200萬瓶PrEP是空的比畫嗎？
資料來源：刺胳針愛滋病毒醫學期刊，www.thelancet.com/hiv Vol 6 August 2019；財團法人台灣紅絲帶基金會編譯
如果患者不服用那藥物就不起作用，通常用於愛滋病毒上的熟悉短語，那便是感染者治療時的順從性。但是在美國愛滋病發生率的停滯下降，表明在預防上情況也是相同，使用暴露前預防投藥（PrEP）作為一種公共衛生方法—一種預防措施如果人們沒有去使用它則不具理想的公共衛生效益。所以有人可能會認為美國政府與吉利德公司達成的協議，對20萬有愛滋病感染風險的人捐贈長達11年的PrEP將是值得慶祝的原因，但是愛滋活動家和公共衛生專業人士則不表確定。
當2012年舒發泰（Truvada，tenofovir disoproxil fumarate plus emtricitabine）被批准用作HIV預防，許多人希望它有助於結束愛滋病在美國的流行。但是，自2013年以來，該國每年新發感染人數仍保持相當穩定，在2016年有將近4萬愛滋病毒新感之診斷。估計美國有120萬人有愛滋病毒感染風險，卻只有25萬人左右正在使用PrEP—大多數為受過良好教育、富裕的白種男同性戀者。取得PrEP上的障礙大家都太熟悉了：高價的藥物，每年約需花費2萬美元，然而受益更大的關鍵族群進入醫療照護的機會卻很差，諸如黑人和少數族裔的男男間性行為者、藥癮吸毒者和性工作者。
繼唐納德.川普總統於2019年2月的國情咨文演說之後，他承諾將在美國終結愛滋病毒之流行，政府已經與吉利德一起談判確保每年捐贈200萬瓶PrEP最多達11年。從表面看，這個似乎是一個慷慨的提議，可以幫助沒有保險的人們或無法支付保險部份負擔者取得PrEP。但是，對此消息的回應因受到批評而被強化，認為吉利德的方法是保護專利和價格。國會現在由民主黨政客領導的監督委員會，正在調查導致捐贈之與吉利德的談判，因為有人指責該交易實際上是保護吉利德在市場上的主導地位，當專利到期時阻止學名藥製造商進入市場，並確保新配方Descovy（tenofovir alafenamide and emtricitabine）的市場，如果和當它被批准用作預防投藥時。
舒發泰在許多國家專利都已到期，藉由學名藥價格已降至每年60美元左右，但是在美國的專利將持續到2021年。許多愛滋活動家和美國的公共衛生官員認為，因為舒發泰Truvada作為PrEP的功效在試驗中得到證實，係由美國疾病控制和預防中心所執行因此係由美國納稅人資助，用於預防之部分資金由製藥公司提供，應視為特許權使用費而支付給美國政府 – 有人估計多達10億美元。此外，雖然捐贈似乎很龐大，但雖招募了另外的20萬人到PrEP中，仍然會有超過一半沒有保護而可能受益於PrEP美國人遠離此項照顧。
在另一個最近的發展，美國預防服務工作組（USPSTF），一個在美國提出預防性服務建議的獨立機構給予PrEP最高評級，最後評分為「從愛滋病毒感染高危人群使用PrEP來降低愛滋病毒感染的風險當中，確定會有很大的淨收益」。USPSTF的推薦意味著健康保險團體必須涵蓋PrEP並免費地提供給病人。
為了獲得最大的利益，需要將取得服務之障礙予以最小化。關鍵人群的成員可能會不願意認定自己是處於危險之中，因為罪刑化行為或是因為污名恥辱。保險是已經是一項要求，以及進一步的有關年齡限制或可能需要風險證明資格等均應顧及。
吉利德的捐贈和根據USPSTF的建議對PrEP的提供表面上是積極的步驟，但他們仍然不會在有風險的人數上，以及在PrEP有足夠的人數參與上（在這種已經證實之公共衛生介入措施有足夠參與人數以對應獲取之不公平現象），縮小兩者間的差距。自吉利德於1985年開發舒發泰以來，已經回收了超過它在藥物開發方面上的投資。現在當然是適當的時候，去認知美國納稅人、試驗參與者和政府機構在PrEP的發展上的貢獻以及對公共衛生的義務– 吉利德應該承諾提供所有會受益於PrEP的每個人所需要的劑量或者是開放市場以達到學名藥廠的範圍。 ■刺胳針愛滋病毒
Are 2 million bottles of PrEP an empty gesture?
That a drug does not work if patients do not take it, is a familiar phrase to those working in HIV, usually applied to treatment adherence. But the stalling decline in HIV incidence in the USA shows that the same is true of prevention and the use of pre-exposure prophylaxis (PrEP) as a public health approach—a preventive method will not have the desired public-health benefit if people are not using it. So one might think that the agreement struck between the US Government and Gilead to donate PrEP to 200, 000 people at risk of HIV for up to 11 years would be a cause for celebration, but activists and public-health professionals are not so sure.
When Truvada (tenofovir disoproxil fumarate plus emtricitabine) was approved for use as HIV prevention in 2012, many hoped that it would help to bring an end to the HIV epidemic in the USA. However, since 2013, the annual number of new infections in the country has remained fairly stable, and in 2016 there were almost 40, 000 new diagnoses of HIV infection. Of the estimated 1.2 million people at risk of HIV, only around 250, 000 people are using PrEP—most well educated, affluent, white gay men. The barriers to accessing PrEP are all too familiar: the high price of the drug, which costs around US$20, 000 a year, and poor access to health care for the key populations who would benefit most, such as black and ethnic minority men who have sex with men, drug users, and sex workers.
Following President Donald Trump’s State of the Union Address in February 2019, in which he pledged to end the HIV epidemic in the USA, the government has negotiated with Gilead to secure the donation of 2 million bottles of PrEP each year for up to 11 years. At face value, this seems like a generous offer, that could help people without insurance or unable to afford insurance copays to access PrEP. However, the response to this news has been tempered by criticism of Gilead’s approach to patent protection and pricing. A Congressional Oversight Committee led by Democrat politicians is now investigating the negotiations with Gilead that led to the donation, amid accusations that the deal will, in effect, protect Gilead’s dominance of the market, blocking entry by generic manufacturers when the patent does expire, and securing a market for the new formulation, Descovy (tenofovir alafenamide and emtricitabine), if and when this receives approval for use as prophylaxis.
Truvada is off patent in many countries, with generic drugs bringing prices down to around $60 a year, but the US patent will last until 2021. Many activists and public health officials in the USA argue that because the efficacy of Truvada as PrEP was proven in a trial run by the Centers for Disease Control and Prevention and thereby funded by US taxpayers, some of the money made by the drug company from its use in prevention should be paid as royalties to the US Government—some estimate as much as $1 billion. Moreover, although the donation seems substantial, recruiting an additional 200 000 people to PrEP would still leave far more than half of people in the USA who might benefit from PrEP without protection.
In another recent development, the US Preventive Services Task Force (USPSTF), an independent body that makes recommendations on preventive services in the USA gave PrEP its highest rating, concluding with “high certainty that there is a substantial net benefit from the use of PrEP to reduce the risk of acquisition of HIV infection in persons at high risk of HIV infection”. A recommendation from the USPSTF means that health insurance groups are required to cover PrEP at no charge to patients.
To have the greatest benefit, barriers to access need to be minimal. Members of key populations may be reluctant to identify themselves as being at risk because of criminalised behaviours or stigma. Insurance is already a requirement, and further age restrictions or proof of risk might be required for eligibility.
The donations from Gilead and provision of PrEP under the recommendation of the USPSTF are on the surface positive steps, but they will not close the gap in the number of people at risk and the number of people on PrEP sufficiently to counter the inequity in access to this proven public-health intervention. Since Truvada was developed in 1985, Gilead has more than recouped its investment in the drug development. Surely by now it is time to recognise the contribution of US taxpayers, trial participants, and government agencies to the development of PrEP and the obligation to public health—Gilead should either commit to providing all, the doses of PrEP required for everyone who would benefit or open the market up to a range of generic manufacturers. ■ The Lancet HIV
www.thelancet.com/hiv Vol 6 August 2019