6 different cancer types, including breast and prostate cancer, which were the 2 most common. We also looked at several other cancers, including colorectal cancer, hepatocellular cancer, and renal cell carcinoma.

I think it is a bit too early to speculate about the mechanism. The study that we conducted was at an epidemiologic level, so we were not really interrogating how it happened. There is separate preclinical evidence suggesting that GLP-1s could have a number of anticancer effects through their impact on inflammation and glycemic control. Cancer cells need energy to survive, just like all the cells in our body, and that could be one potential mechanism. There are also biologic data suggesting that GLP-1s may have an effect on the proliferation rate of cancer cells.

Here at ASCO, I have had some really interesting conversations with clinicians about our findings. Some have brought to light another potential mechanism: In addition to a possible direct effect, there could also be an indirect effect in that GLP-1s tend to reduce the burden of adipose tissue in the human body, which could allow cancer therapies to be more effective. That is another potential mechanism.

Pharmacy Times: Many patients receiving cancer treatment are also managing obesity, diabetes, or other metabolic conditions. How important is multidisciplinary coordination when initiating GLP-1 therapy, particularly among oncologists, endocrinologists, primary care providers, and oncology pharmacists?

Paulus: I think over the last few decades, there has been a continued evolution within both the clinical and research communities that we need to stop looking at diseases or systems one at a time. Medical school training forces people to pick a specialty for good reason, but I think the interaction between metabolism and cancer is one perfect illustration of how these issues can be viewed in a siloed fashion.

I think our study [data] certainly [suggest] that bringing together cardiovascular and metabolic disease experts with oncology teams in the care and management of patients is potentially even more important than we previously thought, particularly in the context of GLP-1s. At the same time, it is incredibly challenging because these prescriptions are coming from many different places. They may originate in a primary care setting or through endocrinology for indications such as diabetes.

One of the reasons these medications are so prevalent these days is that nontraditional routes of access are expanding rapidly. If you watch the Super Bowl, you see advertisements for direct-to-consumer access to these medications through telehealth platforms. In preparation for this conference, I tried to find data on what proportion of use is occurring through these nontraditional pathways vs traditional in-person physician prescribing, and I was not able to find any data on that, which is interesting.

I think the only way we are going to quickly understand the potential anticancer effects of this class of medications is if we work together quickly. In particular, I am intrigued by some of the telehealth and direct-to-consumer providers because they are collecting data on GLP-1 use tied to payment. They are actually collecting information on timing, dosage, and symptoms, so that could become another rich research repository to help us better understand this question.

Pharmacy Times: Semaglutide accounted for most GLP-1 use in your cohort. As use of these agents expands, what practical considerations should clinicians and pharmacy teams keep in mind regarding tolerability, adherence, supportive care, or potential interactions during active cancer treatment?

Paulus: I think as these medications become so prevalent, this is something all providers are going to need to think about, particularly the interaction of adverse effects. I recently saw an estimate that 1 in 8 Americans are taking these medications or have taken them.

Our research was not able to answer some of the questions you posed to support guidance for clinicians because we did not have the right data. I also think we are still very early in our understanding here. The study I conducted with my colleagues is honestly one of the first large-scale studies I have seen. There have been other studies looking at 1 cancer at a time with smaller sample sizes.

I think it is very clear that the clinical community is very hungry for this information and guidance on what to do. I have also heard from patient advocates on the cancer side asking whether we should be encouraging GLP-1 use for cancer control in addition to its initial indications. I understand where those questions are coming from, but we are not there yet in terms of the research or the evidence.

I think we need to see prospective studies. We also need randomized trials of GLP-1 use in cancer populations to better understand what the true signal is vs what might represent bias.

Pharmacy Times: Looking ahead, what types of prospective studies or clinical end points will be most important to determine whether GLP-1 agents may directly improve cancer outcomes beyond metabolic and weight-related effects?

Paulus: I think to truly understand the potential benefit of this medication, and because of the potential significance in oncology, it is really important that we understand this soon. There are a couple of things that need to happen.

We need to use different databases that contain better information on GLP-1 use. For example, the study we are discussing today was based on oncology electronic health record data. Most GLP-1 use is occurring outside the oncology setting, including in primary care, endocrinology, and direct-to-consumer pathways.

We need to bring together data sets that capture detailed information on GLP-1 use, including start dates, stop dates, dose changes, and similar factors. We also need to integrate those data with the best available oncology data, including start and stop dates of anticancer treatments.

Our study looked at overall survival, which was a good place to start, but I think we also need to evaluate earlier end points. I would love to see research on progression-free survival, for example. In addition to reducing mortality, do these agents potentially slow disease progression?