FOSTER CITY – November 10, 2026 -- OrthoTrophix reported that femoral bone shape stabilized in knees treated with its osteoarthritis candidate TPX-100, while it kept changing in placebo-treated knees, according to two posters presented at ACR Convergence 2026 in Orlando (November 6-11).
MRI analysis links B-score to meniscal pathology
Poster #1581, presented November 9, is a retrospective MRI analysis of a one-year, double-blind Phase 2a study of intra-articular TPX-100 in knee osteoarthritis (KOA). Femoral bone shape, measured by B-score, was significantly associated with baseline meniscal pathology at 6 and 12 months.
In placebo-treated knees, the bone-meniscus link strengthened over time. In TPX-100-treated knees, bone shape stabilized and the link weakened. The company says this suggests TPX-100 may alter the structural course of KOA in patients with high meniscal disease burden.
Patients with severe meniscal damage show larger functional gains
Poster #2568, presented November 10, found that patients with more severe baseline meniscal pathology achieved greater, more durable improvements in patient-reported outcomes on TPX-100 than on placebo. Gains were largest in knee function, measured by a validated subscale of 17 everyday activities that includes walking, climbing stairs and rising from a chair.
Exploratory findings require prospective confirmation
Both analyses are exploratory. Chief Medical Officer Dawn McGuire said that, if confirmed prospectively, the results could help identify patients especially likely to benefit from TPX-100 and strengthen B-score as an objective marker of structural progression.
OrthoTrophix, which is privately held, has partnered with American Regent on TPX-100 for the U.S. market and retains rights for the rest of the world. The company describes TPX-100 as a disease-modifying osteoarthritis drug (DMOAD) candidate.