Histrelin Hydrogel Implant--Valera: Histrelin implant, LHRH-Hydrogel implant, RL 0903, SPD 424.

Valera Pharmaceuticals, formerly Hydro Med Sciences, is developing a once-yearly Histrelin Hydrogel Implant [Histrelin implant, LHRH-Hydrogel implant, RL 0903, SPD 424, Vantas], a subcutaneous (s.c.) reservoir device capable of long-term delivery of histrelin at constant release rates for the treatment of prostate cancer. Histrelin is a luteinising hormone-releasing hormone agonist (LHRH). A different formulation of the LHRH implant is currently in development for the treatment of central precocious puberty (CPP). On 4 September 2003, Hydro Med Sciences announced that it had changed its name to Valera Pharmaceuticals. Shire Pharmaceuticals had an option to market and distribute the histrelin implant outside the US, but in a realigned agreement announced in January 2002, Shire stated that HydroMed (now Valera) would be responsible for concluding the phase III studies, filing for regulatory approval and producing the implant, while also gaining marketing rights in the US. Shire has no further involvement in development, but retains an option to market and distribute the product outside the US. The product is available for rest-of-the-world licensing through Valera Pharmaceuticals' business development division. Paladin Labs has received the exclusive rights for the sale and marketing of histrelin hydrogel implant in Canada. Valera Pharmaceuticals will have the responsibility for manufacturing and completing development of the product. In July 2004, Paladin announced it had filed for regulatory approval with Health Canada for the treatment of prostate cancer. Phase III trials have been conducted and initially involved two open-labelled, randomised, parallel studies that compared the hydrogel implant with the active comparators, leuprorelin acetate 22.5 mg depot (TAP Pharmaceutical's Lupron Depot) and a 3-month implant of goserelin acetate (Astra Zeneca's Zoladex). However, because of financial constraints, HydroMed discontinued recruitment in a phase II European study and could not rationalise keeping the comparator arm of the phase III study. The US FDA then gave permission to continue the US part of the programme without the comparator arm, but with appropriate increases in the patient sample size. Patient enrolment in the phase III trial (US and Canada) was completed in July 2002. Valera Pharmaceuticals believes the product may have advantages over standard prostate cancer treatments including reduced costly surgical procedures, lower dosing, increased patient compliance and peace-of-mind, as well as potentially less cost to the patient. The phase III studies were completed in the second half of 2003.CPP arises from the increased release by the pituitary gland hormone gonadotropins and is characterised by an early onset of sexual development in pre-adolescents. Currently, the treatment of CPP involves injections of synthetic gonadotropic hormone-releasing factor agonists such as Supprelin (histrelin acetate) and TAP Pharmaceutical's Lupron Depot-Red (leuprolide acetate) every 28 days, a potentially painful procedure. This treatment inhibits pituitary release of gonadotropins. Valera's histrelin implant is a compact, removable subcutaneous implant that can be applied under a local anaesthetic in doctor's surgery.