FOLFIRI-bevacizumab as a second-line treatment for advanced biliary tract cancer after gemcitabine-based chemotherapy

Background Advanced biliary tract cancer (BTC) has a poor prognosis. Gemcitabine with platinum chemotherapy was the standard first-line chemotherapeutic regimen until the recent addition of anti-PD-1/PD-L1 antibodies. After disease progression, the only second-line chemotherapy that has demonstrated a survival benefit versus supportive care is FOLFOX (folinic acid, fluorouracil, and oxaliplatin), with a modest benefit. This study aimed to assess the efficacy and safety of second-line FOLFIRI (folinic acid, fluorouracil, and irinotecan) combined with bevacizumab for advanced BTC. Methods This single-center retrospective study enrolled patients with metastatic BTC (intrahepatic cholangiocarcinoma [ICC], extrahepatic cholangiocarcinoma [ECC], or gallbladder carcinoma) that progressed after first-line gemcitabine-based chemotherapy. FOLFIRI-bevacizumab was administered intravenously every 2 weeks [folinic acid 200 mg/m², fluorouracil 400 mg/m² (bolus), fluorouracil 2400 mg/m² (46-h continuous intravenous infusion), irinotecan 180 mg/m², and bevacizumab 5 mg/kg] until unacceptable toxicity, patient refusal, or disease progression. Results Overall, 28 patients received the FOLFIRI-bevacizumab regimen after gemcitabine-based chemotherapy. The median overall survival (OS) was 9.0 months (95% CI 6.4–16.5). The OS rate was 39.3% (95% CI 24.8–62.3) and 10.7% (95% CI 3.7–32.1) at 12- and 24-months respectively. The median progression-free survival (PFS) was 5.2 months (95% CI 3.1–10.2) with FOLFIRI-bevacizumab. The PFS rates at 12 months and 24 months were 17.9% (95% CI 8.19–39.5] and 10.7% (95% CI 3.7–31.2), respectively. The overall response rate (ORR) to FOLFIRI-bevacizumab was 23.1%, with a disease control rate (DCR) of 69.3%. Grade 3-4 adverse events (sAE) were reported in 20 patients (71.4%) treated with FOLFIRI-bevacizumab. Conclusion FOLFIRI-bevacizumab as a second-line treatment for advanced BTC after gemcitabine-based chemotherapy showed efficacy and safety with a promising tumor response rate in this retrospective single-center study.


Introduction
Biliary tract cancer (BTC), which encompasses intrahepatic cholangiocarcinoma (ICC), extrahepatic cholangiocarcinoma (ECC), and gallbladder cancer, has been known to have a poor prognosis (1), with an increase in incidence in high-income countries.To date, surgery is the only curative therapy available for patients with resectable tumors.Liver resection for intrahepatic BTC provides a 5-year overall survival (OS) rate of 25-40% with a median OS of 40 months (2).Notably, most patients are diagnosed with unresectable locally advanced or metastatic BTC and are therefore no longer candidates for this therapeutic option (3).Thus, most patients receive systemic palliative care.Until recently, the first-line standard therapy for metastatic disease was based on a combination of platinum and gemcitabine (4), with cisplatin (5) or oxaliplatin (6-8).In randomized phase III studies, the combination of gemcitabine with cisplatin provided a median OS of 11.7 months (9), numerically better results than oxaliplatin with only 9.5 months of median OS (10).Immunotherapy adjunction with chemotherapy using anti-PD-L1 durvalumab prolongs the survival, with a median OS exceeding 1 year, irrespective of PD-L1 expression (11).Similar results were obtained with pembrolizumab (12).These chemoimmunotherapy protocols are now considered the standard first-line treatment for advanced BTC (13).After disease progression, the ABC-06 trial is the only randomized phase III study that has demonstrated an improvement in OS with FOLFOX versus supportive care (14).Nonetheless, the efficacy of FOLFOX in the second-line setting of metastatic BTC remains modest, with a median progression-free survival (PFS) and median OS of 4.0 and 6.2 months, respectively, and a poor objective response rate of 5%.Because the evidence for irinotecan-based therapies is currently limited, we report the efficacy and safety of the FOLFIRI-bevacizumab combination as a second-line treatment for advanced BTC after gemcitabinebased chemotherapy.

Patients
This single-center retrospective study was conducted at the Georges-Francois Leclerc Center in Dijon, France and included patients with advanced BTC treated between 2009 and 2022.The patients were required to have a histologically confirmed diagnosis of BTC with metastatic or unresectable disease that progressed after first-line gemcitabine-based chemotherapy.Progression was confirmed using thoracic, abdominal, and pelvic computedtomography (CT) scans.Only patients who received FOLFIRIbevacizumab as a second-line treatment in a metastatic setting were included in the analyses.The off-label use of this treatment regimen was validated by a local multidisciplinary staff member.

Treatment regimen
Physical examination, complete blood cell count, and serum chemistry were performed before the initiation of chemotherapy.The FOLFIRI-bevacizumab regimen consisted of bevacizumab injection (5 mg/kg over 90 min) followed by irinotecan (180 mg/ m² i.v. over 90 min) concurrently with folinic acid (200 mg/m² i.v. over 120 min), followed by fluorouracil (400 mg/m² i.v.bolus) and fluorouracil (2400 mg/m² IV infusion over 46 h).This treatment was administered every two weeks.Adverse events were graded according to the Common Terminology Criteria for Adverse Events version 5.0 (CTCAE 5.0).Dose reduction or treatment suspension was based on the grade of adverse events.The treatment was continued until unacceptable toxicity, patient refusal, or disease progression was observed.

Follow-up
Before every FOLFIRI-bevacizumab cycle, a complete physical examination, complete blood cell counts, and serum chemistry were performed.The tumor response was assessed every four cycles or when clinical progression was suspected according to symptoms and clinical examination with thoracic, abdominal, and pelvic CTscans and determined using RECIST version 1.1.If a CT-scan does not provide a proper assessment of the tumor response, magnetic resonance imaging (MRI) can be performed.

Statistical analyses
Progression-free survival (PFS) at the second-line was calculated from the date of FOLFIRI-bevacizumab initiation to the date of progression or death.The overall survival (OS) at second-line treatment was calculated from the date of FOLFIRIbevacizumab initiation to the date of death from any cause or censored at the date of the last follow-up.PFS at first-line treatment was calculated from the date of diagnosis of advanced biliary tract cancer to the date of progression or death, and OS at first-line treatment was calculated from the date of diagnosis to the date of death from any cause or censored at the date of last follow-up.The curves were plotted using a Kaplan-Meier analysis.

Patient characteristics
Overall, 28 patients received FOLFIRI-bevacizumab as a second-line treatment for advanced BTC.A combination of gemcitabine and oxaliplatin (n=20, 71.4%) was the most frequently used first-line regimen (Table 1).The median age was 69.0 years and the majority of patients were male (n=16; 57.1%).Most patients had intrahepatic disease (n=19; 67.9%), with a similar proportion of extrahepatic disease (n=4; 14.3%) and gallbladder disease (n=5; 17.9%).Among the enrolled patients, 16 (57.1%)patients were diagnosed with metastatic disease, 8 (28.6%) patients with unresectable locally advanced disease, and 4 (14.3%)patients with resectable BTC.One patient underwent gallbladder removal for cholecystitis, which turned out to be an adenocarcinoma with peritoneal carcinomatosis.The mean baseline CA19-9 level was 1387.3 kU/L.Notably, 16 (57.1%)patients underwent molecular testing for advanced BTC.The genomic characteristics of these patients are shown in Figure 1.

Discussion
The results of this single-center retrospective study suggest that the combination of FOLFIRI with bevacizumab is an active and safe second-line regimen in patients with advanced BTC who show disease progression with gemcitabine-based chemotherapy.
In this study, the majority of patients received a combination of gemcitabine and oxaliplatin as the first-line systemic treatment for metastatic disease.The first-line standard of care for advanced BTC consists of a gemcitabine-based combination therapy (15), with cisplatin being the preferred option (5).Oxaliplatin remains an alternative to cisplatin when renal function is a concern (13).Nevertheless, the median PFS in the first-line setting observed in this cohort was slightly longer than that previously published in studies reporting the efficacy of the gemcitabine-oxaliplatin combination (10,16,17) and close to the 8.0 months reached with gemcitabine and cisplatin (9).Before immunotherapy adjunction demonstrated improvement in survival in the first-line setting in the TOPAZ- (11) and Keynote-966 (12) phase III studies, neither targeted therapy addition (10,18) nor chemotherapy intensification with modified FOLFIRINOX (19) or the addition of albumin-bound paclitaxel succeeded in improving survival.In Asia, the addition of S-1 to gemcitabine and cisplatin in the firstline setting prolongs survival compared to the chemotherapy doublet (20).The IMBrave-151 (21) phase II trial assessed the combination of atezolizumab, bevacizumab, gemcitabine, and cisplatin and showed promising preliminary results; however, it lacked an appropriate control group with gemcitabine and cisplatin.
From a molecular perspective, BTC is a heterogeneous disease with distinct genomic and epigenomic landscapes (22,23).Based on this molecular dismemberment, targeted therapies have been used to improve outcomes beyond first-line therapy.In the present study, more than half of the patients underwent molecular testing.Two of these patients were diagnosed with FGFR pathway alterations.As expected in patients with such features, the type of BTC was ICC (24).One patient was observed to have a FGFR1 missense mutation (c.2223C>A; p.Phe741Leu) along with a synonymous FGFR3 mutation (c.933G>A; p.Thr311Thr), while the second patient was diagnosed with a FGFR2 fusion (FGFR2-C5orf15) that would have rendered him a candidate for targeted therapies since pemigatinib (25), infigratinib (26), or futibatinib (27, 28) are validated options for patients with FGFR2 fusions (13).One patient harbored a IDH2 mutation; however, ivosidenib (29,30) has only been proposed for patients with IDH1 mutations.Patients harboring BRAF mutations are candidates for dabrafenib with trametinib (31).The amplification of HER2/neu is targeted by trastuzumab, which is either associated with pertuzumab (32) or FOLFOX (33).Pembrolizumab is the preferred option for patients with mismatch repair deficiency (dMMR) or microsatellite instability (MSI-H) (34).Recently, adagrasib showed a promising efficacy in advanced BTC harboring a KRAS G12C mutation, with an ORR of 41.7% (35).Globally, molecular screening techniques enable treatment with molecular targeted agents, which prolong survival in patients with advanced BTC (36).
The choice of second-line chemotherapy for patients without targetable genomic alterations was based on retrospective and nonrandomized studies (37)(38)(39) until the ABC-06 trial established FOLFOX as the standard of care (13).After progression to firstline gemcitabine-based chemotherapy, nearly half of the patients are offered second-line chemotherapy.In a retrospective German study, nearly one-third of patients received FOLFOX/CAPOX (capecitabine-oxaliplatin) and less than a tenth was offered FOLFIRI or FOLFIRINOX (40).Studies that assessed the FOLFIRI regimen in this setting are summarized in Table 4. FOLFIRI-bevacizumab in this study allows reaching a median PFS and OS of 5.2 and 9.0 months, respectively, with a promising ORR of 21.4% and a DCR of 64.3%.Our study seems to be numerically comparable favorably with previous reports on   therapy consisting of FOLFIRI alone.In the second-line setting, the ABC-06 (14) study was the only randomized phase III trial that demonstrated the survival benefit of FOLFOX over supportive care.Despite its modest efficacy, with a median PFS of 4.0 months, median OS of 6.2 months, and poor ORR of 5%, this regimen is the standard of care after gemcitabine-based chemotherapy for patients without actionable mutations (13).Irinotecan-based therapies using nanoliposomal irinotecan (Nal-iri) were assessed.NIFTY (50), a Korean phase IIb study, and NALIRICC (51), a German phase II study, are two clinical trials that compared Nal-iri with 5-FU to 5-FU alone after gemcitabine-based therapies.While the first met its primary endpoint with an improvement of the median PFS with the Nal-iri -5-FU combination over 5-FU alone (7.1 months vs. 1.4 months; hazard ratio 0.56, 95% CI 0.39-0.81;p=0.0019), the second did not since the two regimens reached a median PFS of 2.76 and 2.3 months, respectively.These contradictory results highlight that biliary tract cancer presents with different biological features in Western and Asian countries, which may affect the response to therapy (52,53).However, the ORR were similar for NIFTY and NALIRICC (14.8% and 14.3%, respectively).Table 5 summarizes prospective randomized studies on second-line therapies for advanced BTC.
In conclusion, our study on the FOLFIRI-bevacizumab regimen after progression to first-line gemcitabine-based therapy showed promising activity with a safety profile.The survival outcomes with this combination were similar to those achieved with FOLFOX, FOLFIRI, and Nal-IRI + 5FU.However, the adjunction of an antiangiogenic agent with bevacizumab may provide a higher response rate.Hence, this regimen could benefit symptomatic patients with a massive tumor burden for whom obtaining a rapid response is crucial.

2
FIGURE 2 Kaplan-Meier survival curves with FOLFIRI-bevacizumab as the 2nd line treatment for metastatic disease.(A) overall survival; (B) progression-free survival.

3
FIGURE 3 Kaplan-Meier survival curves with FOLFIRI-bevacizumab as the 2 nd line treatment for metastatic disease within distinct tumor sites.(A) overall survival; (B) progression-free survival.

4
FIGURE 4 Kaplan-Meier survival curves with FOLFIRI-bevacizumab as the 2 nd line treatment for metastatic disease within local treatment subgroups/.(A) overall survival; (B) progression-free survival.

TABLE 1 Continued
*5 patients received surgery for resectable BTC.One patient underwent gallbladder removal for cholecystitis suspicion, which turned out to be an adenocarcinoma with peritoneal carcinomatosis.#1 patient was treated with FOLFIRINOX in the clinical trial PRODIGE 38 AMEBICA which randomized modified FOLFIRINOX versus gemcitabine-cisplatin.

TABLE 2
Overall response rate with FOLFIRI-bevacizumab as the 2 nd line treatment for metastatic disease.3%)grade≥ 3 hypertension occurred with FOLFIRI-bevacizumab but no grade ≥ 3 proteinuria.No grade 5 adverse events were reported.Table3summarizes the frequencies of AEs.

TABLE 3
Safety with FOLFIRI-bevacizumab. TABLE 4 non randomized studies that have assessed FOLFIRI in the second-line setting of advanced BTC.

TABLE 4 Continued
NA, Not applicable.

TABLE 5
Prospective randomized studies for second-line treatment of advanced BTC.