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Interferon alpha-2b is an anti-viral drug originally approved as an injection in the mid-1980s (Intron A, Schering Corporation). It is currently approved for indications including melanoma, hepatitis C, and ano-genital warts (AGW)—a condition caused by human papilloma virus ( HPV). Interferon alpha-2b injection can lead to serious systemic neuropsychiatric, autoimmune, ischemic, and infectious side effects. Fear of adverse events or the injection itself can negatively impact patient compliance and, in the case of AGW, intralesional injection into sensitive genital tissues is rarely prescribed.
Helix BioPharma Corp. has applied its Biphasix topical drug delivery technology to simplify administration, thus reducing side effects and accessing new dermatological indications for interferon alpha-2b. Biphasix is a proprietary technology developed by Helix that enables the topical administration of large hydrophilic or lipophilic molecules that would normally have to be injected. Interferon alpha-2b is encapsulated in multilamellar vesicles, which are then incorporated into a cream matrix (Figure 1). The matrix is theorized to help increase skin solubility and allow the drug payload to permeate the outer layer of the skin. Topical administration of interferon alpha-2b aims to target diseased epidermal tissues locally, thereby limiting systemic exposure and increasing patient compliance.
Helix has focused on certain HPV-induced conditions as the initial indications for topical Interferon alpha-2b. HPV is a common sexually-transmitted infection that affects approximately 20 million Americans, with 6 million more infected each year.1 Two of the most common clinical manifestations of HPV infection are cervical dysplasia and AGW. Women with abnormal cervical cells must be closely monitored as the condition can progress to cervical cancer. Surgical intervention is required if the condition does not regress because there are no pharmacological interventions to treat cervical dysplasia. AGW can be treated with intralesional injections of Intron A or via topical administration of imiqumod. Unfortunately, both options have administration and tolerability issues.
Topical Interferon alpha-2b is currently in Phase 2 trials for both cervical dysplasia and AGW. A Phase 2 trial was completed in patients with cervical dysplasia and a Phase 2 trial for AGW has achieved last-patient-out status. In the completed cervical dysplasia trial, about 47% of the women treated with Topical Interferon Alpha-2b had their Pap smears revert back to normal after 12 weeks, compared to 16% of control patients.2
Topical Interferon alpha-2b could be the first pharmacological treatment for HPV related cervical dysplasia and a more tolerable alternative to currently available agents for the treatment of AGW. Topical Interferon alpha-2b may have applications for treating other dermatological diseases including forms of skin cancer. Biphasix is a unique enabling technology capable of reformulating other old injectable drugs for new topical purposes.
References
1. Centers for Disease Control and Prevention. Genital HPV Infection – CDC Fact Sheet. Sexually Transmitted Diseases. Accessed on May 17, 2010. Available at https://www.cdc.gov/STD/HPV/STDFact-HPV.htm.
2. Helix BioPharma Corp. Topical Interferon Alpha-2b.” Annual Report: 2008 Annual Report. Accessed on May 17, 2010. Available from https://www.helixbiopharma.com/Portals/0/investors/Annual Report/English/HelixAR2008_SedarFile_Final.pdf.
This article was published in Drug Discovery & Development magazine: Vol. 13, No. 4, May 2010, p. 22.
Filed Under: Drug Discovery
