Vivesto completes recruitment in Paccal Vet study in cats and determines maximum tolerated dose

VIVEPress release01.07.2026 klo 09.00

Solna, Sweden, July 1, 2026 – Vivesto AB, an oncology-focused development company, today announced that recruitment has been completed in the company’s ongoing Paccal Vet dose-finding study in cats with solid tumors. A total of 21 cats have been enrolled, with clear indications of anti-tumor effects observed, and the maximum tolerated dose (MTD) has been determined. Final results are expected in Q4 2026.

The primary objective of the study was to determine the MTD of Paccal Vet (paclitaxel micellar) in cats. In addition to establishing an appropriate dose for further development, the study includes exploratory assessments of Paccal Vet anti-tumor activity across diverse tumor types such as lymphoma and carcinoma. Cats with difficult-to-treat solid tumors, often after previous treatment options failure, have been included in the study.

“The completion of recruitment and MTD determination represent important progress for our Paccal Vet program in cats. The higher-than-expected MTD reflects the favorable tolerability observed during the study and provides us with a broader data set for assessing safety, dosing and early signs of anti-tumor activity. In parallel, initial signs of clinical responses on have been observed across several tumor types and dose levels, indicating that Paccal Vet could become a valuable treatment opportunity of cats who currently have no approved cancer therapies,” said Erik Kinnman, CEO of Vivesto.

The study was initially designed to include up to 12 cats in a 3+3 dose-escalation design. Recruitment was subsequently expanded as Paccal Vet was tolerated better than anticipated, allowing the study to continue into higher dose cohorts and include additional patients. In the study, cats are treated with up to four treatment cycles of Paccal Vet at three-week intervals across three clinical sites in the US. The study remains ongoing while enrolled cats complete treatment. The final results, expected in Q4 2026, are intended to support the next steps in the development of Paccal Vet for cats with cancer.

About Vivesto AB

Vivesto is a Swedish development company that aims to offer new treatment options for hard-to-treat cancers where there are major medical needs and significant market potential. The project portfolio consists of Cantrixil, which is being developed for blood cancer, and the veterinary oncology program Paccal Vet (paclitaxel micellar), which is being evaluated in a pilot clinical trial in dogs with splenic hemangiosarcoma following splenectomy and in a dose-finding study in cats with solid tumors. Vivesto’s shares are traded on Nasdaq Stockholm (ticker: VIVE). Visit www.vivesto.com for more information about Vivesto.

About Paccal Vet
Vivesto’s drug candidate Paccal Vet consists of paclitaxel formulated with the company’s proprietary XR-17 technology, which enables solubility without the undesirable effects of traditional formulations containing solvents. The absence of the solvent cremophor, to which cats and dogs are particularly sensitive, may reduce the risk of serious side effects and death associated with treatment.

Paccal Vet also does not require the addition of human albumin, which when used in cats and dogs can cause hypersensitivity reactions and reduced treatment effectiveness. Previous clinical studies performed by Vivesto have demonstrated safety in more than 300 dogs. Anti-tumor activity has also been shown in squamous cell carcinoma and non-resectable mammary carcinoma of stage III-V. Vivesto is also conducting a Paccal Vet dose-finding study in cats with solid tumors.

About cancer in cats
The need for safe and effective cancer treatment in cats is vast and increasing as the number of pets grows. Estimates indicate that there are more than 95 million cats in the United States alone and approximately 6 million of those are diagnosed with cancer each year. There are currently no approved drugs for the treatment of cancer in cats and current paclitaxel formulations are not tolerated by cats and therefore cannot be used.