A Phase I Study of FOLFIRINOX Plus IPI-926 for Advanced Pancreatic Adenocarcinoma
Pancreatic adenocarcinoma (PDAC) represents the fourth leading cause of cancer-related
mortality in the United States, with an estimated 36,800 deaths attributable to PDAC in
2010.(1) Over 90% of patients have inoperable disease at presentation, at which point
systemic therapy becomes the primary form of treatment. Single agent gemcitabine became the
standard of care for advanced pancreatic cancer a decade ago since demonstrating improved
survival when compared with fluorouracil. Since then, a number of phase III trials have
evaluated the benefit of adding additional cytotoxic or targeted agents to gemcitabine, as
shown in the table below. The PA.3 trial(2), which led to the approval of erlotinib in
advanced pancreatic cancer, was a landmark study in that it represented the first positive
phase III study of a combination regimen for this disease indication; however, while
erlotinib represents both an important proof of principle and a welcome addition to our
therapeutic armamentarium, it has failed to gain significant traction in this disease, as
many in the oncology community consider the marginal absolute improvement in median overall
survival to be of questionable clinical significance.
FOLFIRINOX: A new standard of care for advanced PDAC? At the 2010 American Society of
Clinical Oncology Annual Meeting (ASCO), a French cooperative group presented results of a
potentially practice-changing phase III clinical trial (PRODIGE 4/ACCORD 11).(18) In this
study, 342 patients with previously untreated metastatic pancreatic cancer were randomized
to receive either gemcitabine monotherapy or the combination of biweekly infusional
5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) (ref). The
investigators reported statistically significant improvements for the FOLFIRINOX arm in the
primary endpoint, overall survival (median of 11.1 months vs 6.8 months, P < .0001); as well
as 1-year survival rate (48.4% vs. 20.6%), median progression-free survival (6.4 vs. 3.3
months; P < .0001), and objective response rate (CR+PR, 31.6% vs. 9.4%; P = .0001)). Not
surprisingly, the more complex FOLFIRINOX regimen was associated with higher rates of grade
3/4 toxicities, including neutropenia (45.7% vs 18.7%), febrile neutropenia (5.4% vs. 0.6%),
fatigue (23.2% vs. 14.2%), and diarrhea (12.7% vs. 1.2%). Notably, while primary prophylaxis
with growth factor support was not mandated in this trial, 42.5% of patients did ultimately
receive such support. Moreover, most patients enrolled in this trial had non-pancreatic head
tumors (approximately 64%) which is the opposite distribution of what one might expect in a
representative pancreatic cancer population. Thus, it is conceivable that the FOLFIRINOX
regimen, with its high rates of neutropenia, may lead to unacceptable rates of infectious
complications (eg, ascending cholangitis and biliary sepsis), in patients with pancreatic
head tumors with indwelling endobiliary stents.
Nevertheless, this strikingly positive survival benefit, with a median overall survival
approaching one year in a purely metastatic cohort, has never before been observed in any
previous study, which raises the question of whether FOLFIRINOX should become the newly
adopted standard of care, at least in patients with preserved performance status (patients
on this trial were required to have an ECOG performance score of 0-1).
HEDGEHOG SIGNALING The Hedgehog(19) signaling pathway is important for normal mammalian
embryonic development and for adult tissue remodeling. Recent reports have demonstrated that
aberrant activation of the Hh pathway is associated with many types of cancer, including
basal cell carcinoma (BCC), medulloblastoma, pancreatic adenocarcinomas, small-cell lung
cancer (SCLC), metastatic prostate cancer, glioma, breast cancer, hepatocellular cancer, and
hematologic malignancies. High levels of Hh pathway activation, either through mutation of
pathway components or through constitutive expression of Hh pathway genes, appear to be
involved in both the initiation of cancer and tumor cell survival, as well as tumor growth
and metastasis. Given the therapeutic potential of Hh pathway inhibition in cancer, Infinity
has developed IPI-926, a potent and specific antagonist of the Hh pathway that binds
Smoothened (Smo), a key signaling transmembrane protein in this pathway, thereby diminishing
downstream promoters of cellular proliferation.
Pancreatic adenocarcinomas are an ideal tumor class in which to evaluate the activity of a
Hh pathway inhibitor, as multiple lines of evidence support a role for Hedgehog signaling in
pancreatic tumorigenesis:
- Aberrant expression of Sonic hedgehog (SHH) and its associated signaling components
(patched (PTC) and smoothened (SMO)) are frequently found in pancreatic cancer
specimens.(20-27)
- Pharmacologic inhibition of hedgehog signaling produces antitumor effects in pancreatic
cancer cell lines27 and orthotopic xenograft models.(28,29) Studies involving global
sequencing analysis have identified this pathway as one of the central elements
undergoing transformation in nearly all pancreatic cancers.(21)
- Hedgehog signaling may play an important role in maintenance of pancreatic cancer stem
cells.(30-32)
- The dense desmoplastic mesenchymal network that constitutes the stroma of pancreatic
adenocarcinomas coupled with poor vascularity may present a major challenge to
effective delivery of intravenous chemotherapy to the bulk of pancreatic tumor cell
burden. Recent evidence in a genetically engineered mouse model of pancreatic cancer
demonstrated that IPI-926 can deplete tumor-associated stromal tissue and increase
intratumoral mean vessel density, resulting in enhanced delivery of concurrently
administered systemic agents such as gemcitabine, decreased tumor burden, and prolonged
survival.(33)
Interventional
Allocation: Non-Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment
The maximum tolerated dose (MTD) for FOLFIRINOX plus IPI-926 in patients with advanced pancreatic cancer.
Ongoing evaluation through sequential dose cohorts; evaluations at 2-week intervals up to one year.
Yes
Andrew Ko, M.D.
Principal Investigator
University of California, San Francisco
United States: Institutional Review Board
CC#11455
NCT01383538
August 2011
December 2013
Name | Location |
---|---|
University of Wisconsin Comprehensive Cancer Center | Madison, Wisconsin 53792 |
UCSF Helen Diller Family Comprehensive Cancer Center | San Francisco, California 94115 |
University of Chicago Comprehensive Cancer Center | Chicago, Illinois 60637-1470 |