DCIS Breast Cancer Vaccine Study at UPMC Shows Promising Early Response and Safety Data; Expands to a Second Recruitment Site

At the beginning of 2024, a research team from UPMC Hillman Cancer Center and the University of Pittsburgh launched a phase 1b clinical trial to study a potential vaccine for prevention of invasive breast cancer, specifically targeting stage 0 ductal carcinoma in situ (DCIS).

The vaccine candidate and clinical trial is the product of work conducted over the last several decades by Olivera Finn, PhD, targeting the MUC1 antigen, which her lab discovered. Dr. Finn is the University of Pittsburgh Distinguished Professor of Immunology and Surgery and founding chair of the Department of Immunology. She has been at the University of Pittsburgh since 1991 and has conducted numerous clinical trials around MUC1 vaccines for a number of different cancer types, including lung, pancreatic, and colon cancer. And now breast cancer.

Serving as principal investigator for the study is Emilia Diego, MD, associate professor of surgery; division chief, Breast Division and codirector, UPMC Hillman Cancer Center/UPMC Magee-Womens Hospital Breast Cancer Program.

Also collaborating on the project is Julia Foldi, MD, PhD, assistant professor of medicine. Dr. Foldi is a medical oncologist with a focus on clinical and translational research on breast cancer.

The vaccine trial was initially funded through a $100,000 grant from the Pittsburgh-based Glimmer of Hope Foundation. This in turn allowed the team to secure a $2.1 million grant from the Breast Cancer Research Foundation, the largest funder of breast cancer research worldwide, to conduct and recently expand the trial.

“DCIS is an early, noninvasive form of breast cancer with a variable natural history. Not all cases will progress, but we do not yet have a reliable way to distinguish which lesions will become invasive, so the standard approach remains surgical management. As a result, some patients are treated surgically for disease that may never have become invasive. At the same time, when patients hear the word ‘cancer,’ the instinct is to move forward with surgery immediately. So, you are balancing uncertainty in the biology with a very real urgency to treat,” Dr. Diego says.

Trial Details and Study Aims

This early-phase clinical trial is evaluating a vaccine-based treatment approach in women with DCIS to better understand whether the immune system can be engaged prior to surgery.

Patients with biopsy-confirmed DCIS receive standard short-term endocrine therapy for approximately 12 weeks before surgery. In one group, patients receive endocrine therapy alone. In the second group, patients receive endocrine therapy combined with the MUC1-targeting vaccine developed by Dr. Finn, given as a series of injections before surgery, with an optional booster dose six months after surgery.

From a clinical perspective, the study is working to address an important question in DCIS management. Not all DCIS progresses to invasive breast cancer, yet many patients undergo surgery and additional treatments. This trial is designed to generate early data on whether an immune-based approach could play a role in future strategies aimed at reducing treatment intensity in selected patients.

“What we are looking at in this study is immunogenicity of the MUC1 vaccine – does it provoke an immune response in patients? And if so, what does that look like?” Dr. Diego asks. “And then, of course, we are examining the safety of the vaccine in terms of any adverse or serious adverse events.

The target enrollment for the study is 50 patients, and as of April 2026, the study had enrolled 30.

Preliminary Immune Response and Safety Data Presented at 2025 San Antonio Breast Cancer Symposium

At the 2025 San Antonio Breast Cancer Symposium (December 2025), Dr. Diego and colleagues presented initial response and safety data derived from the first seven patients to have completed the full trial vaccine regimen.

“Among the first patients who completed the full vaccination protocol, six of seven developed a measurable immune response, which corresponds to an 86% response rate.”

“In contrast, patients in the control arm had no detectable antibodies, which supports that what we are seeing is a true vaccine-induced effect and not a product of random chance,” Dr. Diego says. “Additionally, we have not observed any serious adverse events among patients enrolled in the study, which is an important early signal in terms of safety.”

Second Site Open for Recruitment at UPMC Hillman Cancer Center in Harrisburg

In March 2026, a second recruitment site for the study was opened at UPMC Hillman in Harrisburg to expand the reach of the study and make it feasible for more possible participants. Medical oncologist, Kit Lu, MD, is serving as the site lead at UPMC Hillman in Harrisburg.

“Many of today’s standard-of-care therapies began as treatments studied in clinical trials decades ago,” Dr. Lu says. “Being part of a National Cancer Institute-designated comprehensive cancer network gives our patients in central Pennsylvania access to promising therapies and new diagnostic approaches.”

Opening a second site allows the team to expand beyond Pittsburgh and give patients in central Pennsylvania the opportunity to participate without the burden of travel because, for a study like this, access is a real factor in whether patients are able and willing to enroll.

“Surgery is our first line of defense when it comes to stopping DCIS from progressing to cancer. But it’s not a guarantee, so anything we can do to strengthen the body’s defense gives us hope,” says Brynn Wolff, MD, director of breast surgery, UPMC Magee-Womens in Central Pa. Breast surgeon colleagues Katherine Barton, MD, and Theresa Lee, MD, are also be part of the local study team.

A Difficult Thing to Ask Patients

Patient enrollment in this study depends on a decision that is fundamentally different from most points of discussion in breast cancer care. Dr. Diego’s patients are not weighing treatment options or expected outcomes by participating in this clinical trial. They are being asked to participate in a protocol that will not change their clinical course but rather help answer questions. That distinction changes the nature of the conversation about participating in a trial and introduces a different set of considerations around patient/provider trust, understanding, and motivation for participation.

“We are asking patients to participate in a study where there is no expectation of direct clinical benefit. They are helping us answer a biologic question —whether the vaccine is safe and whether it generates an immune response,” Dr. Diego says. “That is very different from most clinical decisions they are asked to make, and it requires a level of trust and willingness to contribute to something that may not affect their own care. It’s pure altruism at this point for patients. Because of that, it is important that they understand how the study is progressing and what their participation is contributing to. Many of these patients are people I continue to see in my practice, and they become invested in the work. They often become advocates for the study and help others understand why it is important to participate in research and how that contributes to improving care for future patients.”

Patient Referrals and Additional Information

Read the press release on the trial expansion at UPMC Hillman Cancer Center in Harrisburg.

To refer a patient for the clinical trial at UPMC Hillman Cancer Center in Pittsburgh, please call 412-623-6793 or email adamkka2@upmc.edu.

To refer a patient for the clinical trial at UPMC Hillman Cancer Center in Harrisburg, please call 717-545-5000 or email urffera@upmc.edu.

To read the full trial protocol and details, visit ClinicalTrials.gov and enter NCT#06218303 in the search field, or use this link to the trial page.