The humanization of the murine anti-NaPi2b antibody and the generation of a stable cell line for the production of the humanized antibody RebmAb200 - Upifitamab Rilsodotin (UpRi) -, was a pioneering work in Brazil conducted by ReceptaBio. The expression of the RebmAb200 target, NaPi2b, a phosphate transporter protein found in the cell membrane, was evaluated by collaborating researchers at ReceptaBio and high expression was found in breast, lung and ovarian tumors, associated with high specificity, efficiency and sensitivity of the antibody . In July 2015, RebmAb200 was licensed to Mersana Therapeutics, an American biopharmaceutical company that has state-of-the-art technology for the production of ADCs (antibody-drug conjugates). This was the first intellectual property of a drug licensed in Brazil. Preclinical tests using the RebmAb200 with ADC technology from Mersana Inc., which received an award for the best ADC technology platform in 2016, showed great anti-tumor activity in animal models, confirming its potential as a new biopharmaceutical. This ADC - named by Mersana XMT-1536 and newly named UpRi, upifitamab rilsodotin, has been evaluated in a First-in-Human phase Ib/II clinical trial (NCT03319628) in the USA. In 2021, the phase II study of the UpRi in ovarian cancer was started and a phase II study in lung adenocarcinoma (NSCLC) is planned to start in 2021.

A new ADC from the same monoclonal antibody as ReceptaBio, RebmAb200, but with a differentiated technology for toxin conjugation, had its clinical development started in 2020. XMT-1592 is currently being evaluated in a phase Ib clinical study, with phase II planning for ovarian cancer and lung cancer (NCT04396340).

It is a monoclonal antibody that recognizes Lewis blood group B antigen (LeB). As observed for LeY, LeB expression is increased in several types of carcinomas of epithelial origin, such as colorectal, lung, ovary and breast, among others. Notably, elevated LeB expression is correlated with less favorable prognoses of these carcinomas, indicating favorable perspectives for therapeutic use of the antibody in different neoplasms.

The antibody recognizes antigen A34, a glycoprotein belonging to the family of adherent junction molecules. Its expression is particularly high in gastric and esophageal adenocarcinomas. More comprehensive assessment of possible therapeutic uses for RebmAb400 has been carried out in order to better define the development of this monoclonal antibody.