SAN DIEGO –
The goal is “to better identify and characterize optimized doses” in early stages of research and move away from the default of the traditional maximum tolerated dose strategy, hematologist-oncologist Marc R. Theoret, MD, deputy director of the FDA’s Oncology Center of Excellence, said in a presentation at the 2023 Society for Immunotherapy of Cancer annual meeting.
Earlier this year, the FDA released a draft guidance regarding the changes it hopes to see. The agency supported randomized, parallel dose-response trials when feasible, and “strong rationale for choice of dosage should be provided before initiating a registration trial(s) to support a subsequent indication and usage.”
The goal of controlling toxicity is “very highly important” in hematology research since blood cancer drugs can cause significant adverse effects in areas such as the lungs and heart, said Cecilia Yeung, MD, who led the SITC session about Project Optimus. Dr. Yeung is a clinical pathologist who works on investigational trials at Fred Hutchinson Cancer Research Center in Seattle.
In an interview, Dr. Yeung, who has a subspecialty in hematopathology, explained why the foundations of cancer research are changing and what hematologist-oncologists can expect to see on the horizon.
Q: Project Optimus aims to move beyond the traditional dose-escalation approach to the development of cancer drugs. How does that strategy work?
Dr. Yeung: Prior to Project Optimus, they’d use a 3+3 strategy in phase 1 trials: They’d give a dose to three fairly healthy patients, then they’d go up by escalating doses in more patients. They’d keep going up until two-thirds of patients at a specific dose suffered from bad side effects, then they’d back off to the last dose.
Q: This approach, which aims to identify the “maximum tolerated dose,” seemed to work well over decades of research into chemotherapy drugs. But worries arose as targeted therapies appeared in oncology areas such as blood cancer. Why did things change?
Dr. Yeung: With 3+3, you could tell pretty quickly how toxic chemotherapy was. But in targeted therapy, we were finding that these studies are not representative of actual toxicity. You’re not treating these patients for a very long time in phase 1, while patients on targeted therapy may be on these drugs for years. Concerns actually started with the first targeted drugs to treat leukemias and lymphomas. They were shown to have unexpected toxicity. A 2016 study found that drug developers had to reduce the original phase 1 dose in 45% of phase 3 trials [of small molecule and monoclonal antibody targeted agents] approved by the FDA over 12 years because of toxicity.
Q: What is FDA’s goal for Project Optimus?
Dr. Yeung: They want to have a second piece, to balance that maximum tolerated dose with a safe and tolerable dose for most people.
Q: What kind of resistance is the FDA getting from drug companies?
Dr. Yeung: The FDA makes a good argument that the system wasn’t working. But drug companies say this will drive up the cost of clinical trials and won’t allow them to treat patients with the maximal doses they could give them. I see arguments from both sides. There has to be a balance between the two.