TiumBio said it would release study results showing that its investigational immunotherapy has superior immune activation than MedPacto’s vactosertib.
MedPacto brushed off TiumBio’s announcement, calling it “meaningless,” but the company seemed upset about it at the same time.
TiumBio disclosed the abstract of a pre-clinical trial of TU2218 on the American Association for Cancer Research (AACR) website, which is to hold AACR Annual Meeting 2022 in April.
TU2218 is a new immunotherapy candidate, inhibiting ALK5 (TGF-ß receptor) and VEGFR-2. As the two are considered one of the causes of low response rates of immune checkpoint inhibitors, the dual inhibitor is expected to raise the response rate of an immune checkpoint inhibitor, the company said.
TiumBio said in the abstract, “In a human PBMC (peripheral blood mononuclear cell) assay, 0.5-1 μM TU2218 treatment significantly enhanced IFN-γ (interferon-gamma) production or IFN-γ-producing T lymphocytes number by TGF-β-driven immunosuppression, but vactosertib, galunisertib and TGF-β neutralizing antibody did not have significant effects.”
Vactosertib and galunisertib, mentioned by TiumBio, are both immune-oncology therapeutic candidates inhibiting TGF-ß.
Eli Lilly attempted a combination therapy of Opdivo (nivolumab) and galunisertib but discontinued the development in 2020 due to hepatotoxicity. MedPacto is working on vactosertib as immunotherapy and testing it in a combo with MSD’s anti-PD-1 immunotherapy Keytruda (pembrolizumab) in a phase 2 study.
TiumBio’s abstract drew the industry’s attention because it directly mentioned a rival company’s investigational therapy in an international academic event.
TiumBio said its study aimed to compare the immune activation effects of TGF-ß inhibitors.
“We conducted the test with a healthy person’s normal blood. As TU2218 and vactosertib can activate immune cells by inhibiting TGF-β, we investigated how much TU2218 raises IFN-γ levels compared to other rival candidates,” an official at TiumBio said.
In the TGF-β-related experiment, TU2218 increased IFN-γ levels significantly, the official went on to say. As the levels were much higher than the normal level, the company judged that TU2218 could activate immune cells to make T cells and NK cells more active, and an injection of an anti-PD-(L)1 antibody could make immune cells even more active, he added.
However, MedPacto said TiumBio’s abstract was absurd.
“It's not even worth mentioning,” an official at MedPacto said. “I don’t know how TiumBio designed the study, but it is a preclinical result, and interferon-gamma is not a target of TGF-β inhibitors, including vactosertib. So the comparison is meaningless.”
The official even said TiumBio might have wanted to “embellish study results” by mentioning MedPacto’s vactosertib.
Every year, the AACR holds a meeting to share basic and clinical research on cancer. The annual meeting will be held in New Orleans, the U.S., from April 8-13. Online-only posters will be disclosed on the first day, April 8.