VIREAD works by interfering with the normal working of an enzyme (HBV DNA polymerase) that is essential for the hepatitis B virus (HBV) to reproduce itself. VIREAD may help lower the amount of hepatitis B virus in your body by lowering the ability of the virus to multiply and infect new liver cells.1
VIREAD has also been used since 2001 as a treatment for Human Immunodeficiency Virus (HIV) infection in adults age 18 years and older. VIREAD is always used in combination with other anti-HIV-1 medicines to treat people with HIV-1 infection.1
1 INDICATIONS AND USAGE
1.1 HIV-1 Infection
VIREAOCI is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in adults.
The following points should be considered when initiating therapy with VIREAO for the treatment of HIV-1 infection:
· VIREAO should not be used in combination with RUVAOACI or ATRIPLACI ).
1.2 Chronic Hepatitis B
VIREAO is indicated for the treatment of chronic hepatitis B in adults. The following points should be considered when initiating therapy with VIREAO for the treatment of HBV infection:
. This indication is based primarily on data from treatment of nucleoside-treatment­naïve subjects and a smaller number of subjects who had previously received lamivudine or adefovir. Subjects were adults with HBeAg-positive and HBeAg
negative chronic hepatitis B with compensated liver disease
. The numbers of subjects in clinical trials who had lamivudine- or adefovirassociated substitutions at baseline were too small to reach conclusions of efficacy , Clinical Effcacy in Patients with Chronic Hepatitis B。
2 DOSAGE AND ADMINISTRATION
2.1 Recommended Dose
For the treatment of HIV-1 or chronic hepatitis B: The dose of VIREAD is 300 mg once daily taken orally, without regard to food. In the treatment of chronic hepatitis B, the optimal duration of treatment is unknown.
2.2 Dose Adjustment for Renal Impairment
Significantly increased drug exposures occurred when VIREAD was administered to subjects with moderate to severe renal impairment 。
Therefore, the dosing interval of VIREAD should be adjusted in patients with baseline creatinine clearance ..50 mL/min using the recommendations in Table 1. These dosing interval recommendations are based on modeling of single-dose pharmacokinetic data in non-HIV and non-HBV infected subjects with varying degrees of renal impairment,
including end-stage renal disease requiring hemodialysis. The safety and effectiveness of these dosing interval adjustment recommendations have not been clinically evaluated
in patients with moderate or severe renal impairment, therefore clinical response to treatment and renal function should be closely monitored in these patients .
No dose adjustment is necessary for patients with mild renal impairment (creatinine clearance 50-80 mL/min). Routine monitoring of calculated creatinine clearance and
serum phosphorus should be performed in patients with mild renal impairment ) .

替诺福韦(Viread)是HIV/HBV复合感染的治疗选择
在美国第１２届逆转录病毒和机会感染会议上，美国学者报告，他们进行的一项有关替诺福韦（ｔｅｎｏｆｏｖｉｒ）与阿德福韦（ａｄｅｆｏｖｉｒ）安全性临床对照研究显示，替诺福韦可安全有效地降低ＨＩＶ感染病人的乙型肝炎病毒（ＨＢＶ）水平。
该研究的领导者Ｐｅｔｅｒｓ医师解释说，这是替诺福韦对ＨＩＶ／ＨＢＶ复合感染病人治疗有效的首次随机对照研究。他说，在ＨＩＶ感染者中，有２０％的人合并乙型肝炎。
无论在美国还是在全世界，复合感染都是一个重要问题。
Ｐｅｔｅｒｓ和ＡＩＤＳ临床试验组Ａ５１２７的研究人员，对５２例应用稳定联合抗逆转录病毒治疗的合并ＨＢＶ感染的病人进行了研究。基线时，有７５％的病人ＨＩＶＲＮＡ低于５０拷贝／ｍＬ，９８％有代偿性肝病。
这些病人随机进入替诺福韦３００ ｍｇ／ｄ＋安慰剂组，或阿德福韦１０ｍｇ／ｄ＋安慰剂组，疗程９６周。每周进行实验室评估。有８０％的病人服用过拉米夫定。
结果显示，替诺福韦对野生型和拉米夫定抗药型ＨＢＶ均有治疗活性。Ｐｅｔｅｒｓ说，替诺福韦曾被批准用于治疗ＨＩＶ感染，但非ＨＢＶ感染。阿德福韦最近被允许用于ＨＢＶ感染。
分析表明，替诺福韦的疗效不亚于阿德福韦。替诺福韦降低ＨＢＶＤＮＡ的效果实际上优于阿德福韦。４８周后，替诺福韦组病人的ＨＢＶ ＤＮＡ平均ｌｏｇ１０倍加权平均值较基线时降低４．４，阿德福韦组降低３．２１。
两组均有１８例病人的实验室指标异常；均无不良事件发生。虽然两组均有２例死亡，但与治疗用药无关；未发现有肾毒性。
Ｐｅｔｅｒｓ总结认为，替诺福韦是ＨＩＶ／ＨＢＶ复合感染病人的治疗选择。虽然曾有非对照试验资料，但这是证明疗效的首次随机对照研究，它为ＨＩＶ／ＨＢＶ感染病人增加了新的治疗选择。
美国抗HIV药Viread将申报抗肝炎适应症
美国生物制药公司Gilead Sciences（Nasdaq: GILD）于2007年6月25日对外公布说，新的III期临床研究再次证实其抗HIV药Viread对丙型肝炎病毒有疗效。Viread是非核酸类反转录酶抑制剂，2006年获批在美国和欧洲上市。Gilead在今年6月完成了2个III期临床研究，分别针对两种不同亚型的乙型肝炎病毒，都得到了阳性结果。Gilead将于今年第四季度完成在美国和欧洲以乙型肝炎为扩大适应症的上市申请。
Gilead公司3月8日宣布，美国FDA已授予其抗逆转录病毒药物Viread（替诺福韦）和Truvada（恩曲他滨/替诺福韦）传统批准地位。Truvada含有该公司两种抗逆转录药Emtriva（恩曲他滨）和Viread。