Case report of selumetinib as a novel therapy in a neurofibromatosis type 2-associated ependymoma

We report partial response (PR) to novel therapy with selumetinib in a patient with neurofibromatosis type 2 (NF2). A 25-year-old male presented with bilateral vestibular schwannomas, spinal cord intramedullary ependymomas, cranial and spinal meningiomas, spinal nerve root mixed schwannoma-neurofibromas, and peripheral nerve sheath tumors. He tested negative for germline NF2, SWItch/sucrose non-fermentable-related matrix-associated actin-dependent regulator of chromatin subfamily B member 1 (SMARCB1), and leucine zipper-like transcription regulator 1 (LZTR1) mutations. Molecular analysis of a resected cervical spine schwannoma-neurofibroma demonstrated an isolated somatic SMARCB1 mutation. Due to progression of all tumors, he was treated medically with both everolimus (10 mg/day) and selumetinib (25 mg/kg twice a day), but he rapidly transitioned to selumetinib monotherapy due to everolimus toxicity. 3 months of treatment resulted in PR in one spinal ependymoma and stable disease in other tumors. This PR was quantified by the differences in units of intensity in pre- and post-treatment magnetic resonance image. To the best of our knowledge, this is the first reported case for using selumetinib in NF2-associated tumors or ependymomas.

Clinical and Genetic Analysis of Metastatic Prostate Cancer to the Central Nervous System: A Single-Institution Retrospective Experience

BACKGROUND

Prostate cancer (PC) rarely metastasizes to the central nervous system (CNS). In this retrospective single-institution study at a tertiary cancer center, we aimed to evaluate the clinical and genetic characteristics of advanced PC patients with CNS metastases.

PATIENTS AND METHODS

Between January 2010 and March 2020, 12 out of 579 patients with extracranial metastatic PC were identified to have CNS metastases based on imaging, including six patients with brain metastases (BMs), five patients with dural metastases, and one unknown. These patients were followed up through March 2022. Clinical data were compared to the overall cohort of patients evaluated at our cancer center during that decade. Genetics information was also analyzed for the patients with available data via cell-free DNA (cfDNA) blood samples.

RESULTS

Median time from development of extracranial metastatic disease to development of CNS metastases was 5.5 years (95% CI, 1.8-7.0). Median overall survival (mOS) from diagnosis of CNS metastases was 6.1 months (95% CI, 5.8-8.2). Notably, there was no significant difference in mOS after development of extracranial metastases in patients with CNS metastases (6.4 years; 95% CI, 4.6-7.9) compared to the patients without known CNS metastases (5.2 years; 95% CI, 4.6-5.7) (P = .91). For the cohort with CNS metastases, nine patients had germline testing and seven patients had somatic testing via cfDNA.

CONCLUSION

PC patients with CNS metastases did not often die from a neurological cause. With advancing therapies, the overall prognosis of metastatic PC continues to improve, and CNS metastases will become more common.

LPTO-09. INTRATHECAL TOPOTECAN FOR LEPTOMENINGEAL METASTASIS IN SOLID TUMORS: THE MD ANDERSON EXPERIENCE

BACKGROUND: Leptomeningeal metastasis (LM) is a devastating complication of cancer resulting in progressive neurologic decline. Although intrathecal (IT) methotrexate and cytarabine are commonly used for solid tumor LM, we routinely use IT topotecan due to previously demonstrated similar efficacy and modest side effect profile. We report updated data on our experience. METHODS: We reviewed clinical records of patients with solid tumor LM treated with IT topotecan at MD Anderson Cancer Center from 2008–2018. Patient characteristics and course were summarized by descriptive statistics. Overall survival (OS) was estimated with Kaplan-Meier, and the association of KPS with OS evaluated with log-rank test. RESULTS: 138 patients were treated with IT topotecan. The median age was 54 years (range, 22–76), 81% were female. Breast cancer (62%) was the most common primary, then lung (21%), melanoma (4%). Median time from primary diagnosis to LM was 3.4 (range, 0.07–25.2) years. LM was diagnosed by CSF cytology alone in 8 (6%), MRI alone in 21 (15%), CSF+MRI in 108 (78%). Patients most commonly presented with headache (39%) or sensory changes (18%), and had a median KPS of 80 (range, 60–100). 66% had prior/concurrent brain metastasis. 71 patients (52%) received WBRT following LM diagnosis. 41% had adverse effects, most commonly nausea/vomiting (22%) and headache (20%). The majority were grade 1 (63%); 7 were grade 4 (2 Ommaya malfunctions and 5 infections). Patients received a median of 9 (range, 1–79) doses, most stopped due to CNS progression (42%). Median OS was 6.5 months (95% CI 4.7, 7.8). OS was 3.8 mos with KPS ≤70, vs. 7.5 mos with KPS >70 (p< 0.001). CONCLUSIONS: IT topotecan has a modest side effect profile. Patients with higher functional status at diagnosis had significantly better survival. This study supports the continued use of IT topotecan as a well-tolerated option for LM.

LPTO-08. INTRATHECAL TRASTUZUMAB PLUS/MINUS IT TOPOTECAN FOR PATIENTS WITH HER2+ BREAST CANCER AND LEPTOMENINGEAL METASTASIS

BACKGROUND: Leptomeningeal metastasis (LM) is an aggressive complication of cancer. No standard therapies exist, although at our institution we commonly use IT topotecan in good-risk patients. We report our experience in patients with HER2+ breast cancer (BC) LM treated with intrathecal (IT) trastuzumab +/- IT topotecan. METHODS: We retrospectively reviewed records of patients managed with IT trastuzumab at MD Anderson Cancer Center from 2016–2019. Demographics, clinical course, and outcomes data (Kaplan-Meier) were collected and analyzed. RESULTS: 14 female patients (median age 49, range 33–67) with HER2+ BC (29% hormone receptor (HR) positive, 71% negative) were treated with IT trastuzumab (titrated to 40 mg -100 mg/week); 8 (57%) received concurrent IT topotecan. LM diagnosis was made in 64% by MRI alone, and 36% by both MRI and CSF cytology; 79% had brain metastases (BM), and of those, 55% (6/11) had active BM at LM diagnosis; 57% received WBRT prior to initiation of IT therapy. Median KPS was 90 (range, 60–100). Of those with initially positive cytology, 50% (4/8) converted to negative during treatment. MRI findings improved in 79%; 79% were symptomatic at diagnosis (most commonly ataxia, cranial neuropathy, headache); 70% (7/10) had symptom improvement on IT therapy. The only IT-associated symptom reported was mild nausea that occurred in 29%. Median time from diagnosis of metastatic BC was 10.7 mos. (range 0–83 mos); 36% had active extra-CNS disease and 86% received concurrent systemic therapy; 57% underwent change in systemic therapy during IT treatment; 91% were progression-free at 6 months, 32% at 24 months. Median overall survival from LM diagnosis was 24.7 months (95% CI 10.7, NR). CONCLUSIONS: IT trastuzumab is a safe and promising therapy for patients with HER2+ BC and LM. Dual IT therapy with trastuzumab and topotecan was well-tolerated and warrants further investigation in a larger study.

Neuromuscular complications of immune checkpoint inhibitor therapy

Immune checkpoint inhibitor (ICPI) therapy unleashes the body's natural immune system to fight cancer. ICPIs improve overall cancer survival, however, the unbridling of the immune system may induce a variety of immune-related adverse events. Neuromuscular immune complications are rare but they can be severe. Myasthenia gravis and inflammatory neuropathy are the most common neuromuscular adverse events but a variety of others including inflammatory myopathy are reported. The pathophysiologic mechanism of these autoimmune disorders may differ from that of non-ICPI-related immune diseases. Accordingly, while the optimal treatment for ICPI-related neuromuscular disorders generally follows a traditional paradigm, there are important novel considerations in selecting appropriate immunosuppressive therapy. This review presents 2 new cases, a summary of neuromuscular ICPI complications, and an approach to the diagnosis and treatment of these disorders. Muscle Nerve, 2018.