FGFR Inhibitor Tested in Hard-to-Treat GI Cancer

Milind Javle, MD

Given that few options are available for intrahepatic cholangiocarcinoma (ICC), investigators are excited about a phase III trial of the multikinase inhibitor derazantinib (ARQ 087) as a second-line treatment for patients with inoperable or advanced disease. Current options are particularly limited for patients who experience disease progression after standard-of-care first-line chemotherapy. In the single-arm trial (NCT03230318), derazantinib is being tested in patients who have a genetic aberration in the fibroblast growth factor receptor 2 (FGFR2) gene.

With this oral small-molecule inhibitor, investigators hope to treat what is currently considered an orphan disease. “Ten to 15% of patients with ICC may be effectively targeted with a specific FGFR inhibitor,” said Milind Javle, MD, a professor in the Department of Gastrointestinal Medical Oncology at The University of Texas MD Anderson Cancer Center in Houston. Javle is the principal investigator for the trial.

Among gastrointestinal cancers, FGFR2 fusions occur most commonly in ICC and are believed to be drivers in oncogenesis. Cancer triggered by FGFR2 fusions tends to persist despite FGFR-directed therapy, according to Javle. Also, mutations associated with a poor prognosis, such as KRAS and IDH1, are rarely seen in the presence of an FGFR2 fusion, which makes it important to treat specifically for FGFR2-related cancer. “One interesting factor about FGFR fusions is that the patients are often younger, often women, and have a relatively indolent, slow-growth cholangiocarcinoma compared with the FGFR wild-type,” Javle said. Selective FGFR inhibitors have been very effective in ICC. A study of the FGFR inhibitor BGJ398 showed that patients with FGFR2 genetic fusions responded well, achieving partial responses (PRs) or stable disease (SD).¹

Derazantinib inhibits FGFR kinases. Fibroblast growth factors and their receptors tightly regulate cell proliferation, differentiation, migration, survival, and angiogenesis. In cancer, FGFR genes have been found to be dysregulated by multiple mechanisms, including aberrant expression, mutations, chromosomal rearrangements, and amplifications.² Activation of an FGFR kinase, as with many tyrosine kinases, requires autophosphorylation, a process that the drug inhibits. Additionally, derazantinib binds to the unphosphorylated protein, delaying its activation or phosphorylation.

The phase III trial of derazantinib, which is currently enrolling, will test the agent’s anticancer activity in approximately 100 patients with an FGFR2 fusion (FIGURE). Objective response rate (ORR) is the primary endpoint.

Figure. Derazantinib in FGFR2 Gene Fusion-Positive ICC

Eligible patients will have histologically or cytologically confirmed locally advanced, inoperable, or metastatic ICC with FGFR2 gene fusion status confirmed by next-generation sequencing or fluorescence in situ hybridization testing. Participants must have received at least 1 regimen of prior systemic therapy, with evidence of radiographic progression. Patients who were not able to tolerate prior systemic therapy may also be enrolled.

Participants also cannot have evidence of corneal or retinal disorders. This is because FGFR inhibitors have ocular toxicities, according to Javle, and so patients will undergo ophthalmologic examination before they go on the study and be regularly monitored during the study. In the phase I trial of derazantinib in 80 patients with advanced solid tumors, 67 of whom were evaluable for tumor response, toxicities were manageable and objective responses were achieved. There were 3 confirmed PRs, and 26 patients had a best response of SD. Sixteen patients, including 7 whose tumors were positive for FGFR genetic alterations, received therapy for 16 weeks or longer.³

Results from the phase I/II clinical study of derazantinib in 35 patients with ICC and FGFR2 genetic alterations were presented at the 2017 ASCO Annual Meeting. The data demonstrated a robust response rate and a duration of therapy for these patients well in excess of that reported for second-line chemotherapy. The ORR for patients with FGFR2 fusions was 21%, and the disease control rate was 83%. The best responses were PRs in 6 patients, SD in 22, and progressive disease in 6.4

All patients in the phase I/II study experienced adverse events (AEs), but only 7 had serious AEs. Most observed AEs were grade 1/2, with the most common all-grade AEs including ocular toxicity (blurry vision, conjunctivitis, and dry eye), hyperphosphatemia, nausea, dry mouth, asthenia, and fatigue.⁴ Javle noted that although FGFR inhibitors are a class of drugs that induce hyperphosphatemia, which can lead to ectopic calcification and kidney stones, this AE is much less commonly seen with derazantinib than with other FGFR inhibitors. “That adds to the attractiveness of this agent, because hyperphosphatemia requires a specific management with dietary control, as well as phosphate-binding chelating agents, which do add to the cost of care,” he said.

Javle considers the phase III study for derazantinib is very promising in both its efficacy and the favorable toxicity profile. It is possible that the drug could replace standard chemotherapy in the second-line or later setting, or even replace chemotherapy in the first line, he said.

Screening for genetic mutations will change the face of cancer in general, Javle predicts. “Mutation profiling and next-generation sequencing are extremely promising, particularly in ICC, because it has a large number of actionable mutations,” he said.

Derazantinib is being developed by ArQule, located in Burlington, Massachusetts.

References

1. Javle M, Lowery M, Shroff RT, et al. Phase II study of BGJ398 in patients with FGFR-altered advanced cholangiocarcinoma [published online November 28, 2017]. J Clin Oncol. doi: 10.1200/JCO.2017.75.5009.
2. ArQule. Derazantinib (ARQ 087). ArQule website. arqule.com/pipeline/arq-087/. Accessed December 11, 2017.
3. Papadopoulos KP, El-Rayes BF, Tolcher AW, et al. A phase 1 study of ARQ 087, an oral pan-FGFR inhibitor in patients with advanced solid tumours. Br J Cancer. 2017;117(11):1592-1599. doi: 10.1038/bjc.2017.330.
4. 1. Mazzaferro V, El-Rayes BF, Cotsoglou C, et al. ARQ 087, an oral pan-fibroblast growth factor receptor (FGFR) inhibitor, in patients (pts) with advanced intrahepatic cholangiocarcinoma (iCCA) with FGFR2 genetic aberrations. J Clin Oncol. 2017;35(suppl; abstr 4017). ascopubs.org/doi/abs/10.1200/JCO.2017.35.15_suppl.4017.