High somatostatin receptor expression and efficacy of somatostatin analogues in patients with metastatic Merkel cell carcinoma.

Abstract

BACKGROUND:

Merkel cell carcinoma (MCC) is an aggressive, high-grade, cutaneous neuroendocrine tumour (NET). Agents blocking programmed death 1/programmed death ligand 1 have efficacy in metastatic MCC (mMCC), but half of patients do not derive durable benefit. Somatostatin analogues (SSAs) are commonly used to treat low- and moderate-grade NETs that express somatostatin receptors (SSTRs).

OBJECTIVES:

To assess SSTR expression and the efficacy of SSAs in mMCC, a high-grade NET. Methods In this retrospective study of 40 patients with mMCC, SSTR expression was assessed radiologically by somatostatin receptor scintigraphy (SRS; n = 39) and/or immunohistochemically when feasible (n = 9). Nineteen patients (18 had SRS uptake in MCC tumours) were treated with SSA. Disease control was defined as progression-free survival (PFS) of ≥ 120 days after initiation of SSA.

RESULTS:

Thirty-three of 39 patients (85%) had some degree (low 52%, moderate 23%, high 10%) of SRS uptake. Of 19 patients treated with SSA, seven had a response-evaluable target lesion; three of these seven patients (43%) experienced disease control, with a median PFS of 237 days (range 152-358). Twelve of 19 patients did not have a response-evaluable lesion due to antecedent radiation; five of these 12 (42%) experienced disease control (median PFS of 429 days, range 143-1757). The degree of SSTR expression (determined by SRS and/or immunohistochemistry) did not correlate significantly with the efficacy endpoints.

CONCLUSIONS:

In contrast to other high-grade NETs, mMCC tumours appear frequently to express SSTRs. SSAs can lead to clinically meaningful disease control with minimal side-effects. Targeting of SSTRs using SSA or other novel approaches should be explored further for mMCC.

• Authors: T Akaike, J Qazi, A Anderson, F S Behnia, M M Shinohara, G Akaike, D S Hippe, H Thomas, S R Takagishi, K Lachance, S Y Park, E S Tarabadkar, J G Iyer, A Blom, U Parvathaneni, H Vesselle, P Nghiem, S Bhatia
• Journal: The British journal of dermatology (Br J Dermatol) Vol. 184 Issue 2 Pg. 319-327 (02 2021) ISSN: 1365-2133 [Electronic] England
• PMID: 32320473 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2020 British Association of Dermatologists.

Chemical References

• Receptors, Somatostatin
• Somatostatin

Topics

• Carcinoma, Merkel Cell (drug therapy)
• Humans
• Receptors, Somatostatin
• Retrospective Studies
• Skin Neoplasms (drug therapy)
• Somatostatin (therapeutic use)