PD-L1 expression and clinical outcome after nivolumab monotherapy in various subtypes of melanoma: a single-institutional retrospective study

Date 25 November 2018
Event ESMO Asia 2018 Congress
Session Mini Oral - Melanoma and Sarcoma
Topics Melanoma
Personalised/Precision Medicine
Immunotherapy
Presenter Kenjiro Namikawa
Citation Annals of Oncology (2018) 29 (suppl_9): ix105-ix108. 10.1093/annonc/mdy439
Authors K. Namikawa1, T. Mori2, Y. Muto1, S. jinnai1, Y. Kage1, E. Nakano1, A. Takahashi1, N. Yamazaki1
  • 1Dermatologic Oncology, National Cancer Center Hospital, 104-0045 - Tokyo/JP
  • 2Pathology And Clinical Laboratories, National Cancer Center Hospital, 104-0045 - Tokyo/JP

Abstract

Background

Although PD-L1 expression is considered to be imperfect, it remains one of the logical biomarkers for predicting the treatment response to anti-PD-1 antibodies. However, the correlation between PD-L1 expression and clinical outcome in addition to the PD-L1 positivity rate in rare subtypes of melanoma is unclear.

Methods

To evaluate the PD-L1 positivity rate and the correlation between PD-L1 expression and clinical outcomes after nivolumab monotherapy in patients with metastatic melanoma including rare subtypes, we carried out a retrospective study using a database of National Cancer Center Hospital, Tokyo, Japan. PD-L1 status was evaluated as the percentage of tumor cells exhibiting positive membrane staining as detected using the PD-L1 IHC 28-8 pharmDx kit (Dako).

Results

We identified 147 patients with metastatic melanoma who received nivolumab monotherapy from September 2014 to February 2017. Median age was 65 (range, 17 - 92), and 74 patients (50%) were male. Non-acral cutaneous, acral cutaneous, mucosal, uveal, and unknown primary melanomas were seen in 43 (29%), 28 (19%), 54 (37%), 14 (10%), and 8 (5%) patients, respectively. Positive PD-L1 expression determined by 5% cutoff was seen in 38 (57%) out of 67 patients who had adequate tumor specimens for PD-L1 testing obtained before starting nivolumab. PD-L1 positivity rate in each subtypes were 60% (12 of 20) in non-acral cutaneous, 33% (6 of 18) in acral cutaneous, 75% (15 of 20) in mucosal, 0% (0 of 4) in uveal, and 100% (5 of 5) in unknown primary melanoma. The median progression-free survival (95%CI) in melanoma patients with negative, positive, and unknown PD-L1 status was 8.0 (3.0 – 13.0), 9.0 (6.4 – 11.6), and 3.0 (2.4 – 3.6) months, respectively (p = 0.013). The median overall survival (95%CI) in melanoma patients with negative, positive, and unknown PD-L1 status was 24.0 (20.8 – 27.2), 21.0 (15.6 – 26.4), and 10.0 (4.5 – 15.5) months, respectively (p = 0.219).

Conclusions

PD-L1 positivity rate varies among different subtypes of melanoma. PD-L1 expression seems not to be a definitive biomarker to predict clinical outcome after nivolumab monotherapy in various subtypes of melanoma.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

National Cancer Center Hospital, Tokyo, Japan.

Funding

This work was supported in part by the National Cancer Center Research and Development Fund (29-A-3) and the Practical Research for Innovative Cancer Control from the Japan Agency for Medical Research and Development (AMED) (JP18ck0106352).

Disclosure

K. Namikawa: Honoraria: Ono Pharmaceutical, Bristol-Myers Squibb, MSD, Novartis Pharmaceutical, Toray industries, Takara bio, Eisai, outside the submitted work. N. Yamazaki: Research grant: Ono Pharmaceutical, Bristol-Myers Squibb, Novartis Pharma, MSD, Merck, Takara Bio, Amgen, Sysmex; Honoraria: Ono Pharmaceutical, Bristol-Myers Squibb, Novartis Pharma, MSD, Takara Bio. All other authors have declared no conflicts of interest.