Temporary hypocalcemia induced by cetuximab sarotalocan without hypomagnesemia in a patient with hypoparathyroidism: a novel case report

Abstract Background Cetuximab sarotalocan, which utilizes the light-activatable dye IRDye700Dx conjugated with cetuximab, is a first-in-class drug based on photoimmunotherapy for treating recurrent head and neck squamous cell carcinoma. Cetuximab frequently induces hypomagnesemia and secondary hypoc...

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Main Authors: Moeko Kado, Yoshitaka Saito, Tatsuhiko Sakamoto, Takayoshi Suzuki, Yoh Takekuma, Mitsuru Sugawara
Format: Article
Language:English
Published: BMC 2025-07-01
Series:Journal of Pharmaceutical Health Care and Sciences
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Online Access:https://doi.org/10.1186/s40780-025-00465-y
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author Moeko Kado
Yoshitaka Saito
Tatsuhiko Sakamoto
Takayoshi Suzuki
Yoh Takekuma
Mitsuru Sugawara
author_facet Moeko Kado
Yoshitaka Saito
Tatsuhiko Sakamoto
Takayoshi Suzuki
Yoh Takekuma
Mitsuru Sugawara
author_sort Moeko Kado
collection DOAJ
description Abstract Background Cetuximab sarotalocan, which utilizes the light-activatable dye IRDye700Dx conjugated with cetuximab, is a first-in-class drug based on photoimmunotherapy for treating recurrent head and neck squamous cell carcinoma. Cetuximab frequently induces hypomagnesemia and secondary hypocalcemia. Herein, we report a case of independent hypocalcemia without hypomagnesemia during treatment and discuss symptom progression. Case Presentation A female patient with left epipharyngeal cancer, hypothyroidism, and hypoparathyroidism was treated with cetuximab and sarotalocan. On day 3, serum-adjusted calcium levels decreased from 9.6 to 7.4 mg/dL, increased to 8.2 mg/dL on day 9, and further increased to 8.8 mg/dL on day 27; serum magnesium levels were not evaluated. After the second administration, serum-adjusted calcium levels decreased two days later, fluctuating between 7.6 and 8.1 mg/dL for three weeks. Serum magnesium levels were within the normal range, with no significant variation detected during the second cycle. A similar symptom course was observed during the third cycle. The patient received enteral nutrition daily with 424.8–1,038.4 mg of calcium, with daily adjustment during the administration, except on day 2. She received peripheral intravenous nutrition for several days after tumor illumination. Concomitant medications did not appear to affect serum calcium levels. Considering the case process and previous reports, we hypothesized that concomitant hypoparathyroidism, in addition to reduced calcium intake due to the treatment, may have contributed to the observed reduction. Conclusions Hypocalcemia without hypomagnesemia can occur in patients with hypoparathyroidism receiving near-infrared photoimmunotherapy with cetuximab sarotalocan. The precise mechanisms and epidemiological features warrant further investigations.
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spelling doaj-art-c6f586cb7ad34617b7344975781a5d002025-08-20T03:37:38ZengBMCJournal of Pharmaceutical Health Care and Sciences2055-02942025-07-011111810.1186/s40780-025-00465-yTemporary hypocalcemia induced by cetuximab sarotalocan without hypomagnesemia in a patient with hypoparathyroidism: a novel case reportMoeko Kado0Yoshitaka Saito1Tatsuhiko Sakamoto2Takayoshi Suzuki3Yoh Takekuma4Mitsuru Sugawara5Department of Pharmacy, Hokkaido University HospitalDepartment of Clinical Pharmaceutics & Therapeutics, Faculty of Pharmaceutical Sciences, Hokkaido University of ScienceDepartment of Pharmacy, Hokkaido University HospitalDepartment of Otolaryngology-Head and Neck Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido UniversityDepartment of Pharmacy, Hokkaido University HospitalDepartment of Pharmacy, Hokkaido University HospitalAbstract Background Cetuximab sarotalocan, which utilizes the light-activatable dye IRDye700Dx conjugated with cetuximab, is a first-in-class drug based on photoimmunotherapy for treating recurrent head and neck squamous cell carcinoma. Cetuximab frequently induces hypomagnesemia and secondary hypocalcemia. Herein, we report a case of independent hypocalcemia without hypomagnesemia during treatment and discuss symptom progression. Case Presentation A female patient with left epipharyngeal cancer, hypothyroidism, and hypoparathyroidism was treated with cetuximab and sarotalocan. On day 3, serum-adjusted calcium levels decreased from 9.6 to 7.4 mg/dL, increased to 8.2 mg/dL on day 9, and further increased to 8.8 mg/dL on day 27; serum magnesium levels were not evaluated. After the second administration, serum-adjusted calcium levels decreased two days later, fluctuating between 7.6 and 8.1 mg/dL for three weeks. Serum magnesium levels were within the normal range, with no significant variation detected during the second cycle. A similar symptom course was observed during the third cycle. The patient received enteral nutrition daily with 424.8–1,038.4 mg of calcium, with daily adjustment during the administration, except on day 2. She received peripheral intravenous nutrition for several days after tumor illumination. Concomitant medications did not appear to affect serum calcium levels. Considering the case process and previous reports, we hypothesized that concomitant hypoparathyroidism, in addition to reduced calcium intake due to the treatment, may have contributed to the observed reduction. Conclusions Hypocalcemia without hypomagnesemia can occur in patients with hypoparathyroidism receiving near-infrared photoimmunotherapy with cetuximab sarotalocan. The precise mechanisms and epidemiological features warrant further investigations.https://doi.org/10.1186/s40780-025-00465-yHypocalcemiaCetuximab sarotalocanHypomagnesemiaHypoparathyroidismHypokalemiaEpidermal growth factor receptor
spellingShingle Moeko Kado
Yoshitaka Saito
Tatsuhiko Sakamoto
Takayoshi Suzuki
Yoh Takekuma
Mitsuru Sugawara
Temporary hypocalcemia induced by cetuximab sarotalocan without hypomagnesemia in a patient with hypoparathyroidism: a novel case report
Journal of Pharmaceutical Health Care and Sciences
Hypocalcemia
Cetuximab sarotalocan
Hypomagnesemia
Hypoparathyroidism
Hypokalemia
Epidermal growth factor receptor
title Temporary hypocalcemia induced by cetuximab sarotalocan without hypomagnesemia in a patient with hypoparathyroidism: a novel case report
title_full Temporary hypocalcemia induced by cetuximab sarotalocan without hypomagnesemia in a patient with hypoparathyroidism: a novel case report
title_fullStr Temporary hypocalcemia induced by cetuximab sarotalocan without hypomagnesemia in a patient with hypoparathyroidism: a novel case report
title_full_unstemmed Temporary hypocalcemia induced by cetuximab sarotalocan without hypomagnesemia in a patient with hypoparathyroidism: a novel case report
title_short Temporary hypocalcemia induced by cetuximab sarotalocan without hypomagnesemia in a patient with hypoparathyroidism: a novel case report
title_sort temporary hypocalcemia induced by cetuximab sarotalocan without hypomagnesemia in a patient with hypoparathyroidism a novel case report
topic Hypocalcemia
Cetuximab sarotalocan
Hypomagnesemia
Hypoparathyroidism
Hypokalemia
Epidermal growth factor receptor
url https://doi.org/10.1186/s40780-025-00465-y
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