In February, the US Food and Drug Administration (FDA) approved irinotecan liposome (Onivyde) as part of a new regimen for first-line metastatic pancreatic adenocarcinoma called NALIRIFOX.
The main difference between NALIRIFOX and a standard go-to regimen for the indication, modified FOLFIRINOX, is that liposomal irinotecan — irinotecan encased in a lipid nanoparticle — is used instead of free irinotecan.
Trial data suggested a better overall response rate, a slight progression-free survival advantage, and potentially fewer adverse events with the liposomal formulation.
The substitution, however, raises the cost of treatment substantially. According to one estimate, a single cycle of FOLFIRINOX costs about $500 at a body surface area of 2 m2, while the equivalent single cycle of NALIRIFOX costs $7800 — over 15-fold more expensive.
While some oncologists have called the NALIRIFOX regimen a potential new standard first-line treatment for metastatic pancreatic adenocarcinoma, others have expressed serious doubts about whether the potential benefits are worth the extra cost.
“I can’t really see a single scenario where I would recommend NALIRIFOX over FOLFIRINOX” Ignacio Garrido-Laguna, MD, PhD, a gastrointestinal oncologist and pancreatic cancer researcher at the University of Utah, Salt Lake City, told this news organization. “Most of us in the academic setting have the same take on this.”
No Head-to-Head Comparison
Instead, the 770-patient NAPOLI 3 trial compared NALIRIFOX — which also includes oxaliplatin, fluorouracil, and leucovorin — with a two-drug regimen, nab-paclitaxel and gemcitabine. In the trial, overall survival and other outcomes were moderately better with NALIRIFOX.
Oncologists have said that the true value of the trial is that it conclusively demonstrates that a four-drug regimen is superior to a two-drug regimen for patients who can tolerate the more intensive therapy.
Eileen M. O’Reilly, MD, the senior investigator on NAPOLI 3, made this point when she presented the phase 3 results at the 2023 ASCO annual meeting.
The trial “answers the question of four drugs versus two” for first-line metastatic pancreatic cancer but “does not address the question of NALIRIFOX versus FOLFIRINOX,” said Dr. O’Reilly, a pancreatic and hepatobiliary oncologist and researcher at Memorial Sloan Kettering Cancer Center in New York City.
Comparing them directly in the study “probably wouldn’t have been in the interest of the sponsor,” said Dr. O’Reilly.
With no head-to-head comparison, oncologists have been comparing NAPOLI 3 results with those from PRODIGE 4, the 2011 trial that won FOLFIRINOX its place as a first-line regimen.
When comparing the trials, median overall survival was exactly the same for the two regimens — 11.1 months. FOLFIRINOX was associated with a slightly higher 1-year survival rate — 48.4% with FOLFIRINOX vs 45.6% with NALIRIFOX.
However, Dr. O’Reilly and her colleagues also highlighted comparisons between the two trials that favored NAPOLI 3.
NAPOLI 3 had no age limit, while PRODIGE subjects were no older than 75 years. Median progression-free survival was 1 month longer among patients receiving NALIRIFOX — 7.4 months vs 6.4 months in PRODIGE — and overall response rates were higher as well — 41.8% in NAPOLI 3 vs 31.6%. Patients receiving NALIRIFOX also had lower rates of grade 3/4 neutropenia (23.8% vs 45.7%, respectively) and peripheral sensory neuropathy (3.5% vs 9.0%, respectively).
The authors explained that the lower rate of neuropathy could be because NALIRIFOX uses a lower dose of oxaliplatin (FOLFIRINOX), at 60 mg/m2 instead of 85 mg/m2.