NEW YORK – Johnson & Johnson on Monday said it will acquire Ambrx Biopharma in an all-cash deal valued at approximately $2.0 billion.
In the deal, approved by J&J's board but yet to be approved by Ambrx shareholders, J&J will acquire all outstanding shares of Ambrx's common stock at $28 per share in cash through a merger of Ambrx with a J&J subsidiary.
J&J will gain Ambrx's pipeline of investigational antibody-drug conjugates (ADCs) including the PSMA-targeted ARX517 in development as a treatment for metastatic castration-resistant prostate cancer (mCRPC), the HER2-targeted ARX788 being assessed in metastatic HER2-positive breast cancer, and the CD-70 targeted ARX305 being studied for treating renal cell carcinoma. The transaction is expected to close in the first half of 2024.
In November, Ambrx reported results from the ongoing Phase I/II APEX-01 trial of ARX517 in patients with metastatic disease who had received at least two prior approved therapies. The primary objectives of the trial are to determine safety and tolerability of ARX517 and establish a recommended Phase II dose. Investigators are also tracking overall survival, progression-free survival, and changes in PSMA expression and exploratory biomarkers.
In the trial, 12 out of 13 patients who had received doses in the therapeutic range had a reduction in prostate specific antigen (PSA) levels of 50 percent or more and 81 percent of patients in that group had a reduction of 50 percent or more in circulating tumor DNA.
The La Jolla, California-based company is also studying the HER2-targeted ARX788 in several clinical trials in advanced breast cancer and solid tumors. In the Phase II ACE-Breast-03 trial, researchers are evaluating the overall response rate in about 71 patients with unresectable or metastatic disease who have had at least one and no more than five prior regimens of systemic therapy in the metastatic setting, including any of the following HER2-targeted treatments: AstraZeneca and Daiichi Sankyo's Enhertu (trastuzumab deruxtecan), Genentech's Kadcyla (T-DM1), or a regimen containing Seagen's Tukysa (tucatinib). In December 2022, Ambrx reported that patients in the study had an overall response rate of 57.1 percent and a 100 percent disease control rate.
Ambrx's partner NovoCodex Biopharmaceuticals, a subsidiary of Zhejiang Medicine, is also testing the drug in a pivotal, Phase II trial, dubbed ACE-Breast-02. The companies said in March that the trial had met its prespecified interim efficacy endpoint by improving progression-free survival compared to a control treatment. Based on those results, NovoCodex is seeking marketing approval for the drug in China.
"The results seen to date with ARX517 in mCRPC are promising and represent a potential first- and best-in-class targeted therapy for the treatment of this aggressive disease," Yusri Elsayed, global therapeutic area head for oncology within J&J's Innovative Medicine division, said in a statement. "In addition, Ambrx's pipeline and ADC platform present exciting future opportunities to deliver enhanced, precision biologics as we look to transform the treatment of cancer and improve patients' lives."