What’s a Phase 1 Cancer Drug Trial?

Traditionally, early-phase clinical trials have been used to determine basic information about how a newly developed drug affects human beings. After animal studies have been completed, a drug moves into phase 1 trials with people—generally healthy volunteers. The phase 1 studies are designed to determine how the new drug is absorbed, metabolized, and excreted in the human body and what side effects are associated with the drug. Drugs that pass phase 1 move on to phase 2 studies that test the efficacy of the medication.

Trials of cancer drugs are a bit different. Traditional phase 1 cancer drug trials focused on dose optimization and toxicities and were broadly aimed across cancer types in the hope of achieving a response or signal. In these early studies, no real effort was made to pair patients with best therapies. Consequently, few patients responded.

However, early-phase cancer trials have evolved. Next-generation precision medicine techniques based on molecular profiling and genomic analysis are now used to match patients to the most appropriate therapies. Many current phase 1 cancer trials actually function as phase 2 studies because efficacy is an endpoint. The result? Response rates closer to 20% with a disease control rate >30% are routinely observed for otherwise treatment-refractory patients.

A great deal of behind-the-scenes work is required to obtain these improved outcomes, and an article in the fall issue of Ochsner Journal discusses the many challenges of establishing and maintaining an early-phase clinical trials program: the regulatory requirements, the difficulty of identifying patients with the exact mutation that matches a targeted drug, the complexity of the studies, and the intense clinical monitoring required during the trial.

It’s a fascinating read with a strong message of hope: these targeted therapies are having a very real and positive impact on patients who in the recent past would have had no treatment alternatives.

Ochsner Journal is a quarterly, peer-reviewed medical journal that is fully searchable at PubMed. To subscribe to the Journal and receive notification each quarter when an issue is published, subscribe to the electronic table of contents by completing this brief form.