MEK Inhibitor-Associated Central Retinal Vein Occlusion Associated with Hyperhomocysteinemia and MTHFR Variants

Ocular side effects of anticancer agents used in the treatment of gynecologic cancers

The treatment landscape of gynecologic cancers has expanded in recent years to include targeted and immune-based therapies. These therapies often have ocular side effects not seen with conventional chemotherapies, some of which can cause significant visual impairment if not recognized in a timely fashion. Clinicians must know how to appropriately identify, mitigate, and treat these ocular adverse events. Management often involves working with an interdisciplinary team of eye specialists, and it is important to know when to refer patients for specialized care. Proactive identification of eye specialists, especially in rural and community settings where access to care can be limited, may be necessary. Here, we discuss the management of common ocular toxicities seen with novel anticancer agents used to treat gynecologic cancers.

Challenges in the treatment of melanoma with BRAF and MEK inhibitors in patients with sickle cell disease: case report and review of the literature

Patients with sickle cell disease (SCD) suffer from complications due to anemia, inflammation, and vaso-occlusion. Factors that trigger sickling and/or inflammation may initiate such complications, while treatment with hydroxyurea (HU) reduces their emergence and prolongs survival. On the contrary, inhibition of the BRAF-MEK-ERK pathway with BRAF and MEK inhibitors (BRAF/MEKi) has revolutionized treatment of melanoma but their use has been correlated with inflammatory adverse events. Thus, treatment of patients with SCD with BRAF/MEKi may be quite challenging and pyrexia in those patients should be managed as a medical emergency. In this article, intrigued by the case of a 36-year-old female patient with S/β-thal under HU who was treated with dabrafenib and trametinib for melanoma, we analyze the mechanisms underlying inflammation and vaso-occlusion in SCD, the mechanisms of pyrexia and inflammation induced by BRAF/MEKi, their potential interconnections, the shared role of the inflammasome in these two entities, and the protective effect of HU in SCD. Since SCD is the most common inheritable blood disorder, the administration of BRAF/MEKi for melanoma in patients with SCD may be a rather common challenge. Thus, proper treatment with HU may pave the way for an uneventful management of such patients.

Central retinal vein occlusion in the setting of fibroblast growth factor receptor inhibition

Purpose

To report a case of central retinal vein occlusion (CRVO) in a patient being treated with a fibroblast growth factor receptor (FGFR) inhibitor.

Observations

A 54-year-old female patient with endometrial cancer presented with CRVO and cystoid macular edema while receiving lenvatinib/pembrolizumab combination therapy. The patient received treatment with intravitreal bevacizumab, after which her visual acuity improved markedly, permitting the continuation of her chemotherapy regimen without recurrence of ocular adverse events.

Conclusions and Importance

Like mitogen-activated protein kinase inhibitors, FGFR inhibitors have the potential to be associated with retinal vein occlusion. In this case, visual recovery was possible with intravitreal anti-vascular endothelial growth factor therapy, and toxicity did not recur with drug reinitiation and continuation over five years of follow-up.

[Ocular toxicity of targeted therapies with MEK inhibitors and BRAF inhibitors in the treatment of metastatic cutaneous melanoma]

INTRODUCTION

Cutaneous melanoma is a malignant tumor, which develops from dermal melanocytes. Targeted therapies have changed the therapeutic management of metastatic melanoma and improved the survival rate. Among the various targeted therapies, MEK inhibitors and BRAF inhibitors have demonstrated efficacy, but they may lead to ocular toxicity. The goal of this study was to assess the incidence of ocular complications caused by the use of MEK inhibitors and BRAF inhibitors and to report their clinical features and therapeutic management.

MATERIAL AND METHODS

This retrospective, observational, descriptive, single center study was conducted between May 2015 and December 2019 and included all patients with metastatic cutaneous melanomas treated with MEK inhibitors and BRAF inhibitors in whom ophthalmic toxicity was suspected. The data collected were demographic data (age, sex), the type of MEK inhibitors and BRAF inhibitors used, the length of time from melanoma diagnosis, mean duration of ophthalmological follow-up, time differential between starting therapy and the emergence of ocular complications, initial and final logMAR visual acuity, biomicroscopic examination of the anterior segment, dilatated fundus examination, and treatment administered.

RESULTS

Fifty-four eyes of 27 patients with a mean age of 61.3±14.3 were included. The mean time delay between melanoma diagnosis and initiation of treatment was 23.2±8 months. Twenty patients (74%) were treated with a combination of MEK inhibitors and BRAF inhibitors (trametinib/dabrafenib), 5 patients (19%) were treated with MEK inhibitor monotherapy (cobimetinib), and 2 patients (7%) were treated with BRAF inhibitor monotherapy (vemurafenib). The mean duration of ophthalmological follow-up was 77.8±29 days, and the delay between the start of therapy and the emergence of symptoms was 87.2±78 days. The mean initial visual acuity was 0.075±0.13 logMAR, and the final visual acuity was 0.01±0.03 logMAR. Twelve patients (44%) developed ocular complications due to the targeted therapy. In the patients who received combination trametinib/dabrafenib, 5 patients (18.5%) developed clinical signs of uveitis, from acute anterior uveietis to panuveitis, and 2 patients (7.4%) developed bilateral central serous chorioretinopathy; in the patients who received cobimetinib, 4 patients (14.8%) developed bilateral central serous chorioretinopathy; and one patient (3.7%) who received vemurafenib developed acute anterior uveitis. For these 12 patients with ophthalmic side effects, temporary discontinuation of therapy was chosen for six patients (22.2%), three patients (11.1%) received half the initial dose, and for three patients (11.1%), normal dosing was continued.

CONCLUSION

The two main side effects of targeted therapies are uveitis for BRAF inhibitors and central serous chorioretinopathy for MEK inhibitors. A multidisciplinary approach including ophthalmologists, dermatologists and oncologists is essential in order to adapt treatment in the advent of these ocular complications.

Phase Ib Trial of the Combination of Imatinib and Binimetinib in Patients with Advanced Gastrointestinal Stromal Tumors

PURPOSE

This phase Ib trial was designed to evaluate the safety and early efficacy signal of the combination of imatinib and binimetinib in patients with imatinib-resistant advanced gastrointestinal stromal tumors (GISTs).

PATIENTS AND METHODS

This trial used a standard 3 + 3 design to determine the recommended phase II dose (RP2D). Additional patients were enrolled on an expansion cohort at the RP2D enriching for succinate dehydrogenase (SDH)-deficient GISTs to explore potential efficacy.

RESULTS

The trial enrolled nine patients in the dose-escalation cohort and 14 in the dose-expansion cohort including six with SDH-deficient GISTs. Imatinib 400 mg daily with binimetinib 45 mg twice daily was established as the RP2D. Dose-limiting toxicity (DLT) was asymptomatic grade 4 creatinine phosphokinase (CPK) elevation. The most common non-DLT grade 3/4 toxicity was asymptomatic CPK elevation (69.6%). Other common ≥grade 2 toxicities included peripheral edema (17.4%), acneiform rash (21.7%), anemia (30.4%), hypophosphatemia (39.1%), and aspartate aminotransferase (AST) increase (17.4%). Two serious adverse events occurred (grade 2 dropped head syndrome and grade 3 central retinal vein occlusion). No unexpected toxicities were observed. Limited clinical activity was observed in KIT-mutant GIST. For SDH-deficient GISTs, one of five had confirmed RECIST1.1 partial response (PR). The median progression-free survival (mPFS) in patients with SDH-deficient GIST was 45.1 months [95% confidence interval (CI), 15.8-not estimable (NE)]; the median overall survival (mOS) was not reached (95% CI, 31.6 months-NE). One patient with a refractory metastatic SDH-deficient GIST had an exceptional pathologic response and durable clinical benefit.

CONCLUSIONS

The combination of imatinib and binimetinib is safe with manageable toxicity and has encouraging activity in SDH-deficient but not imatinib-refractory KIT/PDGFRA-mutant GISTs. The observed clinical benefits provide a motivation for a larger trial of the combination strategy in SDH-deficient GISTs.