Human health and medicine

Treatment Expectations

Treatment expectations: anticipated outcomes of a healthcare treatment (MeSH D000099055, 2025). Positive expectations predict better pain, depression, and acupuncture outcomes; negative ones drive nocebo effects.

Treatment Failure

Treatment failure: unsuccessful result of medical management, a MeSH-indexed outcome since 1993. Defined per field: TB positive cultures at 4-5 months, clozapine-eligible schizophrenia, two failed antidepressant trials, and trial endpoints.

Treatment of acute lymphoblastic leukemia

Treatment of acute lymphoblastic leukemia is a phased, multi-drug program lasting roughly two to three years, combining chemotherapy with CNS-directed therapy, targeted antibodies, and engineered cell therapies.

Treatment of chronic lymphocytic leukemia

Treatment of chronic lymphocytic leukemia begins only for symptomatic or progressive disease, using targeted drugs such as BTK inhibitors and venetoclax, which have largely replaced chemoimmunotherapy.

Treatment of Langerhans cell histiocytosis

Treatment of Langerhans cell histiocytosis (LCH) ranges from observation of single bone lesions to chemotherapy, BRAF inhibitors, or stem cell transplantation, with vinblastine plus prednisone standard in children.

Treatment Outcome

Treatment Outcome (MeSH D016896, introduced 1992): evaluation of results of disease management and procedures to determine efficacy, effectiveness, safety, and practicability; covers endpoints like progression-free survival and treatment failure.

Treatment Switching

Treatment switching: patients in a randomized clinical trial (MeSH heading, 2021) leave their assigned arm, usually control to experimental in oncology trials; ITT survival estimates become biased and methods like RPSFTM, IPE, IPCW, and two-stage estimation adjust for it.

Treatment-resistant depression

Treatment-resistant depression (TRD) is major depression unresponsive to at least two adequate antidepressant trials; no consensus definition exists, prevalence reaches about 15%, and key treatments include ECT, rTMS, and ketamine or esketamine.

Trebananib

Trebananib (AMG 386) is Amgen's investigational Ang1/Ang2-neutralizing peptibody blocking the Tie2 angiopoietin pathway; it extended PFS but not overall survival in ovarian cancer phase 3 TRINOVA trials and was never approved.

TREGZI

TREGZI (Orca-T), allogeneic regulatory T cell immunotherapy with HSPC and T cells-vldq, is Orca Bio's FDA-approved (June 30, 2026) cell therapy for matched donor stem cell transplant in adults with hematological malignancies, improving cGVHD-free survival.

Trehalase deficiency

Trehalase deficiency (isolated trehalose intolerance, TREH gene, 11q23.3, rs2276064) is a rare autosomal dominant intestinal disorder causing osmotic diarrhea after eating mushrooms; found in about 8% of Greenlanders but rare elsewhere.

Trelagliptin

Trelagliptin (SYR-472, Zafatek) is a once-weekly oral DPP-4 inhibitor for type 2 diabetes, approved in Japan in March 2015 as the first once-weekly oral antidiabetic; 100 mg weekly, non-inferior to daily alogliptin.

Tremelimumab

Tremelimumab (tremelimumab-actl, Imjudo; formerly ticilimumab, CP-675,206) is AstraZeneca's human IgG2 anti-CTLA-4 monoclonal antibody, FDA-approved in 2022 with durvalumab for unresectable hepatocellular carcinoma and metastatic NSCLC.

Tremor

Tremor, also called shaking, is an involuntary rhythmic oscillatory movement and the most common movement disorder. Classified as resting or action tremor; key types are essential tremor and parkinsonian tremor, treated with propranolol, levodopa, DBS, or focused ultrasound.

Trench foot

Trench foot, or immersion foot, is a nonfreezing cold injury caused by prolonged exposure of the feet to cold, wet conditions, first described in Napoleon's army in 1812.

Trendelenburg position

Trendelenburg position: supine head-down tilt with feet raised above the head, named for German surgeon Friedrich Trendelenburg (1844-1924). Used in pelvic laparoscopic surgery and central line placement; evidence does not support its use for hypotension, where passive leg raising serves as a diagnostic test.

Trendelenburg's sign

Trendelenburg's sign: drop of the pelvis on the unsupported side during single-leg stance, indicating hip abductor (gluteus medius/minimus) weakness; described by Friedrich Trendelenburg in 1897, tested over 30 seconds, with modest diagnostic accuracy.

Trenonacog alfa

Trenonacog alfa (IB1001, IXINITY) is a standard half-life recombinant human factor IX, Thr148 variant made in CHO cells, FDA-approved for hemophilia B prophylaxis, bleeding treatment, and surgery; its EU application was withdrawn in 2013.

Treosulfan

Treosulfan (Grafapex, Trecondi) is an alkylating prodrug used with fludarabine as conditioning before allogeneic stem cell transplantation in AML and MDS; FDA approved January 2025, EU 2019.

Trepanning

Trepanning (trepanation, trephination): drilling, scraping, or cutting a hole in the skull, practiced for some 7,000 years worldwide, codified by Hippocrates, and surviving today as craniotomy, burr holes, and craniectomy.

Treponema Immobilization Test

The Treponema immobilization test (TPI) is a serologic test for syphilis introduced in 1949, which detects antibody that stops the movement of live Treponema pallidum organisms.

Treponema pallidum

Treponema pallidum, the syphilis spirochete (Spirochaeta pallida), an obligate human spirochete bacterium discovered in 1905; subspecies pallidum, pertenue, and endemicum cause syphilis, yaws, and bejel, distinguished by a stealth outer membrane lacking lipopolysaccharide.