Thypinone, Relefact TRH
Evidence Grade B — Strong clinical evidence. 121 published studies, 102 human. 15 registered clinical trials.
Protirelin (previously sold as Thypinone and Relefact TRH) is synthetic TRH — the brain hormone that controls thyroid function. It was used as a diagnostic injection to test pituitary function but has been discontinued from the US market after advances in blood test sensitivity made the provocative test unnecessary. It is notable as one of the smallest biologically active hormones known (just three amino acids), and its discovery contributed to a Nobel Prize in 1977.
121 published studies: 102 human, 13 animal, 4 in-vitro, 6 reviews
Protirelin was previously marketed as Thypinone (Abbott) and Relefact TRH (Hoechst). The TRH stimulation test was a standard endocrine diagnostic procedure from the 1970s through the 1990s. It was discontinued from the US market in the early 2000s after advances in laboratory TSH measurement eliminated the need for a provocative test in most clinical scenarios.
Protirelin is notable as the smallest known biologically active peptide hormone (just three amino acids) and its discovery contributed to a Nobel Prize in Physiology or Medicine in 1977.
When injected intravenously, protirelin stimulates the pituitary to release TSH. In a healthy person, TSH rises predictably within 20–30 minutes. The pattern of response — whether exaggerated, normal, or absent — helped clinicians distinguish between different types of thyroid and pituitary disorders. This diagnostic utility was replaced by third-generation TSH assays that can detect extremely low TSH levels directly from a blood sample.
Research suggests protirelin's diagnostic utility was well established from the 1970s through the 1990s but was made obsolete by third-generation TSH assays that can detect extremely low TSH levels directly from a blood sample, eliminating the need for an injection-based test. Rare but serious adverse events included pituitary apoplexy in patients with undiagnosed large pituitary tumours. A related compound (taltirelin, an oral TRH analogue) is approved in Japan for a neurological condition, and TRH-based approaches are being explored for traumatic brain injury. No active development exists for protirelin itself in major markets.
A Long-Term Study of KPS-0373 in Patients With Spinocerebellar Degeneration (SCD)
A Study of KPS-0373 in Patients With Spinocerebellar Degeneration (SCD)
A 24-week Open-label Study of KPS-0373 in Patients With Spinocerebellar Degeneration (SCD)
An Extension Study of KPS-0373 in Patients With Spinocerebellar Degeneration (SCD)
Phase II Study of KPS-0373 in Patients With Spinocerebellar Degeneration (SCD)
Health Canada Market Authorisation
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