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Alqahtani et al. Hepatoma Res 2020;6:70 I http://dx.doi.org/10.20517/2394-5079.2020.65 Page 11 of 15

A third immune checkpoint inhibitor under evaluation in CCA is the PD-L1 inhibitor durvalumab. In
a phase I trial, durvalumab was evaluated as monotherapy (n = 42) or in combination with the CTLA-
[88]
4 inhibitor tremelimumab (n = 65) to treat patients with previously advanced biliary tract cancer . At
12 weeks, durvalumab monotherapy was associated with a disease control rate of 16.7%; with the
durvalumab-tremelimumab combination, this metric increased to 32.2%. The median duration of response
with durvalumab alone was 9.7 months; with the combination, it was 8.5 months. The median OS of
patients in the monotherapy cohort was 8.1 months; with durvalumab plus tremelimumab, it was 10.1 months.
The treatments were generally well-tolerated, with Grade ≥ 3 treatment-related AEs in 19% and 23% of
[88]
patients treated with monotherapy and combination, respectively . Thus, these findings reveal promising
clinical activity of durvalumab, both as monotherapy and in combination with tremelimumab in patients
with advanced biliary tract cancer. Durvalumab is also being studied in combination with chemotherapy: in
the randomized phase III TOPAZ trial, the combination of durvalumab with Gem-Cis is under evaluation
as a first-line treatment for patients with advanced biliary cancer (NCT03875235).

CONCLUSION
Patients with advanced CCA face a poor prognosis. The standard of care for these patients is gemcitabine-
based doublet chemotherapy (Gen-Cis or GemS), which has a median OS of about one year. For patients
with disease progression after first-line therapy, there is no universal standard of care. Small steps have
been made towards a personalized treatment approach for patients with CCA. The most promising
approach is the recently FDA-approved FGFR inhibitor pemigatinib in the second-line treatment of
patients with previously treated advanced CCA harboring an FGFR2 fusion or rearrangement. For patients
with an IDH1 mutation, ivosidenib treatment has been found to show progression-free efficacy. Several
other targeted therapies are being explored in molecularly oriented clinical trials of CCA: promising data
have been generated with the immune checkpoint inhibitors pembrolizumab, nivolumab, and durvalumab
in patients with advanced CCA, and it appears that immunotherapy will become an important strategy in
the treatment of these patients. The response of mismatch repair-deficient CCA patients to pembrolizumab
treatment is especially promising.

DECLARATIONS
Authors’ contributions
Made equal and substantial contribution to the conception of idea, literature review, and drafting and
finalization of manuscript: Alqahtani SA, Colombo M

Availability of data and materials
Not applicable.

Financial support and sponsorship
None.

Conflicts of interest
Both authors declared that there are no conflicts of interest.

Ethical approval and consent to participate
Not applicable.

Consent for publication
Not applicable.