Study of Anti-CD73 Immunotherapy TJD5 in Solid Tumors Launches in China

The first patient has been dosed in a phase 1/2 trial of TJD5 in Chinese patients with advanced solid tumors, according to I-Mab, the company developing the CD73 antibody.

The first patient has been dosed in a phase 1/2 trial of TJD5 (TJ004309) in Chinese patients with advanced solid tumors, according toI-Mab, the company developing the CD73 antibody.1

"It's exciting news that the TJD5 study has been initiated in China. TJD5 represents a promising novel compound targeting the cancer microenvironment. This could bring new hopes to the patients if safety and efficacy could be demonstrated," Yi-Long Wu, MD, tenured professor of Guangdong Lung Cancer Institute, Guangdong Provincial People's Hospital and Guangdong Academy of Medical Sciences, South China University of Technology, chair of Chinese Thoracic Oncology Group, stated in a press release.

Explaining the mechanism action of the CD73 antibody in the press release, I-Mab wrote, “TJD5 is a differentiated, humanized antibody against CD73, an ecto-enzyme expressed on stromal cells and tumors that converts extracellular adenosine monophosphate to adenosine. Adenosine binds adenosine A2A and A2B receptors on immune cells and inhibits immune responses directed against tumors. TJD5 is expected to suppress the immunosuppressive tumor micro-environment and to work in concert with other cancer therapies such as PD-1 and PD-L1 antibodies.”

The open-label, multicenter, dose-escalation/expansion phase 1/2 study (CTR20200445; NCT04322006) is assessing the efficacy, tolerability, and safety of TJD5. Researchers hope to determine the recommended phase 2 doses for additional research with the CD73 antibody as a monotherapy and in combination with toripalimab (Tuoyi) in patients with advanced or metastatic cancers who are refractory/intolerant to available treatments.

The phase 1/2 study is accruing patients aged ≥18 years with an ECOG performance score of 0 or 1.2 Patients must have unresectable or metastatic solid tumors that are histologically or cytologically confirmed; disease progression on or intolerance to standard treatment; or no effective treatments available. Patients cannot enroll if they have had prior T-cell therapy.

"We are pleased to advance TJD5 into the clinical study in China and are committed to realizing the potential of TJD5 as a next-generation immuno-oncology agent," Joan Shen, MD, PhD, CEO of I-Mab stated in the press release. "We have been able to accelerate the Phase 1/2 trial in China by leveraging data from the ongoing Phase 1 clinical study of TJD5 in the United States, which is a testament to our global clinical development capabilities and well-executed pipeline strategies."

"The low response rates to PD-1/PD-L1 inhibitor treatments in cancer patients remain a significant unmet clinical need. As CD73 is widely expressed in various cancers, we hope the combination therapy of TJD5 with toripalimab could provide a potential new transformational treatment option for patients in need," Shen added.

A separate phase 1 trial in the United States is evaluating the efficacy and tolerability of TJD5 as a monotherapy and in combination with the PD-L1 antibody atezolizumab (Tecentriq) in patients with advanced solid tumors.


  1. First Patient Dosed with I-Mab's CD73 Antibody TJD5 in Phase 1/2 Clinical Trial in China for Advanced Solid Tumors. Accessed May 13, 2020. Published May 13, 2020.
  2. A Phase I/II Study of TJ004309 for Advanced Solid Tumor. National Institutes of Health Clinical Trial database. Last updated April 16, 2020. Accessed May 13, 2020.