美国生物制品中孤儿药的研发现状 及对中国孤儿药研发策略的思考

过去30 年, 美国在全球第一部《孤儿药法案》推动和相关政策法规引导下,生物科技飞速发展,尤其在孤儿药研发领域,成果卓著。 对这30 年来美国FDA 批准的生物制品中孤儿药产品作一解析,回顾美国对生物制品中孤儿药的研发策略,介绍孤儿药开发的新型商业 模式,同时反思中国孤儿药研发策略。     

罕见病治疗用药的发展态势分析

<正>长期以来,罕见病的治疗用药(孤儿药)的开发并未受到重视,因此21世纪以来各国通过罕见病治疗用药物相关法规的建立,来刺激孤儿药的开发。与此同时,在普通疾病的用药开发陷入困难之际,世界各大制药企业也将目光投向了孤儿药的研发。文章就孤儿药的开发现状和部分孤儿药的市场前景进行了分析。     

“首届中国孤儿药研发论坛”专家观点

对2015 年4 月25 日召开的“首届中国孤儿药研发论坛”的专家报告内容进行归纳总结,旨在为从事罕见病诊断和孤儿药研发工 作的人士提供信息参考。报告内容涉及国内外孤儿药研发现状和前景、中国孤儿药政策和审评状况、罕见病诊断以及中国孤儿药研发的机 会等。     

“首届中国孤儿药研发论坛”专家观点（续）

对 2015 年 4 月 25 日召开的“首届中国孤儿药研发论坛”与会专家对话内容进行归纳总结,旨在为从事罕见病诊断和孤儿药研发工作的人士提供信息参考。来自产、学、研领域的专家从研发、临床、审评、投资、媒体等角度探讨了中国孤儿药研发策略。     

日本制药企业加大对孤儿药的投入

制药企业纷纷表示,对孤儿药的投入不够。然而,在过去的几年里,出现了以罕见疾病治疗药作为研发重点的制药企业。日本政府也推出多项举措支持孤儿药尽快实用化。     

罕见病基因治疗与孤儿药

孤儿药因面向的罕见病患者群小、市场需求低、研发成本高、缺乏政策支持等,其发展面临困境。随着精准医疗概念的提出,基 因治疗因能够从根本出发,给患者提供 “一劳永逸”的治疗,备受关注。基因治疗以单基因罕见病的治疗作为极佳切入点,为孤儿药的 研发带来了新的希望。概述基因治疗针对的疾病对象、实施策略和属性以及基因药物的结构及基因治疗的载体,以血友病的基因治疗为 例回顾罕见病基因治疗的发展,并分析罕见病基因治疗药物研发现状。     

各国孤儿药政策对比分析

据统计，医学上明确诊断的罕见病有5 000~8 000 种。虽然因患病人数少而得名罕见病，但考虑到疾病种类之多，罕见病仍是 各国不可忽视的公共卫生挑战。协助和激励医疗行业开发治疗罕见病的孤儿药，是各国政府一项重要的公共卫生政策。重点介绍了美国、 日本和欧盟的孤儿药立法，激励政策以及对病患、医药行业的积极影响。     

“孤儿药”激励机制亟待设立

在治疗罕见病的"孤儿药"的研发领域,一直活跃着许多新兴的中小型生物技术企业。而现在,随着越来越多的大型制药企业将研发重心转向孤儿药,这个领域呈现出群雄逐鹿的态势(见本期"产经"栏目)。对于我国的制药行业来说,这个领域也充满的着机会,因为在一定意义上来说,大家都处于同一起跑线上。但相比于发达国家日益健全的针对"孤儿药"研发的法规,我国在相关政策和立法上还处于起步阶段,如果不尽快推进相关法规和激励机制的设立,那必将制约中国     

罕见疾病及孤儿药物研究现状及进展

文中简述了罕见疾病的定义、发病原因、分类,总结了国内外罕见疾病研究和孤儿药物研发的现状,分析了生物技术的研究手段在罕见疾病药物研发方面的应用,进一步阐述了罕见疾病研究和孤儿药物开发的必要性和紧迫性,对推动科学技术的进步和人类健康事业的发展具有深远的意义。     

我国亟需推动罕见病用药的研发和产业化

<正>罕见病一般指患病人数不足总人口1‰的疾病,全球已知的罕见病约有7 000种。用于罕见病治疗的"孤儿药"已经成为全球医药产业的重要分支,预计到2020年将占到全球处方药销售额的19.1%。我国罕见病诊疗和孤儿药研发尚处于起步阶段,推动相关研究具有重要的社会、经济意义和学术价值。首先,我国罕见病患者的绝对数量多,利用质优价廉的自主药品代替价格昂贵的进口产品,可大幅降低患者负担,并创造巨大     

Access to Orphan Drugs: A Comprehensive Review of Legislations,Regulations and Policies in 35 Countries

ObjectiveTo review existing regulations and policies utilised by countries to enable patient access to orphan drugs.MethodsA review of the literature (1998 to 2014) was performed to identify relevant, peer-reviewed articles. Using content analysis, we synthesised regulations and policies for access to orphan drugs by type and by country.ResultsFifty seven articles and 35 countries were included in this review. Six broad categories of regulation and policy instruments were identified: national orphan drug policies, orphan drug designation, marketing authorization, incentives, marketing exclusivity, and pricing and reimbursement. The availability of orphan drugs depends on individual country’s legislation and regulations including national orphan drug policies, orphan drug designation, marketing authorization, marketing exclusivity and incentives such as tax credits to ensure research, development and marketing. The majority of countries (27/35) had in place orphan drug legislation. Access to orphan drugs depends on individual country’s pricing and reimbursement policies, which varied widely between countries. High prices and insufficient evidence often limit orphan drugs from meeting the traditional health technology assessment criteria, especially cost-effectiveness, which may influence access.ConclusionsOverall many countries have implemented a combination of legislations, regulations and policies for orphan drugs in the last two decades. While these may enable the availability and access to orphan drugs, there are critical differences between countries in terms of range and types of legislations, regulations and policies implemented. Importantly, China and India, two of the largest countries by population size, both lack national legislation for orphan medicines and rare diseases, which could have substantial negative impacts on their patient populations with rare diseases.     

Drug repositioning for orphan diseases

The need and opportunity to discover therapeutics for rare or orphan diseases are enormous. Due to limited prevalence and/or commercial potential, of the approximately 6000 orphan diseases (defined by the FDA Orphan Drug Act as <200 000 US prevalence), only a small fraction (5%) is of interest to the biopharmaceutical industry. The fact that drug development is complicated, time-consuming and expensive with extremely low success rates only adds to the low rate of therapeutics available for orphan diseases. An alternative and efficient strategy to boost the discovery of orphan disease therapeutics is to find connections between an existing drug product and orphan disease. Drug Repositioning or Drug Repurposing--finding a new indication for a drug--is one way to maximize the potential of a drug. The advantages of this approach are manifold, but rational drug repositioning for orphan diseases is not trivial and poses several formidable challenges--pharmacologically and computationally. Most of the repositioned drugs currently in the market are the result of serendipity. One reason the connection between drug candidates and their potential new applications are not identified in an earlier or more systematic fashion is that the underlying mechanism 'connecting' them is either very intricate and unknown or indirect or dispersed and buried in an ever-increasing sea of information, much of which is emerging only recently and therefore is not well organized. In this study, we will review some of these issues and the current methodologies adopted or proposed to overcome them and translate chemical and biological discoveries into safe and effective orphan disease therapeutics.     

eRepo-ORP: Exploring the Opportunity Space to Combat Orphan Diseases with Existing Drugs

About 7000 rare, or orphan, diseases affect more than 350 million people worldwide. Although these conditions collectively pose significant health care problems, drug companies seldom develop drugs for orphan diseases due to extremely limited individual markets. Consequently, developing new treatments for often life-threatening orphan diseases is primarily contingent on financial incentives from governments, special research grants, and private philanthropy. Computer-aided drug repositioning is a cheaper and faster alternative to traditional drug discovery offering a promising venue for orphan drug research. Here, we present eRepo-ORP, a comprehensive resource constructed by a large-scale repositioning of existing drugs to orphan diseases with a collection of structural bioinformatics tools, including eThread, eFindSite, and eMatchSite. Specifically, a systematic exploration of 320,856 possible links between known drugs in DrugBank and orphan proteins obtained from Orphanet reveals as many as 18,145 candidates for repurposing. In order to illustrate how potential therapeutics for rare diseases can be identified with eRepo-ORP, we discuss the repositioning of a kinase inhibitor for Ras-associated autoimmune leukoproliferative disease. The eRepo-ORP data set is available through the Open Science Framework at https://osf.io/qdjup/.     

GPCRs heterodimerization: a new way towards the discovery of function for the orphan receptors?

G protein-coupled receptors (GPCRs), also called seven transmembrane domain (7TM) proteins, represent the largest family of cell surface receptors. GPCRs control a variety of physiological processes, are involved in multiple diseases and are major drug targets. Despite a vast effort of academic and industrial research, more than one hundred receptors remain orphans. These orphan GPCRs offer a great potential for drug discovery, as almost 60% of currently prescribed drugs target GPCRs. Deorphenization strategies have concentrated mainly on the identification of the natural ligands of these proteins. Recent advances have shown that orphan GPCRs, similar to orphan nuclear receptors, can regulate the function of non-orphan receptors by heterodimerization. These findings not only help to better understand the extraordinary diversity of GPCRs, but also open new perspectives for the identification of the function of these orphan receptors that hold great therapeutic potential.     

Database identifies FDA-approved drugs with potential to be repurposed for treatment of orphan diseases

Facing substantial obstacles to developing new therapies for rare diseases, some sponsors are looking to 'repurpose' drugs already approved for other conditions and use those therapies to treat rare diseases. In an effort to facilitate such repurposing and speed the delivery of new therapies to people who need them, we have established a new resource, the Rare Disease Repurposing Database (RDRD). The advantages of repurposed compounds include their demonstrated efficacy (in some clinical contexts), their observed toxicity profiles and their clearly described manufacturing controls. To create the RDRD, we matched the US Food and Drug Administration (FDA) orphan designation database to FDA drug and biological product approval lists. The RDRD lists 236 products that have received orphan status designation--that is, were found to be 'promising' for the treatment of a rare disease--and though not yet approved for marketing for that rare disease, they are already approved for marketing to treat some other disease or condition. The RDRD contains three tables: Orphan-designated products with at least one marketing approval for a common disease indication (N = 109); orphan-designated products with at least one marketing approval for a rare disease indication (N = 76); and orphan-designated products with marketing approvals for both common and rare disease indications (N = 51). While the data included in the database is a re-configuration/cross-indexing of information already released by the FDA, it offers sponsors a new tool for finding special opportunities to develop niche therapies for rare disease patients.     

Funding innovation for treatment for rare diseases: adopting a cost-based yardstick approach

Background

Manufacturers justify the high prices for orphan drugs on the basis that the associated R&D costs must be spread over few patients. The proliferation of these drugs in the last three decades, combined with high prices commonly in excess of $100,000 per patient per year are placing a substantial strain on the budgets of drug plans in many countries. Do insurers spend a growing portion of their budgets on small patient populations, or leave vulnerable patients without coverage for valuable treatments? We suggest that a third option is present in the form of a cost-based regulatory mechanism.

Methods

This article explores the use of a cost-based price control mechanism for orphan drugs, adapted from the standard models applied in utilities regulation.

Results and conclusions

A rate-of-return style model, employing yardsticked cost allocations and a modified two-stage rate of return calculation could be effective in setting a new standard for orphan drugs pricing. This type of cost-based pricing would limit the costs faced by insurers while continuing to provide an efficient incentive for new drug development.

     

Molecular Approaches to Receptors as Targets for Drug Discovery

Abstract

The cloning of a great number of receptors and channels has revealed that many of these targets for drug discovery can be grouped into superfamilies based on sequence and structural similarities. This review presents an overview of how molecular biological approaches have revealed a plethora of receptor subtypes, led to new definitions of subtypes and isoforms, and played a role in the development of highly selective drugs. Moreover, the diversity of subtypes has molded current views of the structure and function of receptor families. Practical difficulties and limitations inherent in the characterization of the ligand binding and signaling properties of expressed recombinant receptors are discussed. The importance of evaluating drug-receptor interactions that differ with temporally transient and distinct receptor conformational states is emphasized. Structural motifs and signal transduction features are presented for the following major receptor superfamilies: ligand-gated ion channel, voltage-dependent ion channel, G-protein coupled, receptor tyrosine-kinase, receptor protein tyrosine-phosphatase, cytokine and nuclear hormone. In addition, a prototypic receptor is analyzed to illustrate functional properties of a given family. The review concludes with a discussion of future directions in receptor research that will impact drug discovery, with a specific focus on orphan receptors as targets for drug discovery. Methods for classifying orphan receptors based upon homologies with members of existing superfamilies are presented together with molecular approaches to the greater challenge of defining their physiological roles. Besides revealing new orphan receptors, the human genome sequencing project will result in the identification of an abundance of novel receptors that will be molecular targets for the development of highly selective drugs. These findings will spur the discovery and development of an exciting new generation of receptor-subtype specific drugs with enhanced therapeutic specificity.