Safer yellow fever vaccine is currently in clinical studies: Xcellerex

XRX-001, a new preventive vaccine against yellow fever, is currently in human trials, according to Xcellerex, Inc, the developer of the vaccine.

XRX-001 is an inactivated virus vaccine adsorbed to alum adjuvant.

The only currently available yellow fever vaccine (17D vaccine) is an attenuated, live vaccine with rare but potentially serious adverse effects.

Because XRX-001 is inactivated and non-replicating, it is anticipated to significantly reduce the risks of serious and fatal adverse events that are sometimes associated with the live yellow fever vaccine.

The absence of foreign proteins derived from hens’ eggs in XRX-001 should also reduce the risk of allergic reactions and eliminate the need to exclude egg-allergic people from vaccination.

The double-blind, controlled Phase I XRX-001 trial will enroll 60 healthy subjects divided into three groups.

Two groups of volunteers will receive two different dose levels of XRX-001 and the third will receive placebo.

The primary objective of the trial is to evaluate the safety and tolerability of XRX-001 vaccine, and secondary objectives will assess the neutralizing antibody response–an accepted correlate of protective immunity to yellow fever.

In a second parallel trial, the Company will compare the antibody response in those receiving XRX-001 to travelers receiving the currently-marketed vaccine.

“The introduction of a non-replicating vaccine against yellow fever into clinical development is important because there are increasing constraints on the use of the live vaccine,” stated Dr. Thomas Monath, Acting Chief Medical Officer for Xcellerex.

Approximately one million people travel annually from the U.S. to yellow fever endemic areas and would benefit from vaccination, he hoped.

What is yellow fever?

Yellow fever is a hemorrhagic fever caused by a virus spread by mosquitoes.

XRX-001 occurs in tropical areas of Africa and South America, affecting travelers to and residents of those areas.

The incubation period (time from infection to illness) is usually 3-6 days.

Approximately 15% of yellow fever infections cause severe damage to liver, heart and kidney, bleeding and shock. Twenty to 50 percent of people with the more severe form of yellow fever die of the disease.

There is no specific treatment for the disease, but contracting yellow fever is preventable through vaccination.

The currently available live, attenuated vaccine (17D vaccine) was developed in 1936 and approximately 30 million people traveling to or living in endemic regions are vaccinated annually.

The safety of this vaccine has only been questioned since 2001 when serious adverse events resembling yellow fever disease were first reported.

Xcellerex has single-use component technology platform enables the development of biotherapeutics and vaccines, thereby dramatically improving the ability of Xcellerex and its partners to deploy manufacturing capacity.