The journey of a cancer drug from laboratory discovery to FDA approval is long, expensive, and uncertain. On average, it takes 10-15 years and costs over $1 billion to bring a new cancer drug to market. Of every 10,000 compounds that enter preclinical testing, only about 1 ultimately receives FDA approval. Understanding this process provides essential context for interpreting the clinical trial data presented throughout PipelineEvidence.
Preclinical Development
Before any drug reaches a human patient, it undergoes extensive preclinical testing. This begins with in vitro studies in cancer cell lines to identify compounds that kill cancer cells or block critical growth pathways. Promising compounds advance to in vivo studies in animal models to assess efficacy, pharmacokinetics (how the body processes the drug), and toxicity. Only compounds with a favorable preclinical profile proceed to human testing through an Investigational New Drug (IND) application to the FDA.
Clinical Trial Phases
Phase 1 trials prioritize safety. Typically enrolling 15-30 patients with various advanced cancers, they use dose escalation designs (often the traditional 3+3 design or newer Bayesian methods) to identify the maximum tolerated dose and recommended phase 2 dose. Phase 2 trials evaluate efficacy in a specific tumor type, typically enrolling 30-100 patients. Response rate is the usual primary endpoint. Phase 2 expansion cohorts may test the drug across multiple tumor types.
Phase 3 trials are the pivotal studies that determine whether a new drug changes standard of care. These are randomized controlled trials comparing the experimental treatment to the current standard. They typically enroll hundreds to thousands of patients and use clinically meaningful endpoints (overall survival or progression-free survival). Positive phase 3 results form the basis for New Drug Application (NDA) submission to the FDA.
FDA Approval Pathways
The FDA offers several pathways for cancer drug approval. Regular approval requires substantial evidence of clinical benefit, typically from randomized phase 3 trials. Accelerated approval permits earlier approval based on surrogate endpoints (like response rate) when a drug treats a serious condition with unmet need. Post-marketing confirmatory trials are required to verify clinical benefit.
Breakthrough therapy designation expedites development for drugs showing substantial improvement over existing treatments. Priority review shortens the FDA review timeline from 12 months to 8 months. Fast track designation facilitates ongoing communication with the FDA during development. Many cancer drugs receive multiple expedited designations simultaneously.
The Current Landscape
The pace of cancer drug approvals has accelerated dramatically. In 2023 alone, the FDA approved over 15 new cancer drugs or new indications for existing drugs. This reflects both scientific advances (better understanding of tumor biology, new drug modalities like ADCs and bispecific antibodies) and regulatory innovations (accelerated approval, tumor-agnostic approvals). PipelineEvidence tracks both approved therapies and active clinical trials across 50 tumor types, providing a comprehensive view of the evolving treatment landscape.