Fostemsavir is a first-in-class HIV-1 attachment inhibitor and a prodrug of temsavir. It is an antiretroviral pharmaceutical ingredient developed for the treatment of multidrug-resistant HIV-1 infection in heavily treatment-experienced adults with limited treatment options. Fostemsavir is converted in the body to the active moiety temsavir, which targets the HIV-1 envelope glycoprotein gp120.
Fostemsavir is a specialized antiretroviral API used in pharmaceutical development and HIV treatment formulations. It is administered orally and is designed to provide systemic exposure to temsavir, the active HIV-1 attachment inhibitor.
CAS Number: 864953-39-9
Molecular Formula: C25H26N8O5
Molecular Weight: 502.53 g/mol
Development Code: BMS-663068
Active Moiety: Temsavir
Drug Class: HIV-1 Attachment Inhibitor
Therapeutic Class: Antiretroviral
Therapeutic Area: HIV / Infectious Diseases
Fostemsavir is hydrolyzed to temsavir after administration. Temsavir binds to the HIV-1 envelope glycoprotein gp120 and interferes with the interaction between HIV-1 and the CD4 receptor on host cells. This prevents viral attachment and entry into susceptible CD4 T cells and other target cells.
Fostemsavir is used in combination with other antiretroviral agents for the treatment of multidrug-resistant HIV-1 infection in heavily treatment-experienced adults who have limited treatment options because of resistance, intolerance or safety considerations with their current antiretroviral therapy.
Fostemsavir is the phosphate prodrug, while temsavir is the active moiety responsible for antiviral activity. The prodrug is designed to improve the pharmaceutical properties and oral delivery of temsavir.
Fostemsavir is a phosphate-containing prodrug with a nitrogen-rich heterocyclic structure. Its molecular formula is C25H26N8O5 and molecular weight is approximately 502.53 g/mol. Fostemsavir is converted to temsavir through hydrolysis after administration.
Fostemsavir API quality evaluation may include identification by IR, HPLC and LC-MS, assay by HPLC, related substances, water content, residual solvents, elemental impurities and other applicable pharmaceutical quality-control tests. Validated analytical methods should be used for commercial pharmaceutical release.
Fostemsavir should be stored in tightly closed containers under controlled pharmaceutical conditions and protected from excessive heat, moisture and direct light. Material should be handled according to applicable stability data and product-specific storage requirements.
Fostemsavir represents a distinct mechanism within antiretroviral therapy because it targets the viral attachment process rather than the commonly targeted HIV reverse transcriptase or protease enzymes. Its active moiety, temsavir, binds to gp120 and interferes with HIV-1 entry into host cells.
Fostemsavir is an oral HIV-1 attachment inhibitor prodrug of temsavir. It is identified by CAS Number 864953-39-9, with molecular formula C25H26N8O5 and molecular weight 502.53 g/mol. It is used with other antiretroviral medicines for heavily treatment-experienced adults with multidrug-resistant HIV-1 infection and limited treatment options.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | ≤2.0% |
| Residue on Ignition | ≤1.0% |
| Heavy Metals | NMT 20 ppm |
| pH (1% Solution) | 5.0 – 7.0 |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |
| Water Content | NMT 1.0% |