LC3-associated phagocytosis of neutrophils triggers tumor ferroptotic cell death in glioblastoma.

Necrosis in solid tumors is commonly associated with poor prognostic but how these lesions expand remains unclear. Studies have found that neutrophils associate with and contribute to necrosis development in glioblastoma by inducing tumor cell ferroptosis through transferring myeloperoxidase-containing granules. However, the mechanism of neutrophilic granule transfer remains elusive. We performed an unbiased small molecule screen and found that statins inhibit neutrophil-induced tumor cell death by blocking the neutrophilic granule transfer. Further, we identified a novel process wherein neutrophils are engulfed by tumor cells before releasing myeloperoxidase-containing contents into tumor cells. This neutrophil engulfment is initiated by integrin-mediated adhesion, and further mediated by LC3-associated phagocytosis (LAP), which can be blocked by inhibiting the Vps34-UVRAG-RUBCN-containing PI3K complex. Myeloperoxidase inhibition or Vps34 depletion resulted in reduced necrosis formation and prolonged mouse survival in an orthotopic glioblastoma mouse model. Thus, our study unveils a critical role for LAP-mediated neutrophil internalization in facilitating the transfer of neutrophilic granules, which in turn triggers tumor cell death and necrosis expansion. Targeting this process holds promise for improving glioblastoma prognosis.

Systematic Review of Cerebrospinal Fluid Biomarker Discovery in Neuro-Oncology: A Roadmap to Standardization and Clinical Application.

Effective diagnosis, prognostication, and management of CNS malignancies traditionally involves invasive brain biopsies that pose significant risk to the patient. Sampling and molecular profiling of cerebrospinal fluid (CSF) is a safer, rapid, and noninvasive alternative that offers a snapshot of the intracranial milieu while overcoming the challenge of sampling error that plagues conventional brain biopsy. Although numerous biomarkers have been identified, translational challenges remain, and standardization of protocols is necessary. Here, we systematically reviewed 141 studies (Medline, SCOPUS, and Biosis databases; between January 2000 and September 29, 2022) that molecularly profiled CSF from adults with brain malignancies including glioma, brain metastasis, and primary and secondary CNS lymphomas. We provide an overview of promising CSF biomarkers, propose CSF reporting guidelines, and discuss the various considerations that go into biomarker discovery, including the influence of blood-brain barrier disruption, cell of origin, and site of CSF acquisition (eg, lumbar and ventricular). We also performed a meta-analysis of proteomic data sets, identifying biomarkers in CNS malignancies and establishing a resource for the research community.

Long-term survival with IDH wildtype glioblastoma: first results from the ETERNITY Brain Tumor Funders' Collaborative Consortium (EORTC 1419).

BACKGROUND: Median survival with glioblastoma remains in the range of 12 months on population levels. Only few patients survive for more than 5 years. Patient and disease features associated with long-term survival remain poorly defined. METHODS: European Organization for Research and Treatment of Cancer (EORTC) 1419 (ETERNITY) is a registry study supported by the Brain Tumor Funders Collaborative in the US and the EORTC Brain Tumor Group. Patients with glioblastoma surviving at least 5 years from diagnosis were identified at 24 sites in Europe, US, and Australia. In patients with isocitrate dehydrogenase (IDH) wildtype tumours, prognostic factors were analysed using the Kaplan-Meier method and the Cox proportional hazards model. A population-based reference cohort was obtained from the Cantonal cancer registry Zurich. RESULTS: At the database lock of July 2020, 280 patients with histologically centrally confirmed glioblastoma (189 IDH wildtype, 80 IDH mutant, 11 incompletely characterised) had been registered. In the IDH wildtype population, median age was 56 years (range 24-78 years), 96 patients (50.8%) were female, 139 patients (74.3%) had tumours with O6-methylguanine DNA methyltransferase (MGMT) promoter methylation. Median overall survival was 9.9 years (95% confidence interval [95% CI] 7.9-11.9). Patients without recurrence experienced longer median survival (not reached) than patients with one or more recurrences (8.92 years) (p < 0.001) and had a high rate (48.8%) of MGMT promoter-unmethylated tumours. CONCLUSIONS: Freedom from progression is a powerful predictor of overall survival in long-term survivors with glioblastoma. Patients without relapse often have MGMT promoter-unmethylated glioblastoma and may represent a distinct subtype of glioblastoma.

Cancer stem cell assay-guided chemotherapy improves survival of patients with recurrent glioblastoma in a randomized trial.

Therapy-resistant cancer stem cells (CSCs) contribute to the poor clinical outcomes of patients with recurrent glioblastoma (rGBM) who fail standard of care (SOC) therapy. ChemoID is a clinically validated assay for identifying CSC-targeted cytotoxic therapies in solid tumors. In a randomized clinical trial (NCT03632135), the ChemoID assay, a personalized approach for selecting the most effective treatment from FDA-approved chemotherapies, improves the survival of patients with rGBM (2016 WHO classification) over physician-chosen chemotherapy. In the ChemoID assay-guided group, median survival is 12.5 months (95% confidence interval [CI], 10.2-14.7) compared with 9 months (95% CI, 4.2-13.8) in the physician-choice group (p = 0.010) as per interim efficacy analysis. The ChemoID assay-guided group has a significantly lower risk of death (hazard ratio [HR] = 0.44; 95% CI, 0.24-0.81; p = 0.008). Results of this study offer a promising way to provide more affordable treatment for patients with rGBM in lower socioeconomic groups in the US and around the world.

Temporal radiographic and histological study of necrosis development in a mouse glioblastoma model.

Tumor necrosis is a poor prognostic marker in glioblastoma (GBM) and a variety of other solid cancers. Accumulating evidence supports that necrosis could facilitate tumor progression and resistance to therapeutics. GBM necrosis is typically first detected by magnetic resonance imaging (MRI), after prominent necrosis has already formed. Therefore, radiological appearances of early necrosis formation and the temporal-spatial development of necrosis alongside tumor progression remain poorly understood. This knowledge gap leads to a lack of reliable radiographic diagnostic/prognostic markers in early GBM progression to detect necrosis. Recently, we reported an orthotopic xenograft GBM murine model driven by hyperactivation of the Hippo pathway transcriptional coactivator with PDZ-binding motif (TAZ) which recapitulates the extent of GBM necrosis seen among patients. In this study, we utilized this model to perform a temporal radiographic and histological study of necrosis development. We observed tumor tissue actively undergoing necrosis first appears more brightly enhancing in the early stages of progression in comparison to the rest of the tumor tissue. Later stages of tumor progression lead to loss of enhancement and unenhancing signals in the necrotic central portion of tumors on T1-weighted post-contrast MRI. This central unenhancing portion coincides with the radiographic and clinical definition of necrosis among GBM patients. Moreover, as necrosis evolves, two relatively more contrast-enhancing rims are observed in relationship to the solid enhancing tumor surrounding the central necrosis in the later stages. The outer more prominently enhancing rim at the tumor border probably represents the infiltrating tumor edge, and the inner enhancing rim at the peri-necrotic region may represent locally infiltrating immune cells. The associated inflammation at the peri-necrotic region was further confirmed by immunohistochemical study of the temporal development of tumor necrosis. Neutrophils appear to be the predominant immune cell population in this region as necrosis evolves. This study shows central, brightly enhancing areas associated with inflammation in the tumor microenvironment may represent an early indication of necrosis development in GBM.

Myxopapillary Ependymoma with Anaplastic Features: A Case Series and Review of the Literature.

BACKGROUND: Myxopapillary ependymomas (MPEs) with anaplastic features are rarely reported, with only 21 cases identified to date, and long-term recurrence is rarely presented. A case series is presented to expand understanding of this disease by describing 3 unique cases, including 2 that arose from MPE after a prolonged clinical course. METHODS: A literature review was performed, and 3 cases of MPE with anaplastic features from our institution were included. RESULTS: Patient 1 was a 13-year-old boy who presented with an avidly enhancing intradural lumbar mass. On gross total resection, the tumor was found to be a solid mass with areas of myxopapillary architecture and MIB-1 (Ki-67) index of 12%. Patient 2 was a woman who initially presented at age 22 with a lumbosacral tumor that was treated with surgery and radiation. A recurrent tumor was resected at age 24. At age 50, the patient presented with a large heterogeneous exophytic mass in the sacrum extending into the presacral space and Ki-67 index of 8%. This was treated with complete resection. Patient 3 was a man who initially presented at age 35 with a lower thoracic, upper lumbar mass at L2 extending into the sacrum. Following resection and radiation, a metastatic focus followed an indolent course until causing pain at the age of 48. Ki-67 index was 16%. CONCLUSIONS: The presented cases of MPE with anaplastic features make a total of 24 cases on record in the medical literature and demonstrate 2 examples of late recurrence.

A phase I study of the WT2725 dosing emulsion in patients with advanced malignancies.

WT2725 is a Wilms' tumor gene 1 (WT1)-derived-oligopeptide vaccine designed to induce WT1-specific cytotoxic T-lymphocytes against WT1+ tumors in human leukocyte antigen (HLA)-A*0201+ and/or HLA-A*0206+ patients. Here, we report the results of a phase I study of WT2725. In this phase I, open-label, dose-escalation and expansion two-part study, the WT2725 dosing emulsion was administered as a monotherapy to patients with advanced malignancies known to overexpress WT1, including glioblastoma. In part 1, 44 patients were sequentially allocated to four doses: 0.3 mg (n = 5), 0.9 mg (n = 5), 3 mg (n = 6), and 9 mg (n = 28). In part 2, 18 patients were allocated to two doses: 18 mg (n = 9) and 27 mg (n = 9). No dose-limiting toxicities were observed, so the maximum tolerated dose was not reached. Median progression-free survival was 58 (95% confidence interval [CI] 56-81) days (~ 2 months) across all patients with solid tumors; median overall survival was 394 days (13.0 months) (95% CI 309-648). Overall immune-related response rate in solid tumor patients was 7.5% (95% CI 2.6-19.9); response was most prominent in the glioblastoma subgroup. Overall, 62.3% of patients were considered cytotoxic T-lymphocyte responders; the proportion increased with increasing WT2725 dosing emulsion dose. WT2725 dosing emulsion was well tolerated. Preliminary tumor response and biological marker data suggest that WT2725 dosing emulsion may exert antitumor activity in malignancies known to overexpress the WT1 protein, particularly glioblastoma, and provide a rationale for future clinical development.Trial registration: NCT01621542.

Spontaneous Hip Dislocation Complicating the Management of Malignant Peripheral Nerve Sheath Tumor Arising Within a Plexiform Neurofibroma.

Neurofibromatosis type 1 (NF1) is one of the most common inherited neurological disorders. It can cause plexiform neurofibromas, leading to diffuse enlargement of a nerve or nerves within the body. There are benign in general, however, can cause significant symptoms due to their size, including bony erosion, pain, and joint instability. Unfortunately, they also have the capacity to become malignant by internal transformation into a malignant peripheral nerve sheath tumor (MPNST). The case presented here is a 27-year-old male with NF1 that was followed for years with a pelvic girdle plexiform neurofibroma whose course was complicated by transformation to MPNST and a spontaneous hip dislocation. He underwent excision, Girdlestone procedure, chemotherapy, and radiation. Unfortunately, he subsequently developed lung metastases and is part of a clinical trial with an MDM2 inhibitor and pembrolizumab.

VEGF and Immune Checkpoint Inhibition for Prevention of Brain Metastases: Systematic Review and Meta-analysis.

OBJECTIVE: We conducted a systematic review and meta-analysis to investigate the role of VEGF inhibitors and immune checkpoint inhibitors (ICIs) in preventing the development of brain metastasis (BMs). METHODS: We searched MEDLINE, EMBASE, Cochrane Database, Google Scholar between January 1, 2000 and June 1, 2020. Included studies were randomized controlled trials (RCTs) of adults with systemic cancer which reported incidence of BMs treated with and without VEGF inhibitors, and observational studies of adults with systemic cancer which reported incidence of BMs treated with and without ICIs (there were no RCTs addressing the ICI question). Pooled relative risks (RR) were computed utilizing a binary random-effects model. RESULTS: A search for VEGF and incidence of new BMs revealed 7 studies (6212 patients with breast, colon and non-small cell lung cancer). Meta-analysis showed a lower incidence of new BMs compared to control (RR 0.71, 95% CI: 0.56-0.89, p=0.003). A search for ICIs and incidence of new BMs yielded 8 studies (732 patients with non-small cell lung cancer or metastatic melanoma) where ICIs were used as an adjunct to radiosurgery. Meta-analysis showed a lower incidence of out-of-treatment-field BMs with ICI inhibitors compared to controls at 1 year (RR 0.65, 95% CI: 0.49-0.88, p=0.005). The overall GRADE score for the evidence evaluating the role of bevacizumab and immune checkpoint inhibitors was high and moderate, respectively. CONCLUSION: VEGF and immune checkpoint inhibitors may have a role in prophylaxis against brain metastases in patients with solid tumors.

Neutrophil-induced ferroptosis promotes tumor necrosis in glioblastoma progression.

Tumor necrosis commonly exists and predicts poor prognoses in many cancers. Although it is thought to result from chronic ischemia, the underlying nature and mechanisms driving the involved cell death remain obscure. Here, we show that necrosis in glioblastoma (GBM) involves neutrophil-triggered ferroptosis. In a hyperactivated transcriptional coactivator with PDZ-binding motif-driven GBM mouse model, neutrophils coincide with necrosis temporally and spatially. Neutrophil depletion dampens necrosis. Neutrophils isolated from mouse brain tumors kill cocultured tumor cells. Mechanistically, neutrophils induce iron-dependent accumulation of lipid peroxides within tumor cells by transferring myeloperoxidase-containing granules into tumor cells. Inhibition or depletion of myeloperoxidase suppresses neutrophil-induced tumor cell cytotoxicity. Intratumoral glutathione peroxidase 4 overexpression or acyl-CoA synthetase long chain family member 4 depletion diminishes necrosis and aggressiveness of tumors. Furthermore, analyses of human GBMs support that neutrophils and ferroptosis are associated with necrosis and predict poor survival. Thus, our study identifies ferroptosis as the underlying nature of necrosis in GBMs and reveals a pro-tumorigenic role of ferroptosis. Together, we propose that certain tumor damage(s) occurring during early tumor progression (i.e. ischemia) recruits neutrophils to the site of tissue damage and thereby results in a positive feedback loop, amplifying GBM necrosis development to its fullest extent.

Management of low-grade glioma: a systematic review and meta-analysis.

BACKGROUND: Optimum management of low-grade gliomas remains controversial, and widespread practice variation exists. This evidence-based meta-analysis evaluates the association of extent of resection, radiation, and chemotherapy with mortality and progression-free survival at 2, 5, and 10 years in patients with low-grade glioma. METHODS: A quantitative systematic review was performed. Inclusion criteria included controlled trials of newly diagnosed low-grade (World Health Organization Grades I and II) gliomas in adults. Eligible studies were identified, assigned a level of evidence for every endpoint considered, and analyzed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The relative risk of mortality and of progression at 2, 5, and 10 years was calculated for patients undergoing resection (gross total, subtotal, or biopsy), radiation, or chemotherapy. RESULTS: Gross total resection was significantly associated with decreased mortality and likelihood of progression at all time points compared to subtotal resection. Early radiation was not associated with decreased mortality; however, progression-free survival was better at 5 years compared to patients receiving delayed or no radiation. Chemotherapy was associated with decreased mortality at 5 and 10 years in the high-quality literature. Progression-free survival was better at 5 and 10 years compared to patients who did not receive chemotherapy. In patients with isocitrate dehydrogenase 1 gene (IDH1) R132H mutations receiving chemotherapy, progression-free survival was better at 2 and 5 years than in patients with IDH1 wild-type gliomas. CONCLUSIONS: Results from this review, the first to quantify differences in outcome associated with surgery, radiation, and chemotherapy in patients with low-grade gliomas, can be used to inform evidence-based management and future clinical trials.

MLN8237 treatment in an orthoxenograft murine model for malignant peripheral nerve sheath tumors.

OBJECTIVEMalignant peripheral nerve sheath tumors (MPNSTs) are soft-tissue sarcomas arising from peripheral nerves. MPNSTs have increased expression of the oncogene aurora kinase A, leading to enhanced cellular proliferation. This makes them extremely aggressive with high potential for metastasis and a devastating prognosis; 5-year survival estimates range from a dismal 15% to 60%. MPNSTs are currently treated with resection (sometimes requiring limb amputation) in combination with chemoradiation, both of which demonstrate limited effectiveness. The authors present the results of immunohistochemical, in vitro, and in vivo analyses of MLN8237 for the treatment of MPNSTs in an orthoxenograft murine model.METHODSImmunohistochemistry was performed on tumor sections to confirm the increased expression of aurora kinase A. Cytotoxicity analysis was then performed on an MPNST cell line (STS26T) to assess the efficacy of MLN8237 in vitro. A murine orthoxenograft MPNST model transfected to express luciferase was then developed to assess the efficacy of aurora kinase A inhibition in the treatment of MPNSTs in vivo. Mice with confirmed tumor on in vivo imaging were divided into 3 groups: 1) controls, 2) mice treated with MLN8237, and 3) mice treated with doxorubicin/ifosfamide. Treatment was carried out for 32 days, with imaging performed at weekly intervals until postinjection day 42. Average bioluminescence among groups was compared at weekly intervals using 1-way ANOVA. A survival analysis was performed using Kaplan-Meier curves.RESULTSImmunohistochemical analysis showed robust expression of aurora kinase A in tumor cells. Cytotoxicity analysis revealed STS26T susceptibility to MLN8237 in vitro. The group receiving treatment with MLN8237 showed a statistically significant difference in tumor size compared with the control group starting at postinjection day 21 and persisting until the end of the study. The MLN8237 group also showed decreased tumor size compared with the doxorubicin/ifosfamide group at the conclusion of the study (p = 0.036). Survival analysis revealed a significantly increased median survival in the MLN8237 group (83 days) compared with both the control (64 days) and doxorubicin/ifosfamide (67 days) groups. A hazard ratio comparing the 2 treatment groups showed a decreased hazard rate in the MLN8237 group compared with the doxorubicin/ifosfamide group (HR 2.945; p = 0.0134).CONCLUSIONSThe results of this study demonstrate that MLN8237 is superior to combination treatment with doxorubicin/ifosfamide in a preclinical orthoxenograft murine model. These data have major implications for the future of MPNST research by providing a robust murine model as well as providing evidence that MLN8237 may be an effective treatment for MPNSTs.

A phase II trial of tamoxifen and bortezomib in patients with recurrent malignant gliomas.

NF-kB inhibition by bortezomib enhances tamoxifen-induced apoptosis in preclinical glioma models. We conducted a single institution, phase II trial to evaluate efficacy and safety of high dose tamoxifen with bortezomib in adults with recurrent malignant gliomas. The primary endpoint was radiographic response. Concurrent enzyme inducing anticonvulsants and grade ≥2 peripheral neuropathy were exclusion criteria. Patients received tamoxifen (120 mg PO twice daily) and bortezomib (1.3 mg/m2 IV on days 3, 6, 10, 13, 24, 27, 31, and 34) per 6-week cycles. We enrolled 42 patients with anaplastic gliomas (AGs, n = 12) and glioblastomas (GBMs, n = 30), 32 males and 10 females. Median age was 38 years (range 22-65) and 48 years (range 19-68) for AGs and GBMs, respectively. median karnofsky performance status was 90% (range 70-100) for AGs and 80% (range 60-100) for GBMs. Median prior therapies was 3, ranging 1-7. Grade ≥3 toxicities included lymphopenia (4/42), hypophosphatemia (3/42), thromobocytopenia (2/42), and 1/42 with hyponatremia, headache, dyspnea, or DVT. One patient withdrew consent, two were removed for toxicity, and all others discontinued for progression. Among 40 patients evaluable for response, only one achieved stable disease for 3 months; all others progressed rapidly. For AGs and GBMs respectively, median progression-free survival was 5.9 and 5.7 weeks and median overall survival was 25.6 and 14.7 weeks. The study was closed due to poor accrual and therapeutic futility. Combination tamoxifen and bortezomib has no activity in recurrent malignant gliomas. Poor penetration across blood brain barrier of bortezomib likely limited efficacy.

Apparent diffusion coefficient histogram analysis stratifies progression-free and overall survival in patients with recurrent GBM treated with bevacizumab: a multi-center study.

We have tested the predictive value of apparent diffusion coefficient (ADC) histogram analysis in stratifying progression-free survival (PFS) and overall survival (OS) in bevacizumab-treated patients with recurrent glioblastoma multiforme (GBM) from the multi-center BRAIN study. Available MRI's from patients enrolled in the BRAIN study (n = 97) were examined by generating ADC histograms from areas of enhancing tumor on T1 weighted post-contrast images fitted to a two normal distribution mixture curve. ADC classifiers including the mean ADC from the lower curve (ADC-L) and the mean lower curve proportion (LCP) were tested for their ability to stratify PFS and OS by using Cox proportional hazard ratios and the Kaplan-Meier method with log-rank test. Mean ADC-L was 1,209 × 10(-6)mm(2)/s ± 224 (SD), and mean LCP was 0.71 ± 0.23 (SD). Low ADC-L was associated with worse outcome. The hazard ratios for 6-month PFS, overall PFS, and OS in patients with less versus greater than mean ADC-L were 3.1 (95 % confidence interval: 1.6, 6.1; P = 0.001), 2.3 (95 % CI: 1.3, 4.0; P = 0.002), and 2.4 (95 % CI: 1.4, 4.2; P = 0.002), respectively. In patients with ADC-L <1,209 and LCP >0.71 versus ADC-L >1,209 and LCP <0.71, there was a 2.28-fold reduction in the median time to progression, and a 1.42-fold decrease in the median OS. The predictive value of ADC histogram analysis, in which low ADC-L was associated with poor outcome, was confirmed in bevacizumab-treated patients with recurrent GBM in a post hoc analysis from the multi-center (BRAIN) study.

Disseminated strongyloidiasis complicating glioblastoma therapy: a case report.

Strongyloides stercoralis is an intestinal parasite that can cause fatal opportunistic infections in immunocompromised patients. Here we report an immunocompromised patient with glioblastoma who developed disseminated strongyloidiasis 6 weeks after completion of standard radiotherapy and concurrent temozolomide chemotherapy. She was effectively treated with albendazole and ivermectin. Strongyloidiasis should be considered in patients being treated for glioma who have lived or traveled to high risk areas and developed gram negative sepsis, along with gastrointestinal or respiratory symptoms, skin rash or SIADH.

Neuroleukemiosis: case report of leukemic nerve infiltration in acute lymphoblastic leukemia.

We describe a patient in remission from acute lymphoblastic leukemia who developed a painless common peroneal neuropathy. Magnetic resonance imaging (MRI) revealed nerve thickening and enhancement, while a positron emission tomography (PET) scan demonstrated increased fluorodeoxyglucose uptake in a large segment of the neurovascular bundle, suggesting peripheral nerve infiltration. Both findings resolved following treatment with chemotherapy that crossed the blood-nerve barrier. In selected patients presenting with peripheral neuropathy, MRI and PET scan can be helpful in the diagnosis of peripheral nerve infiltration.

Prevention of gestational diabetes by metformin plus diet in patients with polycystic ovary syndrome.

OBJECTIVE: To prospectively assess whether metformin diet safely provides primary and secondary prevention of gestational diabetes (GD). DESIGN: Assess development of GD on metformin diet. SETTING: Outpatient clinical research center. PATIENT(S): One hundred forty-two nondiabetic women with polycystic ovary syndrome (PCOS) who had at least one live-birth (LB) pregnancy on metformin diet (172 pregnancies, 180 LBs). INTERVENTION(S): Women were given 26% protein, 44% carbohydrate diets, without calorie restriction during pregnancy. Metformin (2-2.55 g/d) was given preconception, through pregnancy. MAIN OUTCOME MEASURE(S): Development of GD. RESULT(S): On metformin, GD developed in 12 (7%) of 172 LB pregnancies. Forty-seven women had at least one previous LB pregnancy (n = 64) without metformin, with GD developing in 19 (30%). Subsequently, on metformin, these 47 women had 50 LB pregnancies, developing GD in 6 (12%), which was a statistically significant difference. Of 15 women who had previous GD without metformin, GD developed in 5 (31%) of 16 subsequent pregnancies on metformin. Of 32 women who were previously free of GD without metformin, GD developed in 1 (3%) of 34 subsequent pregnancies on metformin. Previous GD without metformin was the only statistically significant explanatory variable for current GD on metformin. CONCLUSION(S): Metformin diet during pregnancy in women with PCOS facilitates primary and secondary prevention of GD.

Sustainability of 8% weight loss, reduction of insulin resistance, and amelioration of atherogenic-metabolic risk factors over 4 years by metformin-diet in women with polycystic ovary syndrome.

In 74 women with polycystic ovary syndrome, treated for 4 years with metformin (MET) and diet, we prospectively assessed whether, and to what degree, weight loss, reduction of insulin resistance, and amelioration of coronary heart disease risk factors could be sustained. We hypothesized that response to MET-diet would not differ by pretreatment body mass index (BMI) classes <25 (normal), > or =25 to <30 (overweight), > or =30 to <40 (obese), and > or =40 (extremely obese). [table: see text] Metformin-diet was successful in producing stable approximately 8% weight reduction for all 4 years (trend P < .0001). Percentage of reductions in weight on MET-diet was significant (P < .05) and did not differ among the 3 highest BMI categories (> or =40, > or =30 to <40, > or =25 to <30), but were not significant in the normal-weight category (BMI, <25). On MET-diet, median homeostasis model assessment of insulin resistance (HOMA-IR) was 33% lower than entry at 1 year, 50% at 2 years, 51% at 3 years, and 50% at 4 years (trend, P < .0001). On MET-diet, median low-density lipoprotein cholesterol (LDL-C) was 6% lower than entry at year 1, 6% at year 2, 7% at year 3, and 11% at year 4 (trend P < .0001). On MET-diet, median high-density lipoprotein cholesterol (HDL-C) was 3% higher than entry at year 2, 8% higher at year 3, and 11% higher at year 4 (trend P < .0001). Percentage of reductions in HOMA-IR, LDL-C, triglyceride, and systolic blood pressure, and increments in HDL-C did not differ (P > .1) in the 4 BMI categories. By stepwise regression, weight loss was a significant (P < or = .01) positive explanatory variable for reduction in HOMA-IR for all 4 follow-up years. Metformin-diet in women with polycystic ovary syndrome effectively and safely reduces weight and LDL-C while raising HDL-C, and maintains these outcomes stable over 4 years.