Moffitt trial tests personalized immunotherapy as a replacement for chemotherapy in early HER2-positive breast cancer

Moffitt Cancer Center in Tampa is enrolling women with early-stage HER2-positive breast cancer in a clinical trial that tests whether a personalized immunotherapy, a dendritic cell vaccine made from each patient's own blood, can take the place of chemotherapy, FOX 13 reported Wednesday, Oct. 14. The study is open to patients with stage 1 or stage 2 disease and tumors smaller than 3 centimeters, and the trial's lead oncologist says it is still accepting patients.

The research is early, and no results from the chemotherapy-free approach have been published. But it builds on years of Moffitt studies in which the same vaccine, combined with reduced chemotherapy, produced strong tumor responses, and it could eventually spare some patients from one of the hardest parts of cancer treatment.

How the vaccine works

Dendritic cells are immune cells that help the body recognize threats and direct other immune cells to attack them. In the Moffitt approach, doctors draw a patient's blood and manufacture a vaccine tailored to that patient in the cancer center's cell therapy lab. The vaccine is then injected directly into the breast tumor.

Dr. Heather Han, a Moffitt medical oncologist who leads the research, told FOX 13 that the vaccine is manufactured in Moffitt's cell therapy vaccine lab from a sample of the patient's blood. "And these dendritic cell vaccines are designed to make tumor microenvironment better, to increase immune infiltration. So potentially, they can attack the cancer cells and also help the treatment work better." Moffitt's website lists the physician as Dr. Hyo Han.

The vaccine is designed to target HER2, a protein that drives the growth of HER2-positive tumors. Han described HER2-positive disease as one of the most aggressive and difficult-to-treat forms of breast cancer, and one of its three most common types.

Who is eligible

According to Han, patients must meet these criteria, as reported by FOX 13:

• A diagnosis of HER2-positive breast cancer
• Stage 1 or stage 2 disease
• A tumor measuring less than 3 centimeters

Patients can be prescreened by calling Moffitt at 813-861-2753 or 1-855-370-0152, according to FOX 13. Moffitt has said its dendritic cell vaccine trials for HER2-positive breast cancer are available only at its Tampa campus, which means patients from elsewhere in Florida and beyond would travel to Tampa for treatment.

Moffitt has not said how many patients the new study will enroll or when results might be published, FOX 13 reported. Earlier Moffitt materials describing plans for the chemotherapy-free arm said it would test the vaccine alongside the HER2-targeted antibodies trastuzumab and pertuzumab, without chemotherapy, before surgery. That work is supported by a $1.5 million Florida Department of Health grant awarded to Han, according to Moffitt. A Moffitt listing of the award describes it as a chemotherapy-free treatment regimen for HER2-positive breast cancer using HER2-directed intratumoral dendritic cell immunotherapy plus trastuzumab and pertuzumab.

What earlier studies found

The chemotherapy-free study is the latest step in a series of Moffitt trials. In each, patients received the vaccine before surgery, a strategy known as neoadjuvant treatment.

A phase 1 trial, published in JAMA Oncology, tested HER2-targeted therapy plus the dendritic cell vaccine given before a reduced, or de-escalated, chemotherapy regimen. Moffitt reported that the combination was safe and well tolerated. Twelve patients received weekly vaccine injections for six weeks, followed by 12 weeks of weekly paclitaxel chemotherapy. Breast MRIs showed nine of the 12 had objective responses, three complete and six partial, while three had stable disease. Seven patients had no remaining invasive cancer when their tumors were examined after surgery, a result called a pathologic complete response, according to Moffitt. That study also set the dose, 100 million dendritic cells, used in the next trial.

The follow-up phase 2 trial, called NATASHA, enrolled 47 HER2-positive patients at Moffitt, roughly half with hormone receptor-positive disease and half with hormone receptor-negative disease. Results presented at the American Society of Clinical Oncology annual meeting in 2026 reported pathologic complete response in about half of the hormone receptor-positive patients and in most of the hormone receptor-negative patients, though Moffitt's announcement and the meeting abstract gave slightly different figures for the second group. Moffitt reported that, nearly 17 months after surgery, no patients in the trial had seen their cancer return. That follow-up period is short, and longer tracking is needed to show whether the benefit lasts.

What doctors hope to learn

Han told FOX 13 that the goal is a higher cure rate without recurrences. "We are hoping that this treatment could potentially lead to a higher cure rate without the patient experiencing recurrences following this treatment," she said.

She also said preliminary laboratory and patient data suggest the vaccine does more than shrink the injected tumor. "There is also data that this immunotherapy, the vaccine therapy, can potentially clear metastasis initiating cells," Han said, referring to cells that can seed cancer elsewhere in the body.

Han said preliminary data indicate that some patients receiving the immunotherapy have not required surgery, according to FOX 13. Moffitt has not published those data, and it is not clear how many patients that describes or how long they have been followed. Those findings should be treated as early observations, not proof that the approach works.

Why replacing chemotherapy matters

Chemotherapy remains a standard part of treatment for many HER2-positive breast cancers, but its toxic side effects can take a heavy physical toll. FOX 13 reported that Moffitt's researchers designed the current study to evaluate immunotherapy without chemotherapy after seeing significant success combining the vaccine with less intense chemotherapy.

If later trials confirm the benefit, the approach could let some patients with smaller, early-stage tumors avoid chemotherapy altogether. That is a large if. Small single-center studies often produce encouraging early results that do not hold up in larger randomized trials, and the vaccine has not been approved by the U.S. Food and Drug Administration for any use.

What's next

Moffitt continues to enroll patients and has not set a timeline for reporting results. Patients with early-stage HER2-positive breast cancer who are interested should talk with their oncologist about whether the trial fits their situation, since joining a study can affect the timing and choice of standard treatment. Prescreening is available through the Moffitt phone lines listed above.