Drug development refers to the entire process from the discovery of a potential active ingredient to marketing authorization and post-marketing surveillance. It encompasses preclinical research, Phase I to III clinical trials, the regulatory approval process, and post-market pharmacovigilance activities. The complete development cycle takes an average of 10 to 15 years and costs several billion euros depending on the therapeutic area—making drug development one of the most capital-intensive innovation processes of all.
Preclinical Phase
Drug development begins with drug discovery: lead structures are identified and optimized through target identification, high-throughput screening (HTS), structure-activity relationship analyses, and computer-aided modeling (in silico). During the preclinical phase, efficacy, pharmacokinetics, and toxicity are systematically investigated in animal models. In accordance with ICH S guidelines, toxicity studies—including genotoxicity, reproductive toxicity, and carcinogenicity studies—must be completed before clinical trials in humans can begin. The result of the preclinical phase is the Investigational New Drug (IND) dossier (FDA) or the IMPD (Investigational Medicinal Product Dossier) for EU regulatory approval.
Clinical Phases I to III
Clinical development is structured into three classic phases, each pursuing different objectives. Phase I (First-in-Human) tests safety, tolerability, and pharmacokinetics in small groups of healthy volunteers or patients. Phase II investigates efficacy and optimal dosing in the target population—frequently designed as a proof-of-concept study. Phase III provides controlled evidence of efficacy in a larger, representative patient population and forms the basis for marketing authorization. In recent years, adaptive study designs, basket and umbrella trials, and platform studies have supplemented the classic phase structure or partially replaced it in certain areas, such as oncology or rare diseases.
Regulatory Approval Process
At the end of clinical development stands the submission of the marketing authorization application. In the EU, this is done via the Centralised Procedure (CP) at the EMA for innovative medicinal products, as well as via decentralized or national procedures for generics and certain product classes. The marketing authorization application—the Common Technical Document (CTD)—comprises modules on quality, preclinical and clinical safety, and efficacy. The approval process in the EU regularly takes 210 days but can be shortened through expedited procedures (e.g., PRIME designation, Conditional Marketing Authorisation). Following approval, the post-authorization phase follows with ongoing pharmacovigilance and, if necessary, Phase IV studies.
The costs of drug development have increased massively in recent decades—high attrition rates in Phase II and III are the primary drivers. Improved biomarker strategies, better patient selection through precision medicine approaches, and earlier proof-of-concept decisions are intended to increase the success rate of clinical trials and reduce overall development costs. For CROs, this development means a growing demand for biomarker management, companion diagnostic integration, and the statistical planning of adaptive study designs—competencies that are becoming a differentiating competitive advantage in the market for clinical research services.
Innovations in Drug Development
Modern technologies are fundamentally changing drug development. Artificial intelligence and machine learning accelerate target identification and lead optimization while reducing the number of required animal experiments through in silico modeling. Decentralized Clinical Trials (DCTs) enable location-independent study participation through eConsent, digital endpoints, and remote monitoring. Biologics, gene and cell therapies, and personalized medicine present regulatory authorities with new assessment challenges and have led to the development of adaptive pathways such as the EMA Rolling Review. These developments increase the importance of close collaboration between sponsor, CRO, and regulatory authorities from the very beginning of development.
In addition to the technical and regulatory dimensions, drug development also has an increasingly patient-centered focus. Patient engagement—the early involvement of patient representatives in study design, endpoint selection, and benefit-risk assessments—is now an important quality requirement for many authorities and HTA bodies. Patient-relevant endpoints such as quality of life, patient-reported outcomes (PROs), and functional status are gaining importance over purely clinical-technical parameters. Sponsors who integrate this approach into their development strategy at an early stage improve both the chances of approval and the subsequent HTA assessment.
The collaboration between sponsor and CRO is particularly close in drug development. CROs often take over the entire clinical study program—from protocol development and ethics and regulatory submissions to monitoring, data management, and statistics. In this context, a trend toward strategic alliance models has developed, in which the CRO and sponsor collaborate on a long-term basis across multiple studies, which increases knowledge transfer efficiency and reduces costs.
Frequently Asked Questions
How long does drug development take on average?
On average, 10 to 15 years pass from drug discovery to marketing authorization. Clinical development alone typically takes 6 to 10 years. Accelerated procedures such as Fast Track, Breakthrough Therapy (FDA), or PRIME (EMA) can significantly shorten the process for medicinal products with high medical need.
What is the difference between a biologic and a chemically synthesized drug?
Chemically synthesized drugs (small molecules) are produced through chemical synthesis and have a clearly defined molecular structure. Biologics—such as monoclonal antibodies, growth factors, or gene therapies—are produced in living systems and are structurally more complex. This complexity places higher demands on manufacturing quality (GMP), analytics, and regulatory assessment, particularly regarding immunogenicity and biosimilar development.
What is a Phase IV clinical trial and when is it used?
Phase IV trials are clinical studies conducted after a drug has received marketing authorization. They serve to investigate long-term safety (Post-Authorisation Safety Studies, PASS), effectiveness under routine conditions, the evaluation of new indications, or the generation of data for HTA procedures. Phase IV studies can be conducted voluntarily by the sponsor or as a condition imposed by the regulatory authority.