Successful response to first-line treatment with osimertinib for choroidal metastasis from EGFR-mutated non-small-cell lung cancer

Effects of the CYP3A inhibitors, voriconazole, itraconazole, and fluconazole on the pharmacokinetics of osimertinib in rats

Background

Osimertinib, as third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is the first-line treatment approved to treat advanced T790M mutation-positive tumors. Triazole antifungals are therapeutic drugs for cancer patients to reduce the risk of opportunistic fungal infections. Our objective was to investigate whether three triazole antifungals (voriconazole, itraconazole, and fluconazole) could change the pharmacokinetics of osimertinib in rats.

Methods

The adult male Sprague-Dawley rats were randomly divided into four groups (n = 6): control (0.3% CMC-Na), and voriconazole (20 mg/kg), itraconazole (20 mg/kg), or fluconazole (20 mg/kg) combined with osimertinib (10 mg/kg) group. Tail vein blood samples were collected into heparin tubes at various time points within 0-48 h after osimertinib administration. Osimrtinib's plasma concentration was detected using HPLC-MS/MS system equipped with a Waters XBridge C18 column, with the mobile phase consisting of acetonitrile and 0.2% formic acid water at a flow rate of 0.5 mL/min.

Results

Co-administration with voriconazole or fluconazole increased the Cmax of osimertinib by 58.04% and 53.45%, respectively; the AUC0-t increased by 62.56% and 100.98%, respectively. However, when co-administered with itraconazole, the Cmax and AUC0-t of osimertinib only increased by 13.91% and 34.80%, respectively.

Conclusions

Our results revealed that the pharmacokinetics of osimertinib were significantly changed by voriconazole and fluconazole in rats, whereas it was slightly affected by itraconazole. This work will contribute to a more comprehensive understanding of the pharmacokinetic properties of osimertinib when co-administered with triazole antifungals.

Effect of the First-Line Therapy with Osimertinib for a Metastatic Choroidal Tumor in Advanced-Stage Lung Cancer: A Case Report

Although the advent of molecular-targeted drugs has improved the prognosis of various cancers, the long-term prognosis and side effects as the first-line therapy for metastatic choroidal tumors remain unclear. We describe a case in which the first-line therapy of osimertinib has shown long-term successful and minimum side effect responses for metastatic choroidal tumors in a patient with advanced-stage lung cancer. The patient was a 62-year-old man who complained of foggy vision and visual field defects in his left eye for 1 month. When he visited his local doctor, a serous retinal detachment was noted in the left eye, and he was referred to our hospital for further examination. The patient had no history of systemic disease. A fundus examination of his left eye showed a slightly elevated choroidal lesion along with the superior retinal vascular arcade. Optical coherence tomography showed a serous retinal detachment around the lesion. Fluorescein angiography showed that the site of the lesion had spotty and mottled hyperfluorescence in the early phase and ring hypofluorescence in the late phase. We suspected a metastatic choroidal tumor and performed a whole-body computed tomography scan, which indicated lung cancer and metastasis to the left iliac bone. The patient was referred to the department of respiratory medicine of our hospital, and after a thorough examination, a diagnosis of lung adenocarcinoma (stage IV-B, epidermal growth factor receptor [EGFR] gene mutation positive) was made. Treatment with osimertinib was initiated, and shrinkage of the primary tumor was observed. The elevated choroidal lesion and serous retinal detachment resolved after 2 months of treatment, and no recurrence was observed during the 20 months of treatment. The use of osimertinib as primary treatment for EGFR mutation-positive lung cancer was found to significantly reduce the size of metastatic choroidal tumors and to have a relatively long-lasting antitumor effect without serious ocular complications.

Sudden Vision Loss Secondary to Optic Nerve Infiltration as a Presenting Symptom of Metastatic Lung Adenocarcinoma

Purpose. To report a rare case of left-sided metastatic optic nerve infiltration and right-sided choroidal mass with exudative retinal detachment caused by EGFR exon 19 deletion positive non-small-cell lung adenocarcinoma that responded to targeted therapy with osimertinib (EGFR-TKI). Our patient demonstrated an excellent response with reduced size of the metastatic choroidal mass of the right orbit and improved visual acuity, in addition to systemic disease control. Case. A 66-year-old male patient with a history of diabetes mellitus, hypertension, and tobacco use presented with sudden vision loss in the left eye secondary to optic nerve infiltration and subacute vision loss in the right eye secondary to exudative retinal detachment from a choroidal metastasis. He was found to have a right lung mass, multiple metastatic pulmonary nodules, and liver and bone metastases. Biopsy from a mediastinal lymph node confirmed the diagnosis of metastatic lung adenocarcinoma. He was found to have exon 19 deletion on next-generation sequencing. We treated him with local radiation therapy to the left eye and systemic osimertinib (EGFR-TKI). Conclusion. To our knowledge, our case is the first report of a patient who initially presented with acute vision loss and was found to have metastatic retrobulbar optic nerve infiltration in one eye and metastatic choroidal lesion with exudative retinal detachment in the fellow eye secondary to lung adenocarcinoma. Due to the rarity of this condition, literature regarding effective treatment is scarce. Our patient demonstrated significant improvement in visual acuity and resolution of exudative retinal detachment in the right eye following osimertinib treatment and radiation therapy to the left eye. Further investigation into the role of tyrosine kinase inhibitors and radiation therapy in treating intraocular metastasis involving the optic nerve is needed.