Ocular findings in patients with histiocytosis and association with clinical and molecular features

BACKGROUND/AIMS

Ocular manifestations of histiocytosis and their genetic underpinnings are poorly characterised. This study characterises ocular sites of histiocytosis, notate genetic alterations and correlates to histiocytosis clinical features including subtype and sites of disease.

METHODS

Prospective registry-based study of predominantly adult histiocytosis patients at a single-institution tertiary referral centre. 180 eyes of 90 patients (46 males, 44 females) with histiocytosis (Erdheim-Chester disease 34, Rosai-Dorfman 20, xanthogranuloma 7, mixed histiocytosis 13, Langerhans cell histiocytosis (LCH) 15, ALK-positive histiocytosis 1). Ocular findings were categorised by the structure involved. Histiocytosis subtype, sites of disease and genetic status were correlated to ocular findings.

RESULTS

Ocular disease was present in more than half the histiocytosis patient cohort and occurred with other disease sites. Ocular findings were statistically significantly different across histiocytic subtypes with LCH subtypes having the lowest proportion of ocular findings (7%) and all other subtypes having rates of ocular findings which were five times that of patients with LCH (p=0.0009). Of patients with ocular findings, 41% of patients reported ocular symptoms and were significantly more in the group with ocular disease present versus those patients without ocular involvement. The presence of ocular findings was not statistically different by BRAFV600E, MAP2K1 or RAS isoform mutational status.

CONCLUSIONS

Ocular disease is a common feature of histiocytosis with significant visual symptomatology and occurrence in tandem with multisystem sites. Ocular findings vary by histiocytic subtype. The mutational profile of the cohort reflects known mutations in this clinical population, with no specific driver mutation associated with ocular disease.

Langerhans cell histiocytosis: NACHO update on progress, chaos, and opportunity on the path to rational cures

Langerhans cell histiocytosis (LCH) is a myeloid neoplastic disorder characterized by lesions with CD1a-positive/Langerin (CD207)-positive histiocytes and inflammatory infiltrate that can cause local tissue damage and systemic inflammation. Clinical presentations range from single lesions with minimal impact to life-threatening disseminated disease. Therapy for systemic LCH has been established through serial trials empirically testing different chemotherapy agents and durations of therapy. However, fewer than 50% of patients who have disseminated disease are cured with the current standard-of-care vinblastine/prednisone/(mercaptopurine), and treatment failure is associated with long-term morbidity, including the risk of LCH-associated neurodegeneration. Historically, the nature of LCH-whether a reactive condition versus a neoplastic/malignant condition-was uncertain. Over the past 15 years, seminal discoveries have broadly defined LCH pathogenesis; specifically, activating mitogen-activated protein kinase pathway mutations (most frequently, BRAFV600E) in myeloid precursors drive lesion formation. LCH therefore is a clonal neoplastic disorder, although secondary inflammatory features contribute to the disease. These paradigm-changing insights offer a promise of rational cures for patients based on individual mutations, clonal reservoirs, and extent of disease. However, the pace of clinical trial development behind lags the kinetics of translational discovery. In this review, the authors discuss the current understanding of LCH biology, clinical characteristics, therapeutic strategies, and opportunities to improve outcomes for every patient through coordinated agent prioritization and clinical trial efforts.

A next-generation BRAF inhibitor overcomes resistance to BRAF inhibition in patients with BRAF-mutant cancers using pharmacokinetics-informed dose escalation

RAF inhibitors have transformed treatment for BRAF V600-mutant cancer patients, but clinical benefit is limited by adaptive induction of ERK signaling, genetic alterations that induce BRAF V600 dimerization, and poor brain penetration. Next-generation pan-RAF dimer inhibitors are limited by narrow therapeutic index. PF-07799933 (ARRY-440) is a brain-penetrant, selective, pan-mutant BRAF inhibitor. PF-07799933 inhibited signaling in vitro, disrupted endogenous mutant-BRAF:wild-type-CRAF dimers, and spared wild-type ERK signaling. PF-07799933 ± binimetinib inhibited growth of mouse xenograft tumors driven by mutant BRAF that functions as dimers and by BRAF V600E with acquired resistance to current RAF inhibitors. We treated patients with treatment-refractory BRAF-mutant solid tumors in a first-in-human clinical trial (NCT05355701) that utilized a novel, flexible, pharmacokinetics-informed dose escalation design that allowed rapid achievement of PF-07799933 efficacious concentrations. PF-07799933 ± binimetinib was well-tolerated and resulted in multiple confirmed responses, systemically and in the brain, in BRAF-mutant cancer patients refractory to approved RAF inhibitors.

Mixed histiocytic neoplasms: A multicentre series revealing diverse somatic mutations and responses to targeted therapy

Histiocytic neoplasms are diverse clonal haematopoietic disorders, and clinical disease is mediated by tumorous infiltration as well as uncontrolled systemic inflammation. Individual subtypes include Langerhans cell histiocytosis (LCH), Rosai-Dorfman-Destombes disease (RDD) and Erdheim-Chester disease (ECD), and these have been characterized with respect to clinical phenotypes, driver mutations and treatment paradigms. Less is known about patients with mixed histiocytic neoplasms (MXH), that is two or more coexisting disorders. This international collaboration examined patients with biopsy-proven MXH with respect to component disease subtypes, oncogenic driver mutations and responses to conventional (chemotherapeutic or immunosuppressive) versus targeted (BRAF or MEK inhibitor) therapies. Twenty-seven patients were studied with ECD/LCH (19/27), ECD/RDD (6/27), RDD/LCH (1/27) and ECD/RDD/LCH (1/27). Mutations previously undescribed in MXH were identified, including KRAS, MAP2K2, MAPK3, non-V600-BRAF, RAF1 and a BICD2-BRAF fusion. A repeated-measure generalized estimating equation demonstrated that targeted treatment was statistically significantly (1) more likely to result in a complete response (CR), partial response (PR) or stable disease (SD) (odds ratio [OR]: 17.34, 95% CI: 2.19-137.00, p = 0.007), and (2) less likely to result in progression (OR: 0.08, 95% CI: 0.03-0.23, p < 0.0001). Histiocytic neoplasms represent an entity with underappreciated clinical and molecular diversity, poor responsiveness to conventional therapy and exquisite sensitivity to targeted therapy.

Genome-Wide Association Study Identifies the First Germline Genetic Variant Associated With Erdheim-Chester Disease

OBJECTIVE

Erdheim-Chester disease (ECD) is rare histiocytosis with a wide range of clinical manifestations. Somatic mutations are key to the pathogenesis of the disease; however, the relationship between germline genetic variants and ECD has not been examined so far. The present study aims to explore the inherited genetic component of ECD by performing the first genome-wide association study.

METHODS

After quality controls, a cohort of 255 patients with ECD and 7,471 healthy donors was included in this study. Afterward, a logistic regression followed by in silico functional annotation was performed.

RESULTS

A signal at the 18q12.3 genomic region was identified as a new susceptibility locus for ECD (P = 2.75 × 10-11 ; Odds Ratio = 2.09). This association was annotated to the SETBP1 gene, which is involved in clonal haematopoiesis. Functional annotation of this region and of the identified suggestive signals revealed additional genes that could be potentially involved in the pathogenesis of the disease.

CONCLUSION

Overall, this work demonstrates that germline genetic variants can impact on the development of ECD and suggests new pathways with a potential pathogenic role.

Mutant PIK3CA is a targetable driver alteration in histiocytic neoplasms

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasm characterized by the accumulation of clonal mononuclear phagocyte system cells expressing CD1a and CD207. In the past decade, molecular profiling of LCH as well as other histiocytic neoplasms demonstrated that these diseases are driven by MAPK activating alterations, with somatic BRAFV600E mutations in >50% of patients with LCH, and clinical inhibition of MAPK signaling has demonstrated remarkable clinical efficacy. At the same time, activating alterations in kinase-encoding genes, such as PIK3CA, ALK, RET, and CSF1R, which can activate mitogenic pathways independent from the MAPK pathway, have been reported in a subset of histiocytic neoplasms with anecdotal evidence of successful targeted treatment of histiocytoses harboring driver alterations in RET, ALK, and CSF1R. However, evidence supporting the biological consequences of expression of PIK3CA mutations in hematopoietic cells has been lacking, and whether targeted inhibition of PI3K is clinically efficacious in histiocytic neoplasms is unknown. Here, we provide evidence that activating mutations in PIK3CA can drive histiocytic neoplasms in vivo using a conditional knockin mouse expressing mutant PIK3CAH1047R in monocyte/dendritic cell progenitors. In parallel, we demonstrate successful treatment of PIK3CA-mutated, multisystemic LCH using alpelisib, an inhibitor of the alpha catalytic subunit of PI3K. Alpelisib demonstrated a tolerable safety profile at a dose of 750 mg per week and clinical and metabolic complete remission in a patient with PIK3CA-mutated LCH. These data demonstrate PIK3CA as a targetable noncanonical driver of LCH and underscore the importance of mutational analysis-based personalized treatment in histiocytic neoplasms.

Outcomes after interruption of targeted therapy in patients with histiocytic neoplasms

Little is known about outcomes following interruption of targeted therapy in adult patients with histiocytic neoplasms. This is an IRB-approved study of patients with histiocytic neoplasms whose BRAF and MEK inhibitors were interrupted after achieving complete or partial response by 18-fluorodeoxyglucose positron emission tomography (FDG-PET). 17/22 (77%) of patients experienced disease relapse following treatment interruption. Achieving a complete response prior to interruption, having a mutation other than BRAFV600E, and receiving MEK inhibition only were each associated with a statistically significant improvement in relapse-free survival. Relapse is common following treatment interruption however some patients may be suitable for limited-duration treatment.

Erdheim-Chester Disease Due to a Novel Internal Duplication of NRAS: Response to Targeted Therapy with Cobimetinib

Histiocytoses encompass a group of exceptionally rare disorders characterized by the abnormal infiltration of tissues by histocytes. Among these, Erdheim-Chester disease (ECD) stands out as a multisystem histiocytosis that typically affects bones and various other tissues. Historically, the treatment of ECD has been challenging. However, recent breakthroughs in our understanding, particularly the discovery of somatic mutations in the RAS-MAPK pathway, have opened new opportunities for targeted therapy in a significant subset of patients with ECD and other histiocytoses. In this report, we present the case of a patient with ECD harboring a previously unidentified microduplication in the NRAS gene in a small fraction of skin cells. This discovery played a pivotal role in tailoring an effective therapeutic approach involving kinase inhibitors downstream of NRAS. This case underscores the crucial role of deep sequencing of tissue samples in ECD, enabling the delivery of personalized targeted therapy to patients.

Successful treatment of non-Langerhans cell histiocytosis with the MEK inhibitor trametinib: a multicenter analysis

Erdheim-Chester disease (ECD) and Rosai-Dorfman disease (RDD) are rare non-Langerhans cell histiocytoses (non-LCHs), for which therapeutic options are limited. MAPK pathway activation through BRAFV600E mutation or other genomic alterations is a histiocytosis hallmark and correlates with a favorable response to BRAF inhibitors and the MEK inhibitor cobimetinib. However, there has been no systematic evaluation of alternative MEK inhibitors. To assess the efficacy and safety of the MEK inhibitor trametinib, we retrospectively analyzed the outcomes of 26 adult patients (17 with ECD, 5 with ECD/RDD, 3 with RDD, and 1 with ECD/LCH) treated with orally administered trametinib at 4 major US care centers. The most common treatment-related toxicity was rash (27% of patients). In most patients, the disease was effectively managed at low doses (0.5-1.0 mg trametinib daily). The response rate of the 17 evaluable patients was 71% (73% [8/11] without a detectable BRAFV600E achieving response). At a median follow-up of 23 months, treatment effects were durable, with a median time-to-treatment failure of 37 months, whereas the median progression-free and overall survival were not reached (at 3 years, 90.1% of patients were alive). Most patients harbored mutations in BRAF (either classic BRAFV600E or other BRAF alterations) or alterations in other genes involved in the MAPK pathway, eg, MAP2K, NF1, GNAS, or RAS. Most patients required lower than standard doses of trametinib but were responsive to lower doses. Our data suggest that the MEK inhibitor trametinib is an effective treatment for ECD and RDD, including those without the BRAFV600E mutation.

Mitogen-Activated Pathway Kinase Inhibitor-Associated Retinopathy: Do Features Differ with Upstream versus Downstream Inhibition?

Introduction

Many cancers have derangement of the mitogen-activated pathway kinase (MAPK), making this pathway blockade a therapeutic target. However, inhibitors of MAPK can result in adverse effects including retinopathy. This study compares clinical and morphological characteristics of serous retinal disturbances in patients taking agents with variable inhibition of MAPK: either direct interference of mitogen-activated protein kinase kinase (MEK) or extracellular signal-regulated kinase (ERK) inhibitors or with indirect inhibition via interference with FGFR signaling.

Methods

This retrospective observational study of prospectively collected pooled data is from a single tertiary oncology referral center. Of 339 patients receiving MAPK inhibitors (171, 107, and 61 on FGFR, MEK, and ERK inhibitors, respectively) for treatment of metastatic cancer, this study included 128 eyes of 65 patients with evidence of retinopathy confirmed by optical coherence tomography (OCT). The main outcome was characteristics of treatment-emergent choroid/retinal OCT abnormalities as compared to baseline OCT.

Results

In all patients on one of three drug classes (FGFRi, MEKi, ERKi), the retinopathy manifested as subretinal fluid foci that were bilateral, fovea involving, and reversible without intervention. There were notable differences between the three classes of drugs: the proportion of patients with retinopathy, number of fluid foci per eye, proportion of eyes with intraretinal edema, and the proportion of symptomatic patients was least for the upstream target (FGFR inhibitors) and greatest for the downstream targets (MEK or ERK inhibitors).

Conclusion

This study shows MAPK pathway inhibitors may cause subretinal fluid foci with unique clinical and morphological characteristics depending on the target (FGFR, MEK, or ERK) implicated. Retinopathy is more common, more symptomatic, and more severe (more fluid foci, more expansive fluid configurations) the further downstream the MAPK pathway is inhibited.

Overcoming Barriers to Tumor Genomic Profiling through Direct-to-Patient Outreach

PURPOSE

To overcome barriers to genomic testing for patients with rare cancers, we initiated a program to offer free clinical tumor genomic testing worldwide to patients with select rare cancer subtypes.

EXPERIMENTAL DESIGN

Patients were recruited through social media outreach and engagement with disease-specific advocacy groups, with a focus on patients with histiocytosis, germ cell tumors (GCT), and pediatric cancers. Tumors were analyzed using the MSK-IMPACT next-generation sequencing assay with the return of results to patients and their local physicians. Whole-exome recapture was performed for female patients with GCTs to define the genomic landscape of this rare cancer subtype.

RESULTS

A total of 333 patients were enrolled, and tumor tissue was received for 288 (86.4%), with 250 (86.8%) having tumor DNA of sufficient quality for MSK-IMPACT testing. Eighteen patients with histiocytosis have received genomically guided therapy to date, of whom 17 (94%) have had clinical benefit with a mean treatment duration of 21.7 months (range, 6-40+). Whole-exome sequencing of ovarian GCTs identified a subset with haploid genotypes, a phenotype rarely observed in other cancer types. Actionable genomic alterations were rare in ovarian GCT (28%); however, 2 patients with ovarian GCTs with squamous transformation had high tumor mutational burden, one of whom had a complete response to pembrolizumab.

CONCLUSIONS

Direct-to-patient outreach can facilitate the assembly of cohorts of rare cancers of sufficient size to define their genomic landscape. By profiling tumors in a clinical laboratory, results could be reported to patients and their local physicians to guide treatment. See related commentary by Desai and Subbiah, p. 2339.

Challenges and positive impact of rare cancer caregiving: A mixed-methods study of caregivers of patients with Erdheim-Chester disease and other histiocytic neoplasms

BACKGROUND

The importance of deriving benefit and meaning has been identified among cancer caregivers, but this has yet to be examined in the context of rare cancers. We sought to characterize unmet needs and experiences of caregivers of patients with Erdheim-Chester disease (ECD) and other histiocytic neoplasms (HN) and to identify factors associated with finding benefit and meaning-making in providing care for patients with rare cancers.

METHODS

Caregivers of patients with ECD and other HN completed quantitative surveys. Linear univariable regression modeling examined associations between unmet needs, social and family support, and intolerance of uncertainty with benefit finding and meaning-making. A subset participated in qualitative interviews assessing experiences of rare cancer caregiving that were analyzed with applied thematic analysis (NCT039900428).

FINDINGS

Of caregivers (N = 92, M = 54 years old, 68% female) of patients with ECD (75%) and other HN (25%), 78% reported moderately or severely unmet support needs, most frequently informational (58%) and psychological/emotional (66%) needs. Caregivers with unmet informational, psychological/emotional, and social support needs, difficulty tolerating uncertainty, a longer duration of the patient's illness, lower social support, more family conflict, and higher anxiety and depression symptoms demonstrated less benefit finding and meaning-making (ps <.05). Qualitative interviews (N = 19) underscored information and support needs and the capacity to derive meaning from caregiving.

INTERPRETATION

Rare cancer caregivers report numerous unmet information and support needs, needs that arise from disease rarity itself and which are associated with diminished capacity for deriving benefit and meaning from caregiving. Findings highlight targets for interventions to improve support for caregivers with HN and other rare cancers.

FUNDING

NIH P30 CA008748 (PI: Craig Thompson, MD), NIH T32 CA009461 (H.M.; PI: Jamie Ostroff, PhD), Frame Family Fund (E.L.D.), Applebaum Foundation (E.L.D.).

Treatment-Refractory Nodular Scleritis

A 59-year-old woman with a 5-year history of intermittent bilateral uveitis and scleritis presented with painful left uveitis and an episcleral nodule shown to be a uveal-episcleral lesion on ultrasound biomicroscopy. Biopsy of a nasal sinus mass 3 years earlier showed a histiocytic infiltrate with emperipolesis, consistent with Rosai-Dorfman-Destombes disease. What would you do next?

Development and feasibility of a communication training to assist caregivers with advanced care planning

OBJECTIVE

Caregivers are critical in advanced care planning (ACP) discussions, which are difficult but necessary to carry out patients' goals of care. We developed and evaluated the feasibility and acceptability of a communication training to equip caregivers of patients with malignant brain tumors with skills to navigate ACP conversations.

METHOD

Caregivers completed a 2-h virtual training addressing ACP Discussions with Your Loved One and ACP Discussions with the Medical Team. A pre-training assessment was completed at baseline and a training evaluation was completed one day post-training. A subset of participants completed semi-structured interviews 2 months post-training.

RESULTS

Of 15 caregivers recruited, 9 attended the training and 4 completed qualitative interviews. Post-training, 40% felt confident in discussing ACP with loved ones and 67% felt confident doing so with healthcare professionals; 100% reported feeling confident in using skills learned in the training to facilitate these conversations. Data from qualitative interviews highlighted additional benefits of the training in empathic communication skills and fostering social support.

SIGNIFICANCE OF RESULTS

Our communication skills training shows promise in supporting caregivers' skills and confidence in engaging in ACP discussions with patients and healthcare providers. A future randomized controlled trial with a larger and more diverse caregiving sample is needed to determine training efficacy.

Meaning-Centered Psychotherapy for Cancer Caregivers: A pilot trial among caregivers of patients with glioblastoma multiforme

Caregivers of patients with glioblastoma multiforme (GBM) are at significant risk for existential distress. Such distress negatively impacts caregivers' quality of life and capacity to serve in their role as healthcare proxies, and ultimately, contributes to poor bereavement outcomes. Our team developed Meaning-Centered Psychotherapy for Cancer Caregivers (MCP-C), the first targeted psychosocial intervention that directly addresses existential distress in caregivers. The purpose of this study was to evaluate the feasibility, acceptability, and preliminary effects of MCP-C among caregivers of patients with GBM via a mixed-method pilot trial. Caregivers were randomized to seven sessions of MCP-C or Enhanced Usual Care (EUC), which included distress screening and the provision of targeted referrals and completed quantitative assessments at baseline (T1), after completion of MCP-C (T2), and at 2-month follow-up (T3). A subset of participants engaged in semistructured interviews at T2. Of 60 caregivers randomized, 55 were evaluable for preliminary efficacy analysis. Constrained linear mixed models indicated the MCP-C arm had statistically significant improvement relative to the EUC arm in the primary outcome of personal meaning and multiple secondary outcomes, including benefit finding, depressive symptomatology, and spiritual wellbeing. MCP-C demonstrated preliminary efficacy in facilitating caregivers' capacity to experience a sense of meaning and purpose despite the challenges and suffering associated with providing care to patients with GBM. Future studies are needed among more diverse samples of caregivers and should include the opportunity for concurrent patient enrollment to allow for a reciprocal and augmented experience of meaning among patient-caregiver dyads.

Overcoming barriers to tumor genomic profiling through direct patient social media outreach

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Background: Tumor genomic profiling is increasingly used to identify actionable genomic alterations as a guide to therapy selection. To overcome barriers to genomic testing for patients with rare cancers, we initiated a program to offer free clinical tumor genomic testing worldwide to patients with select rare cancer subtypes. Methods: Patients were recruited through social media outreach, engagement with disease advocacy groups, or via physician referral, with a focus on recruiting patients with histiocytosis, germ cell tumors and rare pediatric cancers. Tumor and patient-matched germline DNA were analyzed using the MSK-IMPACT targeted sequencing next generation sequencing panel with return of results to patients and their local physicians. Whole exome recapture of MSK-IMPACT DNA sequencing libraries was performed for patients with female germ cell tumors to define the genomic landscape of this rare cancer subtype. Results: 359 cancer patients expressed interest in the Make-an-IMPACT program, of whom 333 were enrolled. Tumor tissue was received for 288 (86.4%), with 250 (86.8%) having tumor DNA of sufficient quantity and quality for MSK-IMPACT testing. 14 histiocytosis patients have received genomically guided therapy to date, of whom 13 (93%) have had clinical benefit based on local MD response assessment with a mean treatment duration of 16.7 months (range 3-32+). Whole exome sequencing of ovarian GCTs identified a subset with fully haploid genotypes, a phenotype rarely observed in other cancer types. Actionable genomic alterations were rare in ovarian GCT (28%), however, 2 ovarian GCTs and squamous transformation had high tumor mutational burden, one of whom had a complete response to pembrolizumab. Conclusions: Social media outreach can facilitate the assembly of cohorts of rare cancers of sufficient size to define their genomic landscape. By profiling tumors in a clinical laboratory, results could be reported to patients and their local physicians where they could be used to guide treatment selection. This can also open the door to diversifying and being able to study the genomic landscape in a diverse cohort.

Clinical characteristics and treatment outcomes in patients with histiocytic neoplasms harboring class 3 MAP2K1 mutations, including treatment with the ERK inhibitor ulixertinib

e19081

Background: Histiocytic neoplasms (HN) are clonal myeloid disorders with diverse clinical phenotypes. HN nearly invariably harbor mutations of the mitogen activated protein kinase (MAPK) pathway, including the BRAFV600E mutation in HN subtypes that are responsive to BRAF inhibition. More recently characterized, the second most frequently mutated gene driving HN is MAP2K1, with broad responsiveness to MEK inhibition reported. The most common MAP2K1 variant observed in our cohort (n=300 patients) is the exon 3 p.E102_I103 in-frame deletion, among the Class 3 MAP2K1 mutants predicted to be resistant to allosteric MEK inhibition. We present clinical and treatment characteristics of HN patients with Class 3 MAP2K1 mutations. Methods: Patients with HN and exon 3 p.E102_I103del or similar mutations identified by tumor sequencing were included. Sites of disease were captured. First- and later-line treatments were categorized as observation, chemotherapy (vinblastine, cytarabine, cladribine, methotrexate), immune modulation (anakinra or interferon), MEK inhibition (trametinib or cobimetinib), or ERK inhibition (ulixertinib). Clinical and radiologic responses were captured as partial response (PR), complete response (CR), or progressive disease (PD). PD includes relapse following PR or CR. Results: 16 patients were identified. 8 (50%) were female, and median age at HN diagnosis was 31 (range 22-58). 10 patients had Langerhans cell histiocytosis (LCH), 4 had Erdheim-Chester disease (ECD), 2 had mixed histiocytosis. Sites of HN were bone (16; 100%), lymph node (8; 50%), brain (8; 50%), skin/subcutaneous (4; 25%), retroperitoneum (3; 19%), cardiovascular (3; 19%), abdomen (2; 13%), reproductive (1; 6%) and other sites (5; 31%). Mutations identified were MAP2K1 p.E102_103del (13; 81%), p.L101_103delinsF (1; 6%), p.P105_I107delinsL (1; 6%), and p.I103_A106del (1; 6%). 2 (13%) patients had spontaneous regression of disease and were observed; 3 (19%) patients had CR to first-line chemotherapy. 3 (19%) patients have had CR/PR to first-line MEK inhibition. 8 (50%) patients had PD following chemotherapy and/or immune modulation; of those, 1 was lost to follow-up, 4 had CR/PR to MEK inhibition; however, 3 had PD despite MEK inhibition. These three patients and one treatment-naïve patient were treated with an oral ERK1/2 inhibitor, ulixertinib, on prospective protocols. 3 of 4 had a clinical or radiologic PR (1) or CR (2). Conclusions: Histiocytic neoplasms with Class 3 MAP2K1 mutations represent a diverse spectrum of disease characterized by frequent bone, nodal and neurologic involvement, by frequent resistance to chemotherapy. This entity is resistant to MEK inhibition in some patients, a phenomenon previously undocumented, and responsive to ERK inhibition, which may be a promising therapeutic approach to HN.

Multi-institutional study of the frequency, genomic landscape, and outcome of IDH-mutant glioma in pediatrics

BACKGROUND

The incidence and biology of IDH1/2 mutations in pediatric gliomas are unclear. Notably, current treatment approaches by pediatric and adult providers vary significantly. We describe the frequency and clinical outcomes of IDH1/2-mutant gliomas in pediatrics.

METHODS

We performed a multi-institutional analysis of the frequency of pediatric IDH1/2-mutant gliomas, identified by next-generation sequencing (NGS). In parallel, we retrospectively reviewed pediatric IDH1/2-mutant gliomas, analyzing clinico-genomic features, treatment approaches, and outcomes.

RESULTS

Incidence: Among 851 patients with pediatric glioma who underwent NGS, we identified 78 with IDH1/2 mutations. Among patients 0-9 and 10-21 years old, 2/378 (0.5%) and 76/473 (16.1%) had IDH1/2-mutant tumors, respectively. Frequency of IDH mutations was similar between low-grade glioma (52/570, 9.1%) and high-grade glioma (25/277, 9.0%). Four tumors were graded as intermediate histologically, with one IDH1 mutation. Outcome: Seventy-six patients with IDH1/2-mutant glioma had outcome data available. Eighty-four percent of patients with low-grade glioma (LGG) were managed observantly without additional therapy. For low-grade astrocytoma, 5-year progression-free survival (PFS) was 42.9% (95%CI:20.3-63.8) and, despite excellent short-term overall survival (OS), numerous disease-related deaths after year 10 were reported. Patients with high-grade astrocytoma had a 5-year PFS/OS of 36.8% (95%CI:8.8-66.4) and 84% (95%CI:50.1-95.6), respectively. Patients with oligodendroglioma had excellent OS.

CONCLUSIONS

A subset of pediatric gliomas is driven by IDH1/2 mutations, with a higher rate among adolescents. The majority of patients underwent upfront observant management without adjuvant therapy. Findings suggest that the natural history of pediatric IDH1/2-mutant glioma may be similar to that of adults, though additional studies are needed.

Coping with glioblastoma: prognostic communication and prognostic understanding among patients with recurrent glioblastoma, caregivers, and oncologists

PURPOSE

Glioblastoma (GBM) is a devastating neuro-oncologic disease with invariably poor prognosis. Despite this, research shows patients have unrealistic perceptions of their prognosis, which may relate in part to communication patterns between patients, caregivers and oncologists. The purpose of this study was to examine communication processes and goals among patients, caregivers, and oncologists to elucidate drivers of prognostic understanding (PU) in the context of recurrent GBM.

METHODS

This was a prospective, multi-center study enrolling adult patients with GBM, caregivers, and oncologists, who independently reported the content of a specific discussion involving the disclosure of GBM recurrence. Communication processes and goals were characterized for each participant, and concordance between all dyads and patient-caregiver-oncologist triads were calculated.

RESULTS

Seventeen patient, caregiver, and oncologist triads were analyzed. At the individual level, three (17.6%) patients and 8 (47.1%) caregivers reported having discussed prognosis during the clinical encounter, as compared to ten oncologists (58.8%). Seven patients (41.2%) and 5 caregivers (29.4%), versus thirteen oncologists (76.5%) reported ever discussing prognosis or life expectancy at previous appointments. Generally, patient-caregiver concordance (i.e., both answered the same) regarding communication goals and processes was low. Triads showed limited concordant responses in discussing curability (n = 5), prognosis (n = 4), end-of-life treatment goals (n = 4), and ever discussing prognosis (n = 3).

CONCLUSION

Patients, caregivers and oncologists had discordant views regarding communication processes and prognostic goals, even when recalling a single discussion. This study highlights the importance of clear and frequent communication about prognosis, and the need for further research on communication and PU in the neuro-oncology setting.

International expert consensus recommendations for the diagnosis and treatment of Langerhans cell histiocytosis in adults

Langerhans cell histiocytosis (LCH) can affect children and adults with a wide variety of clinical manifestations, including unifocal, single-system multifocal, single-system pulmonary (smoking-associated), or multisystem disease. The existing paradigms in the management of LCH in adults are mostly derived from the pediatric literature. Over the last decade, the discovery of clonality and MAPK-ERK pathway mutations in most cases led to the recognition of LCH as a hematopoietic neoplasm, opening the doors for treatment with targeted therapies. These advances have necessitated an update of the existing recommendations for the diagnosis and treatment of LCH in adults. This document presents consensus recommendations that resulted from the discussions at the annual Histiocyte Society meeting in 2019, encompassing clinical features, classification, diagnostic criteria, treatment algorithm, and response assessment for adults with LCH. The recommendations favor the use of 18F-Fluorodeoxyglucose positron emission tomography-based imaging for staging and response assessment in the majority of cases. Most adults with unifocal disease may be cured by local therapies, while the first-line treatment for single-system pulmonary LCH remains smoking cessation. Among patients not amenable or unresponsive to these treatments and/or have multifocal and multisystem disease, systemic treatments are recommended. Preferred systemic treatments in adults with LCH include cladribine or cytarabine, with the emerging role of targeted (BRAF and MEK inhibitor) therapies. Despite documented responses to treatments, many patients struggle with a high symptom burden from pain, fatigue, and mood disorders that should be acknowledged and managed appropriately.

Rosai-Dorfman-Destombes disease of the nervous system: a systematic literature review

Background

Rosai–Dorfman–Destombes disease (RDD) is a rare histiocytic disorder with heterogeneous clinical manifestations and rare neurologic involvement. The existing clinical literature about neurologic RDD has yet to be critically examined.

Methods

We performed a four-database English-language systematic literature search for cases of RDD neurohistiocytosis, excluding secondary literature. Individual patient data for neurologic symptoms, disease sites, treatments, and responses were captured. Responses to first-line and second-line surgical interventions, post-surgical radiotherapy, and systemic therapies were analyzed.

Results

Among 4769 articles yielded by literature search, 154 articles were fully reviewed, containing data on 224 patients with neurologic RDD. 128 (83.1%) articles were single case reports. 149 (66.5%) patients were male, 74 (33.5%) female, with a median age of 37.6 years (range 2–79). Presenting neurologic symptoms included headache (45.1%), focal neurological deficits (32.6%), visual symptoms (32.1%), and seizures (24.6%). RDD involvement was multifocal in 32 (14.3%) cases. First-line treatment involved resection in 200 (89.6%) patients, with subsequent progression in 52 (26%), including 41 (78.8%) with unifocal disease. No difference was observed in progression-free survival comparing post-operative radiotherapy to no radiotherapy following partial resection. Chemotherapy given alone as first-line treatment led to complete or partial response in 3/7(43%) patients. Second-line treatments led to complete or partial response in 18/37(37.5%) patients. Mutational data were reported on 10 patients (4.46%).

Conclusions

This review highlights the limited published data about neurologic RDD, which presents with varied symptomatology and outcome. Further study is needed about its mutational landscape, and more effective therapies are needed for recurrent and refractory disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02220-0.

ALK-positive histiocytosis: a new clinicopathologic spectrum highlighting neurologic involvement and responses to ALK inhibition

ALK-positive histiocytosis is a rare subtype of histiocytic neoplasm first described in 2008 in 3 infants with multisystemic disease involving the liver and hematopoietic system. This entity has subsequently been documented in case reports and series to occupy a wider clinicopathologic spectrum with recurrent KIF5B-ALK fusions. The full clinicopathologic and molecular spectra of ALK-positive histiocytosis remain, however, poorly characterized. Here, we describe the largest study of ALK-positive histiocytosis to date, with detailed clinicopathologic data of 39 cases, including 37 cases with confirmed ALK rearrangements. The clinical spectrum comprised distinct clinical phenotypic groups: infants with multisystemic disease with liver and hematopoietic involvement, as originally described (Group 1A: 6/39), other patients with multisystemic disease (Group 1B: 10/39), and patients with single-system disease (Group 2: 23/39). Nineteen patients of the entire cohort (49%) had neurologic involvement (7 and 12 from Groups 1B and 2, respectively). Histology included classic xanthogranuloma features in almost one-third of cases, whereas the majority displayed a more densely cellular, monomorphic appearance without lipidized histiocytes but sometimes more spindled or epithelioid morphology. Neoplastic histiocytes were positive for macrophage markers and often conferred strong expression of phosphorylated extracellular signal-regulated kinase, confirming MAPK pathway activation. KIF5B-ALK fusions were detected in 27 patients, whereas CLTC-ALK, TPM3-ALK, TFG-ALK, EML4-ALK, and DCTN1-ALK fusions were identified in single cases. Robust and durable responses were observed in 11/11 patients treated with ALK inhibition, 10 with neurologic involvement. This study presents the existing clinicopathologic and molecular landscape of ALK-positive histiocytosis and provides guidance for the clinical management of this emerging histiocytic entity.

OUP accepted manuscript

Background

Population-based analyses of patterns of care and survival of older patients diagnosed with grade II-III oligodendroglioma (OLI) or astrocytoma (AST) can aid clinicians in their understanding and care of these patients.

Methods

We identified patients diagnosed between 2006 and 2015 with primary glioma diagnoses (OLI or AST) who were older than 65 years using the latest release of the Surveillance, Epidemiology, and End Results-Medicare–linked database. Medicare claims were used to identify cancer treatments (surgery, chemotherapy, and radiation therapy) from 2006 to 2016. Kaplan-Meier methodology was used to describe overall survival (OS). Cox proportional hazards regression was used to associate variables of interest, including treatments in a time-dependent manner, with OS. Hazard ratios (HRs) and 95% confidence intervals (CIs) from multivariable, cause-specific competing risk models identified associations with treatments. All statistical tests were 2-sided.

Results

We identified 1291 patients comprising 158 with OLI, 1043 with AST, and 90 with mixed histologies. Median OS was 6.5 (95% CI = 6.1 to 7.3) months for the overall cohort, 22.6 (95% CI = 13.9 to 33.1) months for OLI, and 5.8 (95% CI = 5.3 to 6.4) months for AST. Patients who received surgery and patients who received both chemotherapy and radiation therapy in combination experienced better OS (HR = 0.87, 95% CI = 0.79 to 0.96, and HR = 0.58, 95% CI = 0.35 to 0.96, respectively). Over the time frame studied, there was a 4.0% increase per year in prescription of chemotherapy (P = .03) and a 2.0% improvement in OS for each calendar year (P = .003).

Conclusions

We provide population-based evidence that patients older than 65 years with grade II-III glioma have experienced increased chemotherapy use as well as improvement in survival over time.

Progressive nodular histiocytosis in a 9-year-old boy treated with cobimetinib

Progressive nodular histiocytosis is a rare variant of non-Langerhans cell histiocytosis that affects the skin and mucous membranes and displays a progressive clinical course and poor response to treatment. We describe a case of severe progressive nodular histiocytosis harboring a KRAS p.G12S mutation in a 9-year-old boy, refractory to chemotherapy, who was successfully treated with the MEK inhibitor cobimetinib. This is the first report of the use of MEK inhibition for this histiocytosis subtype in a pediatric patient.

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.

Ethics consultations in neuro-oncology

Background

Management of patients with brain tumors can lead to ethical and decisional dilemmas. The aim of this study was to characterize ethical conflicts encountered in neuro-oncologic patients.

Methods

Retrospective review of ethics consultations performed upon patients with primary and metastatic brain tumors at a tertiary cancer center. An ethics consultation database was examined to characterize ethical conflicts, contextual factors, and interventions by the consultation team.

Results

Fifty consultations were reviewed; 28 (56%) patients were women, median age 54 (range 4-86); 27 (54%) patients had a primary central nervous system malignancy; 20 (40%) had brain metastasis. At the time of consultations, 41 (82%) patients lacked decisional capacity; 48 (96%) had a designated surrogate decision maker; 3 (6%) had an advance directive outlining wishes regarding medical treatment; 12 (24%) had a Do Not Attempt Resuscitation (DNAR) order. Ethical conflicts centered upon management of end-of-life (EOL) circumstances in 37 (72%) of cases; of these, 30 did not have decisional capacity. The most common ethical issues were DNAR status, surrogate decision making, and request for nonbeneficial treatment. Consultants resolved conflicts by facilitating decision making for incapacitated patients in 30 (60%) cases, communication between conflicting parties in 10 (20%), and re-articulation of patients' previously stated wishes in 6 (12%).

Conclusions

Decisional capacity at EOL represents the primary ethical challenge in care of neuro-oncologic patients. Incomplete awareness among surrogate decision makers of patients' prognosis and preferences contributes to communication gaps and dilemmas. Early facilitation of communication between patients, caregivers, and medical providers may prevent or mitigate conflicts and allow the enactment of patients' goals and values.

Trial in progress: Phase 1a/b study of PF-07284890 (brain-penetrant BRAF inhibitor) with/without binimetinib in patients with BRAF V600-mutant solid tumors

TPS3152

Background: BRAF inhibitors have transformed treatment (Tx) for patients (pts) with BRAF V600-mutant cancers, but long-term efficacy is limited by disease progression in the brain, due to poor brain penetration. PF-07284890 is a potent, selective, highly brain-penetrant, small-molecule inhibitor of BRAF V600 mutations. This first in human study will assess the PK, safety, and preliminary clinical activity of PF-07284890, as monotherapy and in combination with binimetinib (MEK inhibitor), in pts with BRAF V600-mutated advanced solid tumors with/without brain metastases. Methods: Phase 1a/1b open-label, multicenter, dose-finding study (NCT04543188). Pts will be ≥18 y with a histologically confirmed advanced/metastatic solid tumor including primary brain tumor (PBT), confirmed BRAF V600 mutation, and presence/absence of brain involvement. Pts will have disease progression despite prior Tx without alternative Tx options. Pts with brain metastasis/PBT > 4 cm and/or symptomatic brain disease will be excluded initially, but allowed based on emerging PK. Phase 1a is a dose escalation study of PF-07284890 (monotherapy and combination). ̃35 pts will be enrolled to determine maximum tolerated dose (MTD) and/or recommended dose for expansion (RDE) of PF-07284890 (monotherapy and combination). Cohorts of 2-4 pts will be treated at each dose level of PF-07284890 until MTD/RDE determination (PF-07284890 starting dose: 50 mg QD; binimetinib 45 mg BID). Bayesian Logistic Regression Model will be used to inform dose level decisions. At least 6 pts each for monotherapy and combination will be treated at MTD/RDE. Phase 1a primary endpoints: Cycle 1 dose-limiting toxicities; MTD/RDE; AEs; lab abnormalities; and dose interruptions, modifications and discontinuations due to AEs. Secondary endpoints include PK parameters and overall response (RECIST; overall and intracranial; RANO for PBT). Phase 1b is a dose expansion and drug-drug interaction study to further evaluate PF-07284890 + binimetinib. Cohorts 1-4 (̃40 pts each) will enroll pts based on tumor type, brain involvement (asymptomatic/symptomatic), and prior Tx. Cohort 5 (̃20 pts) will include pts with any solid tumor including leptomeningeal metastases. Cohort 6 (̃10 pts) will assess the effect of PF-07284890 + binimetinib on CYP3A activity using midazolam as a substrate. Phase 1b primary endpoint: overall response (RECIST; overall and intracranial; RANO for PBT). Secondary endpoints: duration of response; progression-free survival; disease control rate; time to response; overall survival; AEs; lab abnormalities; and dose interruptions, modifications and discontinuations due to AEs; and PK parameters. For both Phase 1a and 1b, Tx will continue until disease progression, unacceptable toxicity or patient refusal. Study began enrolling pts in January 2021 and is ongoing. Clinical trial information: NCT04543188.

Histiocytosis and the nervous system: from diagnosis to targeted therapies

Histiocytoses are heterogeneous hematopoietic diseases characterized by the accumulation of CD68(+) cells with various admixed inflammatory infiltrates. The identification of the pivotal role of the mitogen-activated protein kinase (MAPK) pathway has opened new avenues of research and therapeutic approaches. We review the neurologic manifestations of 3 histiocytic disorders with frequent involvement of the brain and spine: Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), and Rosai-Dorfman-Destombes disease (RDD). Central nervous system (CNS) manifestations occur in 10%-25% of LCH cases, with both tumorous or neurodegenerative forms. These subtypes differ by clinical and radiological presentation, pathogenesis, and prognosis. Tumorous or degenerative neurologic involvement occurs in 30%-40% of ECD patients and affects the hypothalamic-pituitary axis, meninges, and brain parenchyma. RDD lesions are typically tumorous with meningeal or parenchymal masses with strong contrast enhancement. Unlike LCH and ECD, neurodegenerative lesions or syndromes have not been described with RDD. Familiarity with principles of evaluation and treatment both shared among and distinct to each of these 3 diseases is critical for effective management. Refractory or disabling neurohistiocytic involvement should prompt the consideration for use of targeted kinase inhibitor therapies.

Neurologic and oncologic features of Erdheim-Chester disease: a 30-patient series

BACKGROUND

Erdheim-Chester disease (ECD) is a rare histiocytic neoplasm characterized by recurrent alterations in the MAPK (mitogen-activating protein kinase) pathway. The existing literature about the neuro-oncological spectrum of ECD is limited.

METHODS

We present retrospective clinical, radiographic, pathologic, molecular, and treatment data from 30 patients with ECD neurohistiocytic involvement treated at a tertiary center.

RESULTS

Median age was 52 years (range, 7-77), and 20 (67%) patients were male. Presenting symptoms included ataxia in 19 patients (63%), dysarthria in 14 (47%), diabetes insipidus in 12 (40%), cognitive impairment in 10 (33%), and bulbar affect in 9 (30%). Neurosurgical biopsy specimens in 8 patients demonstrated varied morphologic findings often uncharacteristic of typical ECD lesions. Molecular analysis revealed mutations in BRAF (18 patients), MAP2K1 (5), RAS isoforms (2), and 2 fusions involving BRAF and ALK. Conventional therapies (corticosteroids, immunosuppressants, interferon-alpha [IFN-α], cytotoxic chemotherapy) led to partial radiographic response in 8/40 patients (20%) by MRI with no complete responses, partial metabolic response in 4/16 (25%), and complete metabolic response in 1/16 (6%) by 18F-fluorodeoxyglucose (FDG)-PET scan. In comparison, targeted (kinase inhibitor) therapies yielded partial radiographic response in 10/27 (37%) and complete radiographic response in 14/27 (52%) by MRI, and partial metabolic response in 6/25 (24%) and complete metabolic response in 17/25 (68%) by FDG-PET scan.

CONCLUSIONS

These data highlight underrecognized symptomatology, heterogeneous neuropathology, and robust responses to targeted therapies across the mutational spectrum in ECD patients with neurological involvement, particularly when conventional therapies have failed.

18F-FDG PET/CT versus anatomic imaging for evaluating disease extent and clinical trial eligibility in Erdheim-Chester disease: results from 50 patients in a registry study

OBJECTIVES

The aim of this study was to [1] characterize distribution of Erdheim-Chester Disease (ECD) by 18F-FDG PET/CT and [2] determine the utility of metabolic (18F-FDG PET/CT) imaging versus anatomic imaging (CT or MRI) in evaluating ECD patients for clinical trial eligibility.

METHODS

18F-FDG PET/CT and corresponding CT or MRI studies for ECD patients enrolled in a prospective registry study were reviewed. Sites of disease were classified as [1] detectable by 18F-FDG PET only, CT/MRI only, or both and as [2] measurable by modified PERCIST (mPERCIST) only, RECIST only, or both. Descriptive analysis was performed and paired t test for between-group comparisons.

RESULTS

Fifty patients were included (mean age 51.5 years; range 18-70 years). Three hundred thirty-three disease sites were detected among all imaging modalities, 188 (56%) by both 18F-FDG PET and CT/MRI, 67 (20%) by 18F-FDG PET only, 75 (23%) by MRI brain only, and 3 (1%) by CT only. Of 178 disease sites measurable by mPERCIST or RECIST, 40 (22%) were measurable by both criteria, 136 (76%) by mPERCIST only, and 2 (1%) by RECIST only. On the patient level, 17 (34%) had mPERCIST and RECIST measurable disease, 30 (60%) had mPERCIST measurable disease only, and 0 had RECIST measurable disease only (p < 0.0001).

CONCLUSION

Compared with anatomic imaging, 18F-FDG PET/CT augments evaluation of disease extent in ECD and increases identification of disease sites measurable by formal response criteria and therefore eligibility for clinical trials. Complementary organ-specific anatomic imaging offers the capacity to characterize sites of disease in greater anatomic detail.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03329274.

Lack of survival advantage among re-resected elderly glioblastoma patients: a SEER-Medicare study

BACKGROUND

The survival benefit of re-resection for glioblastoma (GBM) remains controversial, owing to the immortal time bias inadequately considered in many studies where re-resection was treated as a fixed, rather than a time-dependent factor. Using the Surveillance, Epidemiology, and End Results-Medicare (SEER-Medicare) database, we assessed treatment patterns for older adults and evaluated the association between re-resection and overall survival (OS), accounting for the timing of re-resection.

METHODS

This retrospective cohort study included elderly patients (age ≥66) in the SEER-Medicare linked database diagnosed with GBM between 2006 and 2015 who underwent initial resection. Time-dependent Cox regression was used to assess the association between re-resection and OS, controlling for age, gender, race, poverty level, geographic region, marital status, comorbidities, receipt of radiation + temozolomide, and surgical complications.

RESULTS

Our analysis included 3604 patients with median age 74 (range: 66-96); 54% were men and 94% were white. After initial resection, 44% received radiation + temozolomide and these patients had a lower hazard of death (hazard ratio [HR]: 0.28, 95% confidence interval [CI]: 0.26-0.31, P < .001). In total, 9.5% (n = 343) underwent re-resection. In multivariable analyses, no survival benefit was seen for patients who underwent re-resection (HR: 1.12, 95% CI: 0.99-1.27, P = .07).

CONCLUSIONS

Re-resection rates were low among elderly GBM patients, and no survival advantage was observed for patients who underwent re-resection. However, patients who received standard of care at initial diagnosis had a lower risk of death. Older adults benefit from receiving radiation + temozolomide after initial resection, and future studies should assess the relationship between re-resection and OS taking the time of re-resection into account.

Necrotizing myositis in a rectus muscle arising in the setting of long-standing Langerhans cell histiocystosis and recent dabrafenib treatment

Purpose

to describe an unusual case of necrotizing myositis in a rectus muscle, possibly related to BRAF inhibitor therapy.

Observations

An 18-year old man with neurodegenerative Langerhans cell histiocytosis (LCH), recently started on the BRAF inhibitor dabrafenib, presented with right eye pain. Magnetic resonance imaging (MRI) orbits revealed a rectus muscle mass concerning for LCH recurrence or malignancy. Dabrafenib was stopped, and incisional biopsy of the mass was performed. The mass was absent on post-operative MRI, so no further treatment was pursued. Histopathologic evaluation was initially concerning for sarcoma, but on further analysis, appeared more consistent with necrotizing myositis. The mass did not recur, nor did the patient develop other signs or symptoms concerning for myositis or malignancy over a 24-month follow-up period.

Conclusions

Necrotizing myositis has not been previously described in a rectus muscle or with BRAF inhibitor use, though myalgias and malignancies are established side effects. Necrotizing myositis may masquerade as sarcoma and should be on the differential diagnosis for a new mass in the setting of dabrafenib therapy.

Pan-Cancer Efficacy of Vemurafenib in BRAF V600-Mutant Non-Melanoma Cancers

BRAF V600 mutations occur in a wide range of tumor types, and RAF inhibition has become standard in several of these cancers. Despite this progress, BRAF V600 mutations have historically been considered a clear demonstration of tumor lineage context-dependent oncogene addiction, based predominantly on the insensitivity to RAF inhibition in colorectal cancer. However, the true broader activity of RAF inhibition pan-cancer remains incompletely understood. To address this, we conducted a multicohort "basket" study of the BRAF inhibitor vemurafenib in non-melanoma BRAF V600 mutation-positive solid tumors. In total, 172 patients with 26 unique cancer types were treated, achieving an overall response rate of 33% and median duration of response of 13 months. Responses were observed in 13 unique cancer types, including historically treatment-refractory tumor types such as cholangiocarcinoma, sarcoma, glioma, neuroendocrine carcinoma, and salivary gland carcinomas. Collectively, these data demonstrate that single-agent BRAF inhibition has broader clinical activity than previously recognized. SIGNIFICANCE: These data suggest that BRAF V600 mutations lead to oncogene addiction and are clinically actionable in a broad range of non-melanoma cancers, including tumor types in which RAF inhibition is not currently considered standard of care.See related commentary by Ribas and Lo, p. 640.This article is highlighted in the In This Issue feature, p. 627.

Dual BRAF/MEK blockade restores CNS responses in BRAF-mutant Erdheim-Chester disease patients following BRAF inhibitor monotherapy

Background

Erdheim–Chester disease (ECD), a rare inflammatory myeloid neoplasm, is known to be fundamentally reliant on the constitutive activation of the MAPK signaling pathway in the majority of patients. Consequently, inhibition of the V600E-mutant BRAF kinase has proven to be a safe and efficacious long-term therapeutic strategy for BRAF-mutant ECD patients. Nevertheless, in a subset of patients with CNS disease, the efficacy of long-term treatment may diminish, facilitating suboptimal responses or disease progression.

Methods

We retrospectively describe 3 BRAF-mutant ECD patients whose treatment with Vemurafenib was upgraded to Vemurafenib/Cobimetinib due to either disease progression, insufficient response, or unacceptable toxicity. CNS response to therapy was evaluated using magnetic resonance imaging (MRI) and extra-cranial disease was monitored using ¹⁸F-fludeoxyglucose positron emission tomography/computed tomography (PET/CT).

Results

Three patients with a mean age of 52.6 years were treated with Vemurafenib for a mean duration of 26.6 months (range: 6–52). Monotherapies were upgraded to Vemurafenib/Cobimetinib dual therapy. The combination therapy was administered for a mean duration of 21 months (range: 19–23). All patients exhibited clinical and neurological improvement. Regression of lesions on MRI was noted in 2 patients. Both patients characterized by a PET-avid disease responded to the biological treatment regimen with complete metabolic remissions.

Conclusion

Dual inhibition of BRAF and downstream MEK may be a safe and effective therapeutic strategy for BRAF-mutant ECD patients for whom BRAF inhibitor therapy proved insufficient and as such appropriate for the long-term management of CNS disease in ECD.

The unique burden of rare cancer caregiving: caregivers of patients with Erdheim-Chester disease

Research examining the experience of informal caregivers (ICs) for patients with rare cancers is limited. This was a mixed-methods pilot study of 14 ICs for patients with Erdheim-Chester disease (ECD), an ultra-rare neoplasm. Participants were predominantly female and over half provided at least 60% of their loved one's care. Participants completed measures of the impact of caregiving, caregiver burden, unmet needs, quality of life, anxiety, and depression. Participants reported substantial impact of caregiving, including limiting (50%) or discontinuing (21%) paid employment, and exhausting financial savings (43%). ICs reported a moderate level of burden with five (38%) reporting risk for burnout. While participants reported anxiety (64%) and depression (14%), their overall quality of life was favorable. Semi-structured interviews highlighted factors related to the distress and isolation of navigating a rare cancer. ECD ICs report burden and distress shaped by the experience of providing care for a patient with a rare cancer.

Activating mutations in CSF1R and additional receptor tyrosine kinases in histiocytic neoplasms

Histiocytoses are clonal hematopoietic disorders frequently driven by mutations in BRAF and MEK1/2 kinases. Currently, however, the developmental origins of histiocytoses in patients are not well understood, and clinically meaningful therapeutic targets outside of BRAF and MEK are undefined. Here we uncover activating mutations in CSF-1R, as well as rearrangements in RET and ALK which confer dramatic responses to selective inhibition of RET (selpercatinib) and crizotinib, respectively, in histiocytosis patients.

BRAF V600E mutation in Juvenile Xanthogranuloma family neoplasms of the central nervous system (CNS-JXG): a revised diagnostic algorithm to include pediatric Erdheim-Chester disease

The family of juvenile xanthogranuloma family neoplasms (JXG) with ERK-pathway mutations are now classified within the "L" (Langerhans) group, which includes Langerhans cell histiocytosis (LCH) and Erdheim Chester disease (ECD). Although the BRAF V600E mutation constitutes the majority of molecular alterations in ECD and LCH, only three reported JXG neoplasms, all in male pediatric patients with localized central nervous system (CNS) involvement, are known to harbor the BRAF mutation. This retrospective case series seeks to redefine the clinicopathologic spectrum of pediatric CNS-JXG family neoplasms in the post-BRAF era, with a revised diagnostic algorithm to include pediatric ECD. Twenty-two CNS-JXG family lesions were retrieved from consult files with 64% (n = 14) having informative BRAF V600E mutational testing (molecular and/or VE1 immunohistochemistry). Of these, 71% (n = 10) were pediatric cases (≤18 years) and half (n = 5) harbored the BRAF V600E mutation. As compared to the BRAF wild-type cohort (WT), the BRAF V600E cohort had a similar mean age at diagnosis [BRAF V600E: 7 years (3-12 y), vs. WT: 7.6 years (1-18 y)] but demonstrated a stronger male/female ratio (BRAF V600E: 4 vs WT: 0.67), and had both more multifocal CNS disease ( BRAFV600E: 80% vs WT: 20%) and systemic disease (BRAF V600E: 40% vs WT: none). Radiographic features of CNS-JXG varied but typically included enhancing CNS mass lesion(s) with associated white matter changes in a subset of BRAF V600E neoplasms. After clinical-radiographic correlation, pediatric ECD was diagnosed in the BRAF V600E cohort. Treatment options varied, including surgical resection, chemotherapy, and targeted therapy with BRAF-inhibitor dabrafenib in one mutated case. BRAF V600E CNS-JXG neoplasms appear associated with male gender and aggressive disease presentation including pediatric ECD. We propose a revised diagnostic algorithm for CNS-JXG that includes an initial morphologic diagnosis with a final integrated diagnosis after clinical-radiographic and molecular correlation, in order to identify cases of pediatric ECD. Future studies with long-term follow-up are required to determine if pediatric BRAF V600E positive CNS-JXG neoplasms are a distinct entity in the L-group histiocytosis category or represent an expanded pediatric spectrum of ECD.

New model of care for patients with central nervous system cancers

87

Background: Patients (pts) with primary or metastatic central nervous system (CNS) cancers often have multiple physical, psychosocial, and spiritual needs. Likewise, neurological impairments can transform pts’ relationship dynamics with caregivers. These issues, along with prognosis and end of care planning, are difficult to address within a single outpatient oncology clinic. Methods: The Neurological Multidisciplinary Care Clinic (MdCC) at Memorial Sloan Kettering Cancer Center was a pilot study from 8/2017 to 6/2019 to foster a new model of care for complex pts with CNS cancers to identify and address their needs. Twice a month between 8/2017- 6/2019, a team comprised of a neurologist, nurse, physiatrist (RM), physical therapist, social worker (SW), case manager (CM), dietitian (RD), and chaplain (C) saw patients with neurological deficits and KPS ≤80. Within a 3 hour-visit, providers rotated in to see patients and their caregivers. Since 11/2017 participants completed validated surveys on unmet needs, financial strain, and home equipment prior to their visit, and satisfaction surveys afterward. Descriptive statistics were used to analyze results. Results: Eighty-two pts with advanced cancer were seen: 40 were female, median age 59. Of these 82 pts, 66 had primary CNS cancers, predominantly high-grade glioma/glioblastoma (79%). Over 60% had never seen a CM, RM, RD or C prior to MdCC. Seventy-eight pts (95%) received symptom management recommendations. Prognosis/coping with cancer was discussed with 75 pts (91%) which increased signed health care proxy forms by 16% and DNR orders by 6% at time or within a month post-MdCC. New/updated physical therapy was ordered for 50 pts (61%), orthotics for 10 (12%), and new equipment for 14 (17%). Forty-nine pts completed a satisfaction survey: of these, 96% were highly satisfied, and would recommend MdCC to others. Conclusions: Pts’/caregivers’ unmet needs were effectively identified and addressed within a single MdCC visit. The presence of several providers through MdCC allows for the assessment of pts’/caregivers’ needs and coping skills in real time. The MdCC also facilitates discussing pts’ goals of care, assessing their support system, and implementing a safe patient-centered plan of care.

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

Background

Central retinal vein occlusion (CRVO) is a visually threatening event that has rarely been observed in patients taking MEK1/2 inhibitors and that may necessitate permanent discontinuation of a potentially efficacious therapy. We investigated the clinical characteristics of CRVO in patients on mitogen-activated protein kinase kinase (MEK) inhibition to better understand their predisposing factors and clinical course.

Case Series

This was a single-center, retrospective cohort study (between December 2006 and September 2018). Three of 546 patients enrolled in 46 prospective trials involving treatment with MEK inhibitors at Memorial Sloan Kettering Cancer Center were identified as having CRVO. Clinical examination and course, multimodal ophthalmic imaging, and serum laboratory results (including homocysteine levels and genetic variants of methylene tetrahydrofolate reductase [MTHFR]) were reviewed for the 3 affected patients. All 3 patients with MEK inhibitor-associated CRVO had elevated serum homocysteine and gene variants of MTHFR (1 homozygous for A1298C, 1 heterozygous for A1298C, and 1 homozygous for C677T). Following intravitreous injections of anti-VEGF and discontinuation of drug, all patients regained vision to their baseline.

Discussion

MEK inhibitor-associated CRVO is a rare event which can exhibit visual recovery after drug cessation and intravitreous anti-VEGF injections. In this cohort, it was associated with hyperhomocysteinemia and genetic mutations in MTHFR, suggesting a potential role for hyperhomocysteinemia screening prior to initiation of MEK inhibitor therapy.

Cobimetinib-induced "dropped head syndrome" and subsequent disease management in an Erdheim-Chester patient

Our rechallenge of cobimetinib in an Erdheim-Chester Disease (ECD) patient for the rare adverse effect, "dropped head syndrome," with a previously unexplored cobimetinib regimen was successful. Similar to other experiences with targeted agents in ECD, dosing of cobimetinib may vary to mitigate toxicity without impairing efficacy.