Of all the industrialized countries of the world,
Japan has the highest rate of hepatitis C (HCV). It also has one of the
oldest and most varied histories of hepatitis C in the world among the
industrialized modern nations. Approximately 1.5 to 2 million Japanese
are infected with hepatitis C. Approximately 70% of the Japanese
population infected with hepatitis C has HCV genotype 1b, and 30% are
infected with genotype 2a/b.
The History of HCV in Japan
Modern medicine and public health came early to
Japan in the late 1800’s. In the early 1900’s, the discovery of the
hypodermic needle and a drug to treat schistosomiasis would transmit
hepatitis C throughout Japan.
Schistosomiasis is a disease caused by a worm that
lives in water snails. When people wade in water to work on
agriculture the worm enters the human body and lays eggs. The eggs
hatch and travel to the liver. Schistosomiasis causes damage to the
liver, the gastrointestinal system, kidneys, and genitals. It can,
over time, cause death. In some parts of the world, it is considered
as deadly as malaria. The first treatment developed to treat
schistosomiasis consisted of multiple intravenous injections of
antimony sodium tartrate. By the 1970’s there were approximately 10
million intravenous injections given to people in Japan. The same type
of eradication program was conducted in Egypt, and a similar epidemic
of HCV is seen in Egypt. As in Egypt, treatment of schistosomiasis was
the beginning of the HCV epidemic in Japan. The injections were given
with used or unsterile hypodermic needles.
Nagai Nagyoshi discovered methamphetamine in 1893.
Dr. Akira was able to synthesize it into crystalline meth in 1919.
Widespread use of methamphetamine use did not begin until World War l
when it was used as an injectable treatment for asthma. The large
scale use came later during World War II when it was prescribed as an
oral and injectable stimulant for tired soldiers, pilots, and ammunition
workers during the war. After the war methamphetamine was prescribed
for general post-war trauma. In 1949, Japan banned the manufacture of
methamphetamine, but illegal methamphetamine use continued as did the
hepatitis C epidemic.
Modern Japan and Hepatitis C
Hepatitis C and its complications are the leading
cause of liver cancer in Japan. Japan has the highest rates of liver
cancer in industrialized countries. HCV is the 4th leading cause of
death among Japanese men and the 5th leading cause of mortality among
Japan has a multi-layered
healthcare system. Many people can get healthcare insurance through
their employer or the national healthcare system. The government system
covers about 70%, and the patient covers the remaining 30%.
The first interferon and ribavirin free therapy that
was approved to treat hepatitis C is the combination of Daklinza
(daclatasvir) and Sunvepra (asunaprevir). In a clinical trial of
Japanese patients with genotype 1b patients treated with the combination
of Daklinza plus Sunvepra the cure rate was 84.7%.
Gilead has submitted a New Drug
Application to Japan’s Pharmaceutical and Medical Devices Agency for
sofosbuvir. Sofosbuvir plus ribavirin for a treatment duration of 12
weeks to treat 153 HCV genotype 2a patients achieved a cure rate of
97%. The study was conducted in Japan
Gilead is conducting a phase 3 study of sofosbuvir plus ledipasvir to treat genotype 1 in Japan.