Attaining Diagnostic Excellence: How the Structure and Function of a Rare Disease Service Contribute to Ending the Diagnostic Odyssey

Patients with rare or otherwise undiagnosed disorders frequently find themselves on a diagnostic odyssey, the often-prolonged journey toward diagnosis that can be characterized by significant physical, emotional, and financial hardship, as well as by diagnostic errors and delays. The wider availability of clinical exome sequencing has helped end many diagnostic odysseys, though diagnostic success rates of around 35% for exome sequencing leave many patients undiagnosed. Diagnostic yields can be improved via the implementation of advanced genetic testing modalities, though both these modalities and exome sequencing perform significantly better when paired with high-quality phenotypic data. Diagnostic centers of excellence can improve outcomes for patients on a diagnostic odyssey by providing a process and environment that address shortfalls in diagnostic access while providing high-quality phenotyping. Features of successful undiagnosed and rare disease evaluation teams are discussed and an illustrative case is provided.

Neuro-Ophthalmic Complications in Patients Treated With CTLA-4 and PD-1/PD-L1 Checkpoint Blockade

BACKGROUND

In recent years, CTLA-4 and PD-1/PD-L1 checkpoint inhibitors have proven to be effective and have become increasingly popular treatment options for metastatic melanoma and other cancers. These agents work by enhancing autologous antitumor immune responses. Immune-related ophthalmologic complications have been reported in association with checkpoint inhibitor use but remain incompletely characterized. This study seeks to investigate and further characterize the neuro-ophthalmic and ocular complications of immune checkpoint blockade treatment.

METHODS

A survey was distributed through the secure electronic data collection tool REDCap to neuro-ophthalmology specialists in the North American Neuro-Ophthalmology Society listserv. The study received human subjects approval through the University of California at Los Angeles Institutional Review Board. The survey identified patients sent for neuro-ophthalmic consultation while receiving one or more of a PD-1 inhibitor (pembrolizumab, nivolumab, or cemiplimab); PD-L1 inhibitor (atezolizumab, avelumab, or durvalumab); or the CTLA-4 inhibitor ipilimumab. Thirty-one patients from 14 institutions were identified. Patient demographics, neuro-ophthalmic diagnosis, diagnostic testing, severity, treatment, clinical response, checkpoint inhibitor drug used, and cancer diagnosis was obtained.

RESULTS

The checkpoint inhibitors used in these patients included pembrolizumab (12/31), nivolumab (6/31), combined ipilimumab with nivolumab (7/31, one of whom also received pembrolizumab during their course of treatment), durvalumab (3/31), ipilimumab (2/31), and cemiplimab (1/31). Malignant melanoma (16/31) or nonsmall cell lung carcinoma (6/31) were the most common malignancies. The median time between first drug administration and the time of ophthalmological symptom onset was 14.5 weeks. Eleven patients had involvement of the optic nerve, 7 patients had inflammatory orbital or extraocular muscle involvement, 6 patients had ocular involvement from neuromuscular junction dysfunction, 4 patients had cranial nerve palsy, and 4 patients had non neuro-ophthalmic complications. Use of systemic corticosteroids with or without stopping the checkpoint inhibitor resulted in improvement of most patients with optic neuropathy, and variable improvement for the other ophthalmic conditions.

CONCLUSION

This study describes the variable neuro-ophthalmic adverse events associated with use of immune checkpoint inhibitors and contributes a more thorough understanding of their clinical presentations and treatment outcomes. We expect this will increase awareness of these drug complications and guide specialists in the care of these patients.

Retinal cotton wool spot associated with cladribine therapy for multiple sclerosis

Cladribine has been shown to lower relapse rates and decrease disease progression in patients with relapsing forms of multiple sclerosis (MS). Reported adverse effects with use of cladribine include lymphopenia, neutropenia, and infections. Ocular complications have not previously been described with cladribine. We report the case of a patient developing visual symptoms and a large retinal cotton wool spot in association with initiation of cladribine therapy.

Pilot Study of Hyperfractionated Dosing of Lutetium-177-Labeled Antiprostate-Specific Membrane Antigen Monoclonal Antibody J591 (177 Lu-J591) for Metastatic Castration-Resistant Prostate Cancer

LESSONS LEARNED

Hyperfractionation of lutetium-177 (¹⁷⁷ Lu)-J591 for patients with metastatic castration-resistant prostate cancer did not appear to have any additional advantage over the single dose ¹⁷⁷ Lu-J591 or fractionated two-dose ¹⁷⁷ Lu-J591 therapy. Definite conclusions were challenging because of the small sample size of this study, and so further studies are needed to evaluate the viability of the hypothesis. On the basis of available data, a registration study of ¹⁷⁷ Lu-J591 (also known as TLX591) is planned and will use the two-dose fractionation schedule (Telix Pharma Q3 2019 update https://telixpharma.com/news-media/).

BACKGROUND

Phase I and II single-dose studies of lutetium-177 (¹⁷⁷ Lu)-J591, a radio-labeled antibody binding prostate-specific membrane antigen (PSMA), demonstrated safety and efficacy with dose response. Modest dose fractionation of ¹⁷⁷ Lu-J591 (2 doses) has less myelosuppression per similar cumulative dose, allowing higher doses to be administered safely. We hypothesized that additional dose fractionation would allow a higher cumulative dose, potentially with less toxicity and more efficacy.

METHODS

Men with progressive metastatic castration-resistant prostate cancer and adequate organ function were enrolled. ¹⁷⁷ Lu-J591 was administered at 25 mCi/m² every 2 weeks until the emergence of related grade 2 toxicity. ¹⁷⁷ Lu-J591 imaging was performed and circulating tumor cell (CTC) counts were measured before and after treatment along with standard monitoring.

RESULTS

Six subjects in a single cohort, with a median age of 68.6 years, were enrolled. Patients received three to six doses (cumulative 75-150 mCi/m² ). Two (33%) patients had >30% prostate-specific antigen (PSA) decline and three (50%) had CTC count decline. Two (33%) experienced grade (Gr) 4 neutropenia (without fever), three (50%) had Gr 4 thrombocytopenia (without hemorrhage), and two (33%) required platelet transfusions. Following hematological improvement, two patients developed worsening cytopenia during prostate cancer progression; bone marrow biopsies revealed infiltrative tumor replacing normal marrow elements without myelodysplasia. Targeting of known disease sites was seen on planar imaging in all.

CONCLUSION

Hyperfractionation of ¹⁷⁷ Lu-J591 is feasible but does not seem to have significant advantages over the two-dose fractionation regimen.

Pharmacologic mydriasis in an infant following parental use of topical glycopyrronium tosylate

We report the case of a 2-month-old boy with unilateral pharmacologic mydriasis from inadvertent exposure to glycopyrronium after parental use of glycopyrronium wipes. Clinician familiarity with the potential effects of glycopyrronium exposure may aid in the recognition, diagnosis, and prevention of pharmacologic mydriasis as well as the reduction of costly and unnecessary evaluations.

Acute visual loss after ipilimumab treatment for metastatic melanoma

BACKGROUND

Ipilimumab, a humanized CLTA-4 antibody is a standard therapy in the treatment of advanced melanoma. While ipilimumab provides an overall survival benefit to patients, it can be associated with immune related adverse events (IrAEs).

CASE PRESENTATION

Here we describe a patient treated with ipilimumab who experienced known IrAEs, including hypophysitis, as well as a profound vision loss due to optic neuritis. There are rare reports of optic neuritis occurring as an adverse event associated with ipilimumab treatment. Furthermore, the patient experienced multiple complications from high dose steroids used to manage his IrAEs.

CONCLUSIONS

This case highlights the need for recognition of atypical immune mediated processes associated with newer checkpoint inhibitor therapies including ipilimumab.

The neuro-ophthalmology of multiple sclerosis

Multiple sclerosis (MS) is a disease marked by focal demyelinating inflammatory plaques throughout the CNS. Neuro-ophthalmologic sequelae are common in MS and may arise from the disease itself or from treatment of the disease. Both afferent and efferent functions may be affected. Despite much progress, our understanding of the pathophysiology of MS, and the efficacy of our available treatments, remain inadequate. Here, we review the chief neuro-ophthalmologic abnormalities associated with MS and discuss the emerging diagnostic and therapeutic advances that are likely to further our understanding of MS and its treatment.

Rhodococcus equi: fatal pneumonia in a patient without AIDS

Rhodococcus equi infections are being recognized with greater frequency in immunocompromised patients and the population infected with the human immunodeficiency virus (HIV). R. equi usually causes a progressive pneumonia that may or may not cavitate and is relatively refractory to antibiotic therapy. We report a case of fatal R. equi pneumonia in a normal host.

Development and validation of an alternative dermal sensitization test: the mouse ear swelling test (MEST)

Traditional predictive tests for dermal sensitization in humans use the albino guinea pig as a model. A number of factors make the prospect of an alternative attractive. Guinea pig designs are labor intensive, require significant animal, caging, and husbandry resources, and are expensive. Extensive development and validation was conducted of an alternative using swelling of mouse ears as a quantitative end point. Ten strains of mice, ten age groups, both sexes, induction forms (number, route, timing), the use of an adjuvant, different vehicles and intervals to challenge, two induction sites, and three measurement intervals were evaluated. A methodology was developed for preparing induction sites to increase test sensitivity. A small battery of standard compounds was used to evaluate these design variables and a final test design was developed. The basic process was also demonstrated to occur in rats and guinea pigs and to be dose responsive. The final mouse ear swelling test (MEST) design was used to evaluate 72 materials representing a broad spectrum of chemicals and testing problems. These included 49 known positives and 23 known negatives. Guinea pig maximization test data on 37 of these resulting by studies conducted in our laboratories, along with closed patch guinea pig and human test data on many of these compounds, are also reported here for the first time. The MEST correctly identified 71 of 72 materials as potential human sensitizers or nonsensitizers. Additionally, both the efficacy of an occluded patch induction method and the duration of responsiveness of mice were evaluated. In the studies, the MEST was found to be an accurate, sensitive, and efficient alternative test design for evaluating delayed-contact sensitization.