Dr Gonzalez-Martin on the Rationale for Targeting NaPi2b in Ovarian Cancer

“TUB-040 is a new ADC with an exatecan payload and a stable linker. [The agent] targets NaPi2b, [which is] a very interesting target in ovarian cancer because it is highly expressed [on cancer cells] and is a transporter.”

Antonio Gonzalez-Martin, MD, the head of the Department of Medical Oncology at Clinica Universidad de Navarra, the director of the Cancer Center Clinica Universidad de Navarra, and an associate professor of medicine at Francisco de Vitoria University, discussed the clinical rationale for targeting sodium-dependent phosphate transport protein 2b (NaPi2b) for the treatment of patients with ovarian cancer.

Patients with platinum-resistant ovarian cancer represent a high unmet need and lack sufficiently active treatments, Gonzalez-Martin began. Exploring treatment with antibody-drug conjugates (ADCs) represents an important area of therapeutic development for these patients, he continued.

The novel ADC TUB-040 could represent a new treatment option for patients with platinum-resistant disease, Gonzalez-Martin noted. The agent is comprised of an exatecan payload and a stable linker and targets NaPi2b, he explained. NaPi2b represents an attractive treatment target in ovarian cancer because it is highly expressed on the cancer cells and is a transporter protein, he added.

During the 2025 ESMO Congress, Gonzalez-Martin presented data from the phase 1/2a NAPISTAR1-01 trial (NCT06303505), which was a dose escalation study of TUB-040 in patients with platinum-resistant, high-grade serous epithelial ovarian, fallopian tube, or primary peritoneal cancer.

Patients needed to have an ECOG performance status of 0 or 1, have received a maximum of 5 platinum-based and 2 non-platinum based prior lines of therapy, and have no received a prior ADC containing a TOPO-I inhibitor payload in order to be eligible for the study. The objectives of the study included safety and tolerability, determining the maximum tolerated dose, overall response rate per RECIST 1.1 criteria, disease control rate, progression-free survival, and overall survival.