Ocular Toxicity in Metastatic Melanoma Patients Treated With Mitogen-Activated Protein Kinase Kinase Inhibitors: A Case Series

Spontaneous Hyphema during Ibrutinib Treatment in a CLL Patient

Ibrutinib is an oral, first-line, targeted therapy for chronic lymphocytic leukemia (CLL). Commonly reported adverse events are diarrhea, fatigue, and musculoskeletal pain, but rarely it has been associated with visual disturbances. Here, we present a rare case of spontaneous hyphema in a 60-year-old patient with a known diagnosis of CLL on ibrutinib treatment.

MAPK Pathways in Ocular Pathophysiology: Potential Therapeutic Drugs and Challenges

Mitogen-activated protein kinase (MAPK) pathways represent ubiquitous cellular signal transduction pathways that regulate all aspects of life and are frequently altered in disease. Once activated through phosphorylation, these MAPKs in turn phosphorylate and activate transcription factors present either in the cytoplasm or in the nucleus, leading to the expression of target genes and, as a consequence, they elicit various biological responses. The aim of this work is to provide a comprehensive review focusing on the roles of MAPK signaling pathways in ocular pathophysiology and the potential to influence these for the treatment of eye diseases. We summarize the current knowledge of identified MAPK-targeting compounds in the context of ocular diseases such as macular degeneration, cataract, glaucoma and keratopathy, but also in rare ocular diseases where the cell differentiation, proliferation or migration are defective. Potential therapeutic interventions are also discussed. Additionally, we discuss challenges in overcoming the reported eye toxicity of some MAPK inhibitors.

[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.

Mitogen-activated protein kinase inhibitor-associated retinopathy (MEKAR). A clinical case

Mitogen-activated protein kinase kinase (MEK) inhibitors have significantly improved the prognosis of various types of cancer such as metastatic melanoma. However, their use is usually associated with ocular side effects. A retinopathy associated with these agents (MEKAR) has been described, consisting of the development of neurosensory detachments, generally bilateral and multiple, similar to those that appear in the central serous chorioretinopathy (CSC). Generally, optical coherence tomography allows us to differentiate the two conditions. We present the case of a 55-year-old woman in treatment with a MEK inhibitor, who developed bilateral neurosensory detachments and blurred vision, which resolved with the discontinuance of the treatment due to tumour progression.

Ibrutinib-related uveitis: A case series

Purpose

Four cases of ibrutinib-related uveitis are presented, which are to the best of our knowledge the first in the literature. Possible mechanisms of ibrutinib-mediated uveitis are explored.

Observations

Case 1 is a 60-year-old female who had been stable on 1 year of ibrutinib for chronic lymphocytic leukaemia. She was diagnosed with ibrutinib-related uveitis, which responded well to topical steroids. Case 2 is a 63-year-old male diagnosed with uveitis after 2 years of ibrutinib treatment for chronic lymphocytic leukaemia. He responded well to topical and oral steroids; however, he continued to have uveitis relapses after weaning steroids. Case 3 is a 69-year-old male diagnosed with uveitis after 18 months of ibrutinib treatment. He was trialed on topical and intravenous steroids, and restarted ibrutinib without worsening of symptoms. Case 4 is a 66-year-old female who developed uveitis after being stable on ibrutinib for 3 years. She responded well to topical steroids.

Conclusions and Importance

Inflammatory complications of tyrosine kinase inhibitors are well described. While ibrutinib, and other kinase inhibitors, are generally well-tolerated, there are increasing reports of ocular toxicities, including uveitis. It is recommended to monitor patients for potential ocular adverse effects and facilitate rapid ophthalmologic assessment.

Clinical and Morphologic Characteristics of Extracellular Signal-Regulated Kinase Inhibitor-Associated Retinopathy

PURPOSE

To investigate clinical and morphologic characteristics of serous retinal disturbances in patients taking extracellular signal-regulated kinase (ERK) inhibitors.

DESIGN

Single-center retrospective study of prospectively collected data.

PARTICIPANTS

Of 61 patients receiving ERK inhibitors for treatment of metastatic cancer, this study included 40 eyes of 20 patients with evidence of retinopathy confirmed by OCT.

METHODS

Clinical examination, fundus photography, and OCT were used to evaluate ERK inhibitor retinopathy. The morphologic features, distribution, and location of fluid foci were evaluated serially. Visual acuity (VA) and choroidal thickness measurements were compared at baseline, fluid accumulation, and resolution.

MAIN OUTCOME MEASURES

Characteristics of treatment-emergent choroid and retinal OCT abnormalities as compared with baseline OCT findings and the impact of toxicity on VA.

RESULTS

Of 20 patients with retinopathy, most showed fluid foci that were bilateral (100%), multifocal in each eye (75%), and with at least 1 focus involving the fovea (95%). All subretinal fluid foci occurred between the interdigitation zone and an intact retinal pigment epithelium. No statistical difference was found in choroidal thickness at fluid accumulation and resolution compared with baseline. Forty-five percent of eyes showed evidence of concomitant intraretinal edema localized to the outer nuclear layer. At the time of fluid accumulation, 57.5% eyes showed a decline in VA (mainly by 1-2 lines from baseline). For all eyes with follow-up, the subretinal fluid and intraretinal edema were reversible and resolved without medical intervention, and best-corrected VA at fluid resolution was not statistically different from baseline. Concomitant intraretinal fluid was not associated with worsening of VA. No patient discontinued or decreased drug dose because of retinopathy.

CONCLUSIONS

This study showed that ERK inhibitors may cause subretinal fluid foci with unique clinical and morphologic characteristics. The observed foci were similar to mitogen-activated protein kinase kinase (MEK) inhibitor-associated retinopathy and distinct from central serous chorioretinopathy. However, unlike with MEK inhibitors, an increased occurrence of concomitant intraretinal fluid without significant additive visual impact seems to occur with ERK inhibitors. In this series, ERK inhibitors did not cause irreversible loss of vision or serious eye damage; retinopathy was self-limited and did not require medical intervention.

Retinal toxicities of systemic anticancer drugs

Newer anticancer drugs have revolutionized cancer treatment in the last decade, but conventional chemotherapy still occupies a central position in many cancers, with combination therapy and newer methods of delivery increasing their efficacy while minimizing toxicities. We discuss the retinal toxicities of anticancer drugs with an emphasis on the mechanism of toxicity. Uveitis is seen with the use of v-raf murine sarcoma viral oncogene homolog B editing anticancer inhibitors as well as immunotherapy. Most of the cases are mild with only anterior uveitis, but severe cases of posterior uveitis, panuveitis, and Vogt-Koyanagi-Harada-like disease may also occur. In the retina, a transient neurosensory detachment is observed in almost all patients on mitogen-activated protein kinase kinase (MEK) inhibitors. Microvasculopathy is often seen with interferon α, but vascular occlusion is a more serious toxicity caused by interferon α and MEK inhibitors. Crystalline retinopathy with or without macular edema may occur with tamoxifen; however, even asymptomatic patients may develop cavitatory spaces seen on optical coherence tomography. A unique macular edema with angiographic silence is characteristic of taxanes. Delayed dark adaptation has been observed with fenretinide. Interestingly, this drug is finding potential application in Stargardt disease and age-related macular degeneration.

Ocular Toxicity of Targeted Anticancer Agents

The proliferation of targeted anticancer agents over the last two decades has revolutionized cancer treatment and improved survival in many previously refractory malignancies. However, many agents are associated with characteristic ophthalmic adverse effects. It is important that ophthalmologists recognize and maintain a high index of suspicion for these side effects in patients on targeted therapy. Most ophthalmic adverse effects can be treated with specific ocular therapy without discontinuation of cancer treatment, although it is important to be aware of the life-threatening and vision-threatening circumstances that would require therapy cessation in conjunction with the patient's oncologist. This review aims to summarize the ophthalmic adverse effects of targeted and hormonal anticancer agents and briefly describe their management.

Choriocapillaris Assessment In Patients Under Mek-Inhibitor Therapy For Cutaneous Melanoma: An Optical Coherence Tomography Angiography Study

PURPOSE

The present study investigates by optical coherence tomography angiography (OCTA) the retinal capillary plexus and choriocapillaris flow voids and their possible correlation with MEKAR.

METHODS

34 eyes of 17 patients (61.5 years [30.4-77.4]) with stage IV cutaneous melanoma were included prospectively. All patients showed disease progression under treatment with Nivolumab/Ipilimumab and were subsequently treated with the MEK-inhibitor Trametinib 2 mg once daily. At the start and every 6 weeks during follow-up of 4 months, patients underwent a complete ophthalmologic exam, OCTA and when needed fluorescein angiography.

RESULTS

Statistical analysis was performed on 17 eyes of 9 patients. Eight patients were excluded due to missing OCTA images or due to drop-out because of decease or change of treatment. Comparing vessel area density (P = .625 and 0.681, respectively), vessel skeleton density (P = .996 and 0.766, respectively) of the superficial and deep capillary plexus, flow void number and total flow void area (mm² and %) (P = .495; 0.197 and 0.298, respectively) of choriocapillaris slab, before and after treatment, revealed no significant difference. The evolution of choriocapillaris flow void parameter did not significantly differ in patients, who developed MEKAR compared to patients who did not.

CONCLUSION

In patients receiving MEK-inhibitor with and without MEKAR, no significant different characteristics of the retinal capillary plexus and choriocapillaris were found. These data suggest that the development of MEKAR, has no correlation with vascular alteration.

OCULAR ADVERSE EVENTS ASSOCIATED WITH MEK INHIBITORS

PURPOSE

Mitogen-activates protein kinase (MAPK) inhibitors, particularly MEK inhibitors, have shifted the treatment paradigm for metastatic BRAF-mutant cutaneous melanoma; however, oncologists, ophthalmologists, and patients have noticed different toxicities of variable importance. This review aims to provide an update of the ocular adverse events (OAEs), especially retinal toxicity, associated with the use of MEK inhibitors.

METHODS

We conducted a scientific literature search using the PubMed database up to July 2018 with the terms "MEK inhibitors" with a "review" filter and "MEK inhibitors" with a "clinical trials" filter. Phase I-III experimental studies and reviews were selected. Current principles and techniques for diagnosing and managing MEK inhibitor retinopathy and other OAEs are discussed.

RESULTS

In patients treated with MEK inhibitors, including asymptomatic patients, OAEs occur with an incidence of up to 90%. Mild to severe ophthalmic toxicities are described, including visual disturbances, a 2-line decrease in Snellen visual acuity, dry eye symptoms, ocular adnexal abnormalities, visual field defects, panuveitis, and retinal toxicities, such as different degrees of MEK-associated retinopathy, vascular injury, and retinal vein occlusion.

CONCLUSION

MEK inhibitors can lead to different degrees of retinal, uveal, and adnexal OAE, causing visual disturbances or discomfort. One of the most relevant OAE of MEK therapy is MEK inhibitor-associated retinopathy (MEKAR), which is usually mild, self-limited, and may subside after continuous use of the drug for weeks or months, or discontinuation, thereby restoring the normal visual function of the retina, with some exceptions. Ocular adverse events are often associated with other systemic adverse effects that can modify the dosage of treatment, so the communication with the oncologist is fundamental.

Ocular Complications of Checkpoint Inhibitors and Immunotherapeutic Agents: A Case Series

BACKGROUND

Ophthalmologists have a role in assessing immune-related adverse events (IRAE) in oncology patients on immunotherapy. We assessed the utility of a hospital-wide toxicity team in referring patients with new ocular symptoms for examination. We also identified new immunotherapy agents causing ocular side-effects.

DESIGN

A cohort study of eight consecutive patients on immunotherapy, who developed ocular IRAE from November 1, 2017 to June 30, 2019. All were seen at the Ocular Immunology Division of the Wilmer Eye Institute and referred by the Johns Hopkins Toxicity Team.

RESULTS

All eight patients on had IRAEs; were treated with corticosteroid drops or observation with clinical resolution. Two new agents, epocadostat and daratumumab, were associated with the development of uveitis.

CONCLUSION

Ophthalmologists play an important role in a hospital-wide toxicity team and need to include IRAEs in their differential diagnosis. Given new drug development, ophthalmologists may be the first to identify IRAEs.

Safety of BRAF+MEK Inhibitor Combinations: Severe Adverse Event Evaluation

Aim: The selective BRAF and MEK inhibitors (BRAFi+MEKi) have substantially improved the survival of melanoma patients with BRAF V600 mutations. However, BRAFi+MEKi can also cause severe or fatal outcomes. We aimed to identify and compare serious adverse events (sAEs) that are significantly associated with BRAFi+MEKi. Methods: In this pharmacovigilance study, we reviewed FDA Adverse Event Reporting System (FAERS) data in order to detect sAE reporting in patients treated with the combination therapies vemurafenib+cobimetinib (V+C), dabrafenib+trametinib (D+T) and encorafenib+binimetinib (E+B). We evaluated the disproportionate reporting of BRAFi+MEKi-associated sAEs. Significant associations were further analyzed to identify combination-specific safety signals among BRAFi+MEKi. Results: From January 2018 through June 2019, we identified 11,721 sAE reports in patients receiving BRAFi+MEKi. Comparison of BRAFi+MEKi combinations demonstrates that skin toxicities, including Stevens–Johnson syndrome, were disproportionally reported using V+C, with an age-adjusted reporting odds ratio (adj. ROR) of 3.4 (95%CI, 2.9–4.0), whereas fever was most significantly associated with D+T treatment with an adj. ROR of 1.9 (95%CI, 1.5–2.4). Significant associations using E+B treatment include peripheral neuropathies (adj. ROR 2.7; 95%CI, 1.2–6.1) and renal disorders (adj. ROR 4.1; 95%CI, 1.3–12.5). Notably, we found an increase in the proportion of Guillain–Barré syndrome reports (adj. ROR 8.5; 95%CI, 2.1–35.0) in patients administered E+B. Conclusion: BRAFi+MEKi combinations share a similar safety profile attributed to class effects, yet concomitantly, these combinations display distinctive effects that can dramatically impact patients’ health. Owing to the limitations of pharmacovigilance studies, some findings warrant further validation. However, the possibility of an increased risk for these events should be considered in patient care.

Left ventricular ejection fraction decrease related to BRAF and/or MEK inhibitors in metastatic melanoma patients: A retrospective analysis

BRAF and MEKis have revolutionized the management of BRAF^V600‐mutated melanoma patients. Left ventricular ejection fraction decrease (LVEF‐D) related to these treatments has not been thoroughly evaluated to date. The main objective of this study was to describe characteristics of LVEF‐D in melanoma patients treated with BRAF and/or MEKis. Metastatic melanoma patients treated with BRAF and/or MEKis between March 1, 2012 and May 18, 2018 were included retrospectively (Lyon Sud University Hospital, Hospices Civils de Lyon). LVEF‐D was defined as a reduction in LVEF ≥10% from baseline to a value <55%; normalization was defined as a value ≥55%. Among the 88 patients included, 12 (13.6%) experienced a LVEF‐D, including 10 grade 2 and 2 grade 3. The median onset of which was 11 months (IQR [3‐21]). No patient previously treated with beta‐blockers (n = 12) experienced a LVEF‐D. Analysis of laboratory parameters, electrocardiogram, and transthoracic echocardiography during the follow‐up did not find any predictive marker of LVEF‐D. All patients who benefited from a specific treatment of LVEF‐D had a normalization of LVEF at the end of follow‐up. LVEF recovery was significantly better for patients treated with angiotensin converting enzyme inhibitors and beta‐blockers than those who did not (P = .019). Ophthalmological adverse events were significantly more frequent in patients who experienced a LVEF‐D (P = .006) and the latter did not influence overall‐survival (P = .117) or progression‐free‐survival (P = .297). LVEF‐D is a common and easily manageable adverse event due to BRAF and MEKis. Its association with ocular toxicity suggests a close ophthalmological monitoring when LVEF‐D occurs.

Known and novel ocular toxicities of biologics, targeted agents, and traditional chemotherapeutics

PURPOSE

Increases in cancer with an aging population and the rapid development of new chemotherapeutics underscore the need for ophthalmologists to identify and manage potential ocular toxicities. This retrospective case series reports the ocular side effects of traditional and novel chemotherapeutic agents from a large center.

METHODS

The medical records of 3537 adult patients 18 years and older who presented to an academic ophthalmology department on high-risk medications identified by ICD-9 search between January 2010 and February 2015 were reviewed. A cancer diagnosis, as well as a temporal association with chemotherapeutic use and ocular side effect, was deemed necessary for inclusion in the study. The main measures were ocular side effects in cancer patients taking chemotherapy, ocular imaging abnormalities, and the outcome of each side effect.

RESULTS

Of the 161 oncology patients referred to the ophthalmology clinic for chemotherapeutic screening or ocular side effect, 31 (19.3%) were identified as having an ocular adverse reaction due to a novel or traditional chemotherapeutic medication. A novel flattening of the corneal curvature with hyperopic shift and corneal microcysts was identified in a patient taking the antibody-drug conjugate mirvetuximab soravtansine and was reversible with topical steroids. A bilateral medium-vessel choroidal vasculopathy with serous retinal detachment was seen with ipilimumab. The most frequent medication with ocular toxicity was interferon-α(2b) (IFN-α(2b)) (6/31, 19.4%); headache was typical in these patients (83.3%). Ibrutinib ocular toxicity was second most common (5/31, 16.1%), usually causing red or dry eye, while one patient developed branch retinal artery occlusion. Retinal abnormalities documented on OCT imaging occurred with IFN-α(2b), ipilimumab, binimetinib, and docetaxel, while rod-cone ERG abnormality was seen with cisplatin. Inflammatory conditions included anterior scleritis with zoledronic acid, focal eyelid inflammation with veliparib, bilateral chemosis with R-CHOP, iritis, and blepharospasm with IFN-α(2b). AION occurred with pemetrexed, and transient vision loss with hyperemic disc OS was seen with FOLFOX. Two patients (2/31, 6.5%) developed permanent vision loss. Six patients were lost to follow-up, and the clinical course was unknown (6/31, 19.4%).

CONCLUSIONS AND RELEVANCE

Cases of permanent visual loss were observed; yet, in the majority of side effects, they improved with topical therapy and/or holding the medication. Further research is needed to elucidate the incidence and the pathophysiology of these side effects and maximize patient quality of life.

FREQUENT SUBCLINICAL MACULAR CHANGES IN COMBINED BRAF/MEK INHIBITION WITH HIGH-DOSE HYDROXYCHLOROQUINE AS TREATMENT FOR ADVANCED METASTATIC BRAF MUTANT MELANOMA: Preliminary Results From a Phase I/II Clinical Treatment Trial

PURPOSE

To assess the potential ocular toxicity of a combined BRAF inhibition (BRAFi) + MEK inhibition (MEKi) + hydroxychloroquine (HCQ) regime used to treat metastatic BRAF mutant melanoma.

METHODS

Patients with stage IV metastatic melanoma and BRAF V600E mutations (n = 11, 31-68 years of age) were included. Treatment was with oral dabrafenib, 150 mg bid, trametinib, 2 mg/day, and HCQ, 400 mg to 600 mg bid. An ophthalmic examination, spectral domain optical coherence tomography, near-infrared and short-wavelength fundus autofluorescence, and static perimetry were performed at baseline, 1 month, and q/6 months after treatment.

RESULTS

There were no clinically significant ocular events; there was no ocular inflammation. The only medication-related change was a separation of the photoreceptor outer segment tip from the apical retinal pigment epithelium that could be traced from the fovea to the perifoveal retina noted in 9/11 (82%) of the patients. There were no changes in retinal pigment epithelium melanization or lipofuscin content by near-infrared fundus autofluorescence and short-wavelength fundus autofluorescence, respectively. There were no inner retinal or outer nuclear layer changes. Visual acuities and sensitivities were unchanged.

CONCLUSION

BRAFi (trametinib) + MEKi (dabrafenib) + HCQ causes very frequent, subclinical separation of the photoreceptor outer segment from the apical retinal pigment epithelium without inner retinal changes or signs of inflammation. The changes suggest interference with the maintenance of the outer retinal barrier and/or phagocytic/pump functions of the retinal pigment epithelium by effective MEK inhibition.

New features in MEK retinopathy

Background

The use of molecularly targeted therapy is becoming widespread in oncology. These agents cause tumour-specific genetic alterations in signal transduction pathways, hence less generalised toxicity. Dabrafenib, a BRAF inhibitor and Trametinib, a MEK inhibitor are two molecularly targeted agents recently approved for treatment of advanced, unresectable melanomas. MEK retinopathy is a recently introduced term describing retinal toxicity secondary to MEK inhibitors.

Case presentation

A 71-year-old man presented with ‘circular, green patches’ in his central vision for 2 weeks. He had multiple relapsed stage IV BRAF gene mutant malignant melanoma. He was on treatment with Dabrafenib (Tafinlar) for 7 months and Trametinib (Mekinist) for 4 months respectively. The fundus looked normal. The OCT scan showed bilateral symmetrical cystoid macular edema, intraretinal and subretinal fluid, thickening of elliposoid zone and subretinal granular deposits. The symptoms resolved with temporary cessation of chemotherapy but OCT signs persisted.

Conclusion

This case report identifies two new remarkable features of MEK retinopathy as thickening of ellipsoid zone and ‘starry sky’ pattern of distribution of subretinal granular deposits. These changes signify photoreceptors/ RPE toxicity and dysfunction. The subretinal granular deposits showed increased autofluorescence suggested abnormal lipofuscin clearance due to RPE dysfunction. The molecularly targeted therapy has revolutionized the cancer treatment and increased the survival rate. These agents are relatively new and recently approved for clinical use and most of them are associated with ocular toxicities. Awareness of ocular symptoms, side-effect profile of drugs, monitoring regime and liaison between oncologist and eye care professional with ocular imaging is key to early diagnosis and management of ocular adverse events.

Ocular Changes in Metastatic Melanoma Patients Treated with MEK Inhibitor Cobimetinib and BRAF Inhibitor Vemurafenib

Background

Mitogen-activated protein kinase kinase (MEK) inhibitor cobimetinib and V-raf murine sarcoma viral oncogene homolog B1 (BRAF) inhibitor vemurafenib have significantly improved the prognosis of BRAF-mutated metastatic melanoma. Some ocular symptoms and signs were recently recognized to follow this treatment. The study was aimed to investigate ocular toxicity in patients with metastatic melanoma treated with cobimetinib in combination with vemurafenib.

Patients and methods

In the prospective, observational study, patients with BRAF-mutated metastatic melanoma treated with cobimetinib in combination with vemurafenib at the Institute of Oncology Ljubljana were asked to participate. Ophthalmic examination was performed including measurement of visual acuity and intraocular pressure, slit lamp examination, funduscopy (CF), infrared-reflectance (IR) imaging and optical coherence tomography (OCT).

Results

Five out of 7 patients noticed changes in vision few days after starting the therapy with cobimetinib. In all patients, small circular lesions, described as MEKAR lesions, were documented in outer retinal layers demonstrated with OCT, IR, and CF. Changes were in the center and/or scattered over the retina almost symmetrical in both eyes in 6 patients, and asymmetrical in one patient, the latter presented also with unilateral anterior uveitis and cystoid macular edema.

Conclusions

Multiple bilateral foveal and extrafoveal small retinal lesions in the outer retinal layers develop in patients treated with MEK inhibitor in combination with BRAF inhibitor. Ophthalmologists and oncologists need to be aware of this common, yet relatively benign and often transient ocular side effect to avoid needless intervention, including the discontinuance of a potentially life-prolonging therapy.

Loss of Extracellular Signal-Regulated Kinase 1/2 in the Retinal Pigment Epithelium Leads to RPE65 Decrease and Retinal Degeneration

Recent work suggested that the activity of extracellular signal-regulated kinase 1/2 (ERK1/2) is increased in the retinal pigment epithelium (RPE) of age-related macular degeneration (ARMD) patients and therefore could be an attractive therapeutic target. Notably, ERK1/2 pathway inhibitors are used in cancer therapy, with severe and noncharacterized ocular side effects. To decipher the role of ERK1/2 in RPE cells, we conditionally disrupted the Erk1 and Erk2 genes in mouse RPE. The loss of ERK1/2 activity resulted in a significant decrease in the level of RPE65 expression, a decrease in ocular retinoid levels concomitant with low visual function, and a rapid disorganization of RPE cells, ultimately leading to retinal degeneration. Our results identify the ERK1/2 pathway as a direct regulator of the visual cycle and a critical component of the viability of RPE and photoreceptor cells. Moreover, our results caution about the need for a very fine adjustment of kinase inhibition in cancer or ARMD treatment in order to avoid ocular side effects.

Mechanisms of macular edema: Beyond the surface

Macular edema consists of intra- or subretinal fluid accumulation in the macular region. It occurs during the course of numerous retinal disorders and can cause severe impairment of central vision. Major causes of macular edema include diabetes, branch and central retinal vein occlusion, choroidal neovascularization, posterior uveitis, postoperative inflammation and central serous chorioretinopathy. The healthy retina is maintained in a relatively dehydrated, transparent state compatible with optimal light transmission by multiple active and passive systems. Fluid accumulation results from an imbalance between processes governing fluid entry and exit, and is driven by Starling equation when inner or outer blood-retinal barriers are disrupted. The multiple and intricate mechanisms involved in retinal hydro-ionic homeostasis, their molecular and cellular basis, and how their deregulation lead to retinal edema, are addressed in this review. Analyzing the distribution of junction proteins and water channels in the human macula, several hypotheses are raised to explain why edema forms specifically in the macular region. "Pure" clinical phenotypes of macular edema, that result presumably from a single causative mechanism, are detailed. Finally, diabetic macular edema is investigated, as a complex multifactorial pathogenic example. This comprehensive review on the current understanding of macular edema and its mechanisms opens perspectives to identify new preventive and therapeutic strategies for this sight-threatening condition.

Ocular toxicity due to Trametinib and Dabrafenib

Background

To report a case of uveitis and neuroretinal detachment in a patient treated with Trametinib and Dabrafenib due to metastatic cutaneous melanoma stage IV.

Case presentation

We evaluated slit lamp examination, fundoscopy, optical coherence tomography, fluorescein and indocyanine green angiography in a 66 years old man suffering visual loss. Fundoscopy showed serous neuroretinal detachment of the fovea accompanied with white spots surrounding the fovea in both eyes. Although therapy with Trametinib and Dabrafenib was stopped uveitis anterior was seen 2 weeks later. After a year, the therapy was started again and the serous neuroretinal detachment appeared once more, however without inflammatory reaction of the anterior chamber.

Conclusion

Patients treated with Trametinib and Dabrafenib should undergo consecutive eye examinations from the beginning of the therapy.

Clinical and Morphologic Characteristics of MEK Inhibitor-Associated Retinopathy: Differences from Central Serous Chorioretinopathy

PURPOSE

To investigate the clinical and morphologic characteristics of serous retinal disturbances in patients taking mitogen-activated protein kinase kinase (MEK) inhibitors.

PARTICIPANTS

A total of 313 fluid foci in 50 eyes of 25 patients receiving MEK inhibitors for treatment of their metastatic cancer, who had evidence of serous retinal detachments confirmed by optical coherence tomography (OCT).

DESIGN

Single-center, retrospective cohort study.

METHODS

Clinical examination and OCT were used to evaluate MEK inhibitor-associated subretinal fluid. The morphology, distribution, and location of fluid foci were serially evaluated for each eye. Choroidal thickness was measured at each time point (baseline, fluid accumulation, and fluid resolution). Two independent observers performed all measurements. Statistical analysis was used to correlate interobserver findings and compare choroidal thickness and visual acuity at each time point.

MAIN OUTCOME MEASURES

Comparison of OCT characteristics of retinal abnormalities at baseline to fluid accumulation.

RESULTS

The majority of patients had fluid foci that were bilateral (92%) and multifocal (77%) and at least 1 focus involving the fovea (83.3%). All fluid foci occurred between the interdigitation zone and an intact retinal pigment epithelium. The 313 fluid foci were classified into 4 morphologies, as follows: 231 (73.8%) dome, 36 (11.5%) caterpillar, 31 (9.9%) wavy, and 15 (4.8%) splitting. Best-corrected visual acuity at fluid resolution was not statistically different from baseline; and no eye lost more than 2 Snellen lines from baseline at the time of fluid accumulation. There was no statistical difference in the choroidal thickness between the different time points (baseline, fluid accumulation, and fluid resolution). A strong positive interobserver correlation was obtained for choroidal thickness measurements (r = 0.97, P < 0.0001) and grading of foci morphology (r = 0.97, P < 0.0001).

CONCLUSION

The subretinal fluid foci associated with MEK inhibitors have unique clinical and morphologic characteristics, which can be distinguished from the findings of central serous chorioretinopathy. In this series, MEK inhibitors did not cause irreversible loss of vision or serious eye damage.

Digoxin Plus Trametinib Therapy Achieves Disease Control in BRAF Wild-Type Metastatic Melanoma Patients

This is the first prospective study of a combination therapy involving a cardenolide and a MEK inhibitor for metastatic melanoma. Whereas BRAF mutant melanomas can exhibit profound responses to treatment with BRAF and MEK inhibitors, there are fewer options for BRAF wild-type melanomas. In preclinical studies, we discovered that cardenolides synergize with MEK inhibitor to promote the regression of patient-derived xenografts irrespective of BRAF mutation status. We therefore conducted a phase 1B study of digoxin 0.25 mg and trametinib 2 mg given orally once daily in 20 patients with advanced, refractory, BRAF wild-type melanomas. The most common adverse events were rash, diarrhea, nausea, and fatigue. The response rate was 4/20 or 20% with response durations of 2, 4, 6, and 8 months. The disease control rate (including partial responses and stable disease) was 13/20 or 65% of patients, including 5/6 or 83% of patients with NRAS mutant melanomas and 8/14 or 57% of NRAS wild-type melanomas. Patients with stable disease had disease control for 2, 2, 2, 4, 5, 6, 7, 10, and 10 months. Xenografts from four patients recapitulated the treatment responses observed in patients. Based on these pilot results, an expansion arm of digoxin plus MEK inhibitor is warranted for NRAS mutant metastatic melanoma patients who are refractory or intolerant of immunotherapy.

KEY POINTS

Digoxin plus trametinib is well tolerated and achieves a high rate of disease control in BRAF wild-type metastatic melanoma patients.

Ocular Toxicity of Tyrosine Kinase Inhibitors

PURPOSE/OBJECTIVES

To review common tyrosine kinase inhibitors, as well as their ocular side effects and management.
.

DATA SOURCES

A comprehensive literature search was conducted using CINAHL®, PubMed, and Cochrane databases for articles published since 2004 with the following search terms.

DATA SYNTHESIS

Tyrosine kinase inhibitors can cause significant eye toxicity.
.

CONCLUSIONS

Given the prevalence of new tyrosine kinase inhibitor therapies and the complexity of possible pathogenesis of ocular pathology, oncology nurses can appreciate the occurrence of ocular toxicities and the role of nursing in the management of these problems.
.

IMPLICATIONS FOR NURSING

Knowledge of the risk factors and etiology of ocular toxicity of targeted cancer therapies can guide nursing assessment, enhance patient education, and improve care management. Including a review of eye symptoms and vision issues in nursing assessment can enhance early detection and treatment of ocular toxicity.

Cobimetinib and vemurafenib for the treatment of melanoma

INTRODUCTION

Cobimetinib combined with vemurafenib is a new approved MEK inhibitor for first line treatment of metastatic melanoma patients with BRAF V600 mutations. It improves tumor response rates and progression free survival compared to vemurafenib alone, while decreasing toxicities due to the paradoxical activation of the MAPK signaling pathway.

AREAS COVERED

This review covers the pharmacology, efficacy, and toxicity data derived from clinical and preclinical studies on cobimetinib. It also reports ongoing trials evaluating cobimetinib to better understand future developments for this drug.

EXPERT OPINION

The combination of cobimetinib and vemurafenib seems to be more toxic than the combination therapy dabrafenib and trametinib even if these four drugs have never been compared in a randomized trial. The future of this combination depends on its capacity to be combined simultaneously or sequentially with immune based therapies to improve the durability of responses.

MEK inhibitor-associated retinopathy (MEKAR) in metastatic melanoma: Long-term ophthalmic effects

BACKGROUND

Mitogen-activated protein kinase kinase (MEK) inhibitors have aroused considerable interest in oncology. Activity has been demonstrated in various types of cancer, especially melanoma. MEK inhibitors induce a transient retinopathy, considered to be a class effect. At present, only sparse data are available on retinal effects with long-term MEK inhibition.

PATIENTS AND METHODS

In this prospective, observational study, patients with advanced melanoma participating in different phase 1/2 or phase 3 clinical trials were treated with the MEK inhibitor binimetinib, with a v-Raf murine sarcoma viral oncogene homolog B (BRAF) inhibitor, or with combination therapy. They underwent regular ophthalmological examinations including determination of visual function, biomicroscopy, dilated fundoscopy and optical coherence tomography (OCT) for a period of up to 2 years. Retinopathy was diagnosed on defined OCT criteria.

RESULTS

Sixty-two patients were investigated between 1st October 2011 and 31st July 2015: 13 were treated with the MEK inhibitor binimetinib alone, 10 with a selective BRAF inhibitor, and 39 with combination therapy. In 92% of patients on monotherapy and 100% of those on combination treatment, binimetinib caused dose-related lesions with serous neuroretinal detachments and oedema, strongly dependent on the time after medication. With continued treatment, retinal volume and thickness decreased to levels below baseline, without any apparent functional deficits or changes in structural integrity.

CONCLUSIONS

Binimetinib induces a specific retinopathy with daily fluctuations depending on the time interval after medication. The retinopathy partially recovers, but can still be detected many months later. Retinal thinning, possible first signs of retinal atrophy have been observed after long-term treatment, but, so far, without functional relevance.