Joseph Fraietta, PhD

Ovarian cancer remains the deadliest of the gynecologic cancers, and three obstacles account for much of that lethality. Tumors surround themselves with a dense, fibrous shield that blocks immune cells from entering. Not every tumor cell carries the same markers, so cells that lack the one being targeted survive treatment and regrow the disease. And the environment inside the tumor wears down whatever defenders manage to get in. CAR (chimeric antigen receptor) T-cell therapy, which reprograms a patient’s own T cells to recognize and kill cancer cells, has transformed the treatment of blood cancers, but these barriers have kept it from delivering comparable results here.

Our institution has tested that proposition directly. We have run CAR T cell trials targeting mesothelin and folate receptor-alpha (FRα), two proteins found broadly on ovarian tumors, and while both proved safe, neither produced lasting benefit. Few of the infused cells reached the tumor, and those that did failed to settle in as tissue-resident memory cells, the long-lived form T cells must adopt to persist inside tissue. The problem was not the target. It was the terrain, and how long our cells could hold it.

Our recent work points toward a solution with three coordinated parts. We combined mesothelin CAR T cells with VCN-01, a tumor-killing virus engineered to carry an enzyme that digests the fibrous shield. In the first patients to receive it, the combination produced a partial response, but the CAR T cells still did not persist well, and still could not reach every tumor cell. Separately, we found that briefly conditioning CAR T cells with a signaling protein called TGF-beta pushes them toward that resident state while preserving their killing power. We also developed a bispecific antibody: a two-armed molecule that grabs a cancer cell with one arm and a T cell with the other, forcing them together. Ours targets mesothelin while ignoring the decoy fragments ovarian tumors shed to misdirect an attack, and the CAR T cells can manufacture it themselves.

This proposal tests whether those pieces work better together than apart. Our central idea is that VCN-01 does more than open a door: by clearing the shield and releasing signals that draw immune cells in, it creates local conditions where FRα-targeted CAR T cells can take up residence and stay. Aim 1 will determine whether the virus creates those conditions, and measure how long CAR T cells persist inside tumors after priming with it. Aim 2 will ask whether the bispecific antibody closes the escape route left open by targeting one marker alone, recruiting the patient’s own T cells against tumor cells that lack FRα without exhausting the engineered cells.

The novelty of this work lies in a single framework that prepares the ground, programs T cells to hold it, and amplifies local immunity to close the escape routes that limited earlier CAR T therapies. Because several of these components have already been tested in patients at our center, this study is positioned to define the dose, route, and timing needed for a first-in-human trial, and to reveal more broadly how a tumor’s structure, signals, and shifting markers govern whether immunotherapy succeeds, in ovarian cancer and beyond.

“I want this to become a durable outpatient treatment for ovarian cancer. That’s my dream, particularly for women with platinum‑resistant disease, where today the options are very limited and the outcomes are poor. I want to see remissions measured in years, not months.”