51 Clinical Trials for Various Conditions
Based on the clinical activity of both selumetinib and cabozantinib as monotherapies in clinical trials, the demonstrated activity of these agents in reduced doses in preclinical studies, and the non-overlapping toxicity profiles, the study will assess the tolerability and efficacy of selumetinib and cabozantinib in combination in participants with NF1 ≥16 years old with progressive and/or symptomatic PN in a phase 1/1b/2 clinical trial. Trial Design Phase 1 This will be an open label, dose escalation phase. Dose level escalation will be determined by a rolling six design. In this design, up to 6 participants can be enrolled at a given dose level and then evaluated for dose limiting toxicity (DLT) within the DLT window. The DLT window is defined as 16 weeks in this study based on the long half-life of cabozantinib and the desire to have maximum confidence about long-term tolerability of the combination prior to proceeding to the next dose level. Phase 1b Once the recommended phase 2 dose has been determined in phase 1, an expanded cohort of 12 participants will be enrolled in phase 1b portion of the study. Phase 2 This will be an open label, single-arm phase using the recommended phase 2 dose.
This study in adolescent participants with NF1 who have inoperable PN is designed to evaluate the effect of a low fat meal on steady state selumetinib exposure; to assess the effect on GI tolerability when selumetinib is dosed under fed and fasted conditions; and potentially, to confirm an appropriate dosing recommendation of selumetinib with a low fat meal that maintains efficacy with acceptable safety. These results may support labelling statements with regard to posology and food.
A global study to demonstrate the effectiveness of selumetinib in participants with NF1 who have symptomatic, inoperable plexiform neurofibromas.
Background: People with Neurofibromatosis type 1 (NF1) have an increased risk of developing plexiform neurofibromas (PNs). PNs are tumors that form in the tissue. They can form anywhere in the body. They can become visible and cause deformations. Researchers want to see if selumetinib changes how PNs look in people with NF1. They also want to test a rating system for the visibility of these tumors. Objective: To see if treatment with selumetinib can improve the appearance of visible PNs in people with NF1, as determined by people who are/are not familiar with NF1. Eligibility: People with NF1 who have one or more visible PNs and have been enrolled in study 11C0161 or 08C0079. Clinicians and non-clinicians with and without experience in NF1 are also needed to serve as raters. Design: Participants are people with NF1 who had photos taken on study 11C0161 or 08C0079. Raters are people who will evaluate the PNs in the photos. They will rate the tumors on a scale from 1 to 10, from less to most visible. Participants medical records will be reviewed. Their photos will be shown to 28 raters. Raters will fill out a survey about their demographics, place of work, and if they are familiar with NF1. They will view sample photos to learn how PNs look and how to rate PNs. Raters will view photos of PNs taken before and after selumetinib treatment. They will also view photos of PNs that were not treated. They will rate PNs for up to 40 participants. They will have 1-2 sessions. Each session will last 1 hour....
Background: NF1 is a genetic syndrome. Tumors appear early in life. Many people with NF1 develop PN. These tumors can become an aggressive cancer called MPNST. People with MPNST may benefit from treatment with a MEK inhibitor (MEKi). Researchers want to learn if there is an increased risk of MPNST formation from MEKi treatment in people with NF1. To do this, they will review data that has been collected in NIH NF1 studies. Objective: To describe the characteristics of people who have taken part in NF1 studies at NIH and to compare the risk of MPNST formation in those treated with MEKi or other PN-directed treatment. Eligibility: People with NF1 who were seen at NIH from Jan. 1, 1998, to Jan. 1, 2020. Design: Participants medical records will be reviewed. Participants who opted out of future use of their data will not be included. Demographic data, like sex, race, and date of birth, will be collected. Data about MEKi and non-MEKi treatments will be collected. Clinical data, such as surgery and treatment details, will be collected. The differences between all participants who were seen at NIH for any NF1 related study will be compared. Participants will be put into 4 groups: History of MEKi therapy Treatment with tumor directed therapy other than MEKi Treatment with both MEKi and non-MEKi tumor directed therapies No tumor directed medical therapy Participants with NF1 who were treated for PN with either a MEKi treatment or a non-MEKi treatment will also be compared. The study will last for 3 to 6 months.
This study evaluates mirdametinib (PD-0325901) in the treatment of symptomatic inoperable neurofibromatosis type-1 (NF1)-associated plexiform neurofibromas (PNs). All participants will receive mirdametinib (PD-0325901). Eligible participants may continue in a long-term follow-up phase.
This is a phase II open label study that will evaluate children ≥ 1 year of age and adults with neurofibromatosis type 1 (NF1) and plexiform neurofibromas treated with the MEK inhibitor, binimetinib. The primary objective is to determine if there is an adequate level of disease responsiveness to binimetinib in children and adults with NF1 and inoperable plexiform neurofibromas. The objective response to binimetinib is defined as ≥ 20% decrease in tumor volume reduction by 12 courses.
Background: People with neurofibromatosis 1 (NF1) who have plexiform neurofibromas (pNFs) can have pain that affects their daily lives. This study aims to improve questionnaires that measure their pain, daily living, and physical functioning. Objectives: To examine and improve questionnaires about daily living for people with NF1 and pNFs. Eligibility: People ages 5 and older with NF1 and a pNF Design: Participants will be screened with medical history. This study will have 2 phases. Phase 1 participants will talk about existing pain assessment questionnaires and how pNFs affect their life. They will have group discussions of up to 8 people of a similar age with NF1 and pNFs, or the parents of children with it. These will last about 90 minutes. Children ages 5 to 7 and their parents will have one-on-one meetings instead. These will last about 45 minutes. Discussions will be audiotaped. After the questionnaires have been changed, individual interviews will discuss the new wording, instructions, questions, and electronic format of the new forms. Phase 2 is now complete. Phase 1 participants may be invited to Phase 2. Phase 2 participants will complete the new questionnaires. These may be pen-and-paper or electronic. The questionnaires will take about 30 minutes for adults and teens. Children will work one-on-one with a staff member and may need up to 45 minutes. A small group of participants will be complete the forms twice-in clinic and 1 month later at home. Also, a small group who start a new pain treatment or have a dose increase in their treatment will complete the forms twice-before the treatment change and 1 month later.
Background: - People with neurofibromatosis type I (NF1) and plexiform neurofibroma (PN) tumors often have chronic pain that his hard to control. People usually take medicines for the pain, but they may not work well and might cause side effects. A new strategy called Acceptance and Commitment Training (ACT) may help these people cope with chronic pain. ACT focuses on things like values and living in the moment. Objective: - To see if Acceptance and Commitment Training improves pain coping in people with NF1 pain. Eligibility: - People age 16-34 who have NF1, 1 or more PN tumors, and pain that interferes with their daily functioning. Design: * Participants will be screened with a physical exam, medical history, and questions about their pain. * Participants will fill out questionnaires about their pain and feelings. Their heart rate will be measured via electrocardiogram (ECG). * Participants will be divided into 2 groups randomly. One will wait 8 weeks. * The other will start training right away. * Participants will have 2 two-hour sessions with an ACT trainer. They will learn techniques for setting goals based on personal values and other ways to cope with pain. They will get a workbook and a compact disc (CD) to take home for practice. * Participants will do practice exercises at home between sessions. They will get weekly emails with a practice exercise. They will join video chat sessions via home computer with their trainer. * All participants will return to National Institutes of Health (NIH) after 8 weeks for questionnaires and an ECG. The wait group will then start training. They will return 8 weeks later for questionnaires and an ECG. * Six months later, they will complete questionnaires from home by computer.
Background: Neurofibromatosis type 1 (NF1) is a disorder that can cause plexiform neurofibromas (PNs). These are tumors that grow along nerves. Some PNs cause serious health problems. PNs often can t be operated on because of their large size, location, or number. There are no effective treatments known for people with NF1 and PNs. Researchers want to test if the drug selumetinib (AZD6244 hydrogen sulfate) causes PNs to shrink or slows down their growth. Objectives: To test if selumetinib helps treat PNs. To test how the body handles selumetinib and how it affects peoples symptoms. Eligibility: People ages 18 and older with NF1, with an inoperable PN that causes morbidity or is growing Design: Participants will be screened with: Medical history and physical exam Blood, urine, and heart tests Eye exam MRI: They lie in a machine that takes pictures of the body. PN biopsy: A small piece of the tumor is removed by a large needle. Questionnaires Participants will swallow selumetinib capsules every 12 hours for several 28-day cycles. The capsules are taken with a full glass of water on an empty stomach. Participants may have only water for 2 hours before and 1 hour after each dose. Participants will keep a drug diary. They will continue taking the drug as long as they tolerate it and their disease doesn t progress. Participants will have several visits throughout the study. These will include repeats of the screening tests. Participants will have a final visit after they stop taking selumetinib.
Background: - Some people with cancer have solid tumors. Others have refractory leukemia. This may not go away after treatment. Researchers want to see if a drug called TURALIO(R) can shrink tumors or stop them from growing. Objectives: - To find the highest safe dose and side effects of TURALIO(R). To see if it helps treat certain types of cancer. Eligibility: - People ages 3-35 with a solid tumor or leukemia that has returned or not responded to cancer therapies. Design: * Participants will be screened with: * Medical history * Physical exam * Blood and urine tests * Heart tests * Scans or other tests of the tumor * Participants will take TURALIO(R) as a capsule once daily for a 28-day cycle. They can do this for up to 2 years. * During the study, participants will have many tests and procedures. They include repeats of the screening tests. Participants will keep a diary of symptoms. * Participants with solid tumors will have scans or x-rays. * Participants with leukemia will have blood tests. They may have a bone marrow sample taken. * Some participants may have a biopsy. * When finished taking TURALIO(R), participants will have follow-up visits. They will repeat the screening tests and note side effects.
Background:\<TAB\> - Many people with neurofibromatosis type 1 (NF1) get tumors of the nervous system. Finding malignant tumors early is important for removing them. Researchers want to find ways of doing this with scans and genetic testing. Objectives: - To learn more about neurofibromatosis type 1. Eligibility: - People age 10 and older with NF1 who have a benign tumor or have had a malignant one. Design: * Participants will be screened in another study with medical history, physical exam, and urine and blood tests. They will have a magnetic resonance imaging (MRI) scan. * MRI: Participants will lie on a table that slides into a metal cylinder. They will be in the scanner for 60 90 minutes, lying still for 15 minutes at a time. Participants will get earplugs for the loud sounds. They will get a contrast agent (dye) through a thin plastic tube (catheter) inserted in an arm vein. * As part of their regular care, participants will have: * FDG-PET/CT scan. They will get radioactive glucose (sugar) through a catheter in an arm vein. * \[18F\]-FLT-PET/CT scan. This is like the FDG scan but with a different radioactive chemical. * Biopsy. A piece of tumor tissue is removed with a needle. A piece of tissue from a previous biopsy may also be studied. * Participants may have genetic testing. Blood will be taken. It will be tested along with biopsy samples. Researchers will explain the risks and procedures. They may notify participants if testing shows health problems. * After this study, participants will continue their regular cancer care.
This was a 4-part (Part A, Part B, Part C and Part D), Phase I/IIa, multi-center, open label, study in pediatric subjects with refractory or recurrent tumors. Part A was a repeat dose, dose escalation and expansion phase that identified the recommended phase II dose (RP2D) of trametinib monotherapy. Part B evaluated the preliminary activity of trametinib monotherapy in 4 disease-specific cohorts of subjects. Part C was aimed to determine the safety, tolerability and preliminary activity of the RP2D of trametinib in combination with a limited dose escalation of dabrafenib. Part D evaluated the preliminary activity of trametinib in combination with dabrafenib in 2 disease-specific cohorts of subjects. The overall goal of this trial was to efficiently establish safe, pharmacologically relevant dose of trametinib monotherapy and trametinib in combination with dabrafenib in infants, children and adolescents and determine preliminary activity of trametinib monotherapy and trametinib in combination with dabrafenib in selected recurrent, refractory or unresectable childhood tumors.
This study, "A Phase II Study of Cabozantinib (XL l84) for Plexiform Neurofibromas in Subjects with Neurofibromatosis Type I in Children and Adults diagnosed with Neurofibromatosis Type 1 (NF1) and have a type of tumor called a plexiform neurofibroma (PN). Neurofibromas are tumors that develop from the cells and tissues that cover the nerves. Plexiform neurofibromas can be disfiguring, painful, and life-threatening. These types of tumors typically do not respond well to most treatment approaches such as chemotherapy, radiation, and surgery because of their slow growth and location near vital structures of the body such as nerves, blood vessels, and the airway. The primary objective is to determine the response rate of NF1 patients with plexiform neurofibromas treated with Cabozantinib therapy using MRI scans. The objective response rate to cabozantinib is defined as ≥ 20% reduction in tumor volume at the end of 12 cycles.
THe primary objective is to estimate the response rate at 6 months to Gleevec® in patients with plexiform neurofibromas
This is a pilot study to determine if adults and children with neurofibromatosis type 1 who have plexiform tumors given Sutent® respond to this drug therapy.
The purpose of this Pilot Study is to determine if NF1 patients with plexiform neurofibromas treated with Tasgina® respond to therapy.
This is a second Pilot Study to determine the efficacy of Gleevec® in neurofibromatosis (NF1) patients with plexiform neurofibromas using new response assessment modalities with the secondary goals of assessing Gleevec toxicity, and characterizing markers of response. The rationale for this study arises from the response of human and murine NF1 cells to Gleevec® in vitro, the response of a NF1 patient treated with Gleevec® for airway compression by a plexiform neurofibroma with a dramatic response not previously seen in NF1 therapy, and the experience in 37 NF1 patients treated with Gleevec® in the initial pilot study. Gleevec will be dosed orally with a starting dose of 100 mg twice daily for patients with a BSA \> 1.8 m2 or 55 mg/m2 twice daily for patients with BSA \< 1.8 m2. For patients with a BSA \> 1.8 m2 the dose will increase by increments of 100 mg bid every two weeks as tolerated up to a maximum dose of 400 mg bid. For patients with a BSA \< 1.8 m2 the dose will increase by increments of 55 mg/m2 bid every two weeks as tolerated up to a maximum dose of 220 mg/m2 bid. Treatment will continue for 6 months with an option to continue for 24 months if the patient is deriving a clinical benefit.
Background: Patients with neurofibromatosis type 1 are at increased risk of developing tumors called plexiform neurofibromas (PN) that arise from nerves. These tumors are usually non-cancerous, but they can cause serious medical problems. Sorafenib was recently approved to treat patients with kidney cancer and is now being tested in children with cancer. It affects several pathways thought to be important for the development and growth of PN and may therefore shrink these tumors or slow their growth. Objectives: To determine the highest dose of sorafenib that can safely be given to children and young adults with PN. To identify the side effects of sorafenib in these patients. To study how the body handles sorafenib by measuring the amount of drug in the bloodstream over time To determine how the drug affects blood flow and blood cells and proteins. To determine if sorafenib can shrink or slow the growth of PN. To determine the effects of sorafenib on learning, attention, memory, and quality of life. Eligibility: Patients between 3 and 18 years of age with NF1 who have inoperable PN that can cause significant disability. Design: Patients take sorafenib tablets twice a day in 28-day treatment cycles. They may continue treatment until their tumor grows or they develop unacceptable drug side effects. In this dose escalation study, the dosage is increased with every 3 to 6 children who are enrolled until the highest safe dose is determined. In any case, the dose will not exceed that used in children with cancer. Patients are monitored regularly with physical examinations, blood and urine tests, MRI scans and quality-of-life questionnaires. Patients whose bones are still growing have periodic x-rays of the hips and lower legs to monitor for possible changes in the structure of growing bones. Patients have periodic tests of learning and memory before starting treatment and before cycles 4, 12, 18 and 24. Patients have pharmacokinetic studies to examine how the body handles sorafenib. blood samples are drawn before the first dose of sorafenib and then at 30 minutes, 1 hour, 2 hours, 3 hours, 5 hours, 8 hours, 10 to 12 hours, 24 hours and 30 to 36 hours following the first dose. ...
Plexiform neurofibromas (PN) represent one of the most significant complications of NF1. They are a significant cause of morbidity in neurofibromatosis type 1 (NF1) by causing pain, impaired function, and disfigurement. They may become life-threatening through mechanical compression of vital organs such as the trachea, great vessels, or spinal cord, and may significantly interfere with normal function when located in the extremities or orbit. The only effective therapy for PN is total surgical excision. However, due to local infiltration of normal tissue, gross total resection is usually not feasible, and often PN are completely unresectable due to their location, size, and multiplicity. To date, other therapeutic modalities, including radiotherapy and chemotherapy, have not shown efficacy in PN. In the present study, local photodynamic therapy will be investigated. Photodynamic therapy (PDT) utilizes a drug, called a photosensitizer or photosensitizing agent, and a particular type of light. When photosensitizers are exposed to a specific wavelength of light, they produce a form of oxygen that kills nearby cells. PDT is expected to result in treatment response with shrinkage of tumor. The main purpose of the study is to determine the maximum amount of light that can be safely used with LS11 for PDT in children with plexiform neurofibromas.
Treatment Overview This phase II study will evaluate the activity of sirolimus in children and adults with NF1 and inoperable plexiform neurofibromas that have the potential to cause significant morbidity. The following disease strata will be studied: Stratum 1: Progressive plexiform neurofibroma(s) that have the potential to cause significant morbidity. The endpoint will be time to tumor progression based on volumetric tumor measurements. Stratum 2: Plexiform neurofibromas without documented radiographic progression at trial entry. The endpoint will be radiographic response. As of May 2009, Stratum 2 was closed to enrollment. Stratum 1 is active.
This study is for slow growing tumors called plexiform neurofibromas (PNF) which are a relatively common problem in people with neurofibromatosis type 1 (NF1). These tumors are benign but as they grow, they can become disfiguring as well as disabling or even life threatening. They often cause pain, difficulty using arms or legs because of spinal cord compression, and/or nerve damage. At present, the only available therapy for plexiform neurofibromas is to try to surgically remove as much of the tumor as is possible. Because these tumors grow into the surrounding areas, total surgical resection is often impossible. Most tumors will re-grow after surgery if the entire tumor cannot be removed. To date, other treatments including chemotherapy and radiotherapy have not been able to shrink these tumors. Interferon is a drug that is used for different types of tumors as well as for hepatitis. It has been used in the treatment of plexiform neurofibromas (PNF) with some subjects showing improvement in symptoms and/or a decrease in the size of the tumor. Most subjects had no further growth of their tumor while on the PEG-Intron. The drug used in this study is PEG (pegylated)-Intron. PEG-Intron is a long acting form of interferon which keeps the drug from being broken down in the body for a longer period of time and potentially could be more effective than the short-acting interferon. PEG-Intron has been approved by the Food and Drug Administration (FDA) for the treatment of Hepatitis C. The goals of this study are: 1. To determine how your child's plexiform neurofibroma responds to PEG-Intron when given weekly. 2. To determine the side effects of PEG-Intron when given weekly to participants with plexiform neurofibromas. 3. To evaluate a new method of measuring changes in the size of tumors called volume analysis. This method measures the entire volume of a tumor in three dimensions. The standard method of measuring tumors uses only the length and/or width of the tumor. By studying the different ways of measuring tumors the investigators hope to be able to determine which method is the most accurate and useful.
This study will construct tissue microarrays (TMAs) pertaining to childhood cancer. TMA technology is a recently developed one that allows for evaluating hundreds of tissue samples simultaneously on the DNA, RNA, and protein levels. The goal is to identify a potential molecular signature. Cancer drug discovery is currently focused on identifying drugs targeted at the molecular level. Such drugs would be more selective and specific for proteins and signaling pathways that are directly involved in the origin of tumors. However, the origin of cancer among adults differs from that of cancer diagnosed in children. The overall approach by the pharmaceutical industry in developing drugs is not likely to be aimed at low-incidence cancers, such as childhood cancers. Thus, the researchers in this study propose to create a childhood cancer TMA that include specimens from a wide range of solid tumors that present a poor prognosis for patients. This TMA would in turn be used to identify antibodies and lead to developing molecularly targeted drugs that would reach clinical trials in adults. TMAs are created robotically. Small tissue cores are taken from paraffin-embedded tissue blocks and are implanted into new paraffin blocks. The recipient blocks are then processed to produce several hundred specimens that can be evaluated on a single glass slide. Specimens representing 17 distinct kinds of pediatric solid tumors will be used in this study. Also included will be samples of plexiform neurofibroma-that is, benign growths of nervous and connective tissues. Tissue specimens will come from patients who were age 25 or younger at the time of diagnosis of their cancer or plexiform neurofibroma. No procedures will be performed for the sole purpose of obtaining tissue for this study. The TMA developed in this study will not be commercialized. The results for individuals whose tumor specimens are used in the array will not be sent to patients or their treating physicians.
This phase II trial is studying how well AZD2171 works in treating patients with neurofibromatosis type 1 and plexiform neurofibroma and/or neurofibroma near the spine. AZD2171 may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth and by blocking blood flow to the tumor.
RATIONALE: PEG-interferon alfa-2b may interfere with the growth of tumor cells. PURPOSE: This phase I trial is studying the side effects and best dose of PEG-interferon alfa-2b in treating young patients with plexiform neurofibroma.
Background: Neurofibromatosis Type 1 (NF1) is an autosomal dominant, progressive genetic disorder characterized by diverse clinical manifestations. Patients with NF1 have an increased risk of developing tumors of the central and peripheral nervous system including plexiform neurofibromas, which are benign nerve sheath tumors that may cause severe morbidity and possible mortality. The histopathology of these tumors suggests that events connected with formation of fibroblasts might constitute a point of molecular vulnerability. Gene profile analysis demonstrates overexpression of fibroblast growth factor, epidermal growth factor, and platelet-derived growth factor in plexiform neurofibromas in patients with NF1. Pirfenidone is a novel antifibrotic agent that inhibits these and other growth factors. Clinical experience in adults has demonstrated that pirfenidone is effective in a variety of fibrosing conditions and pirfenidone is presently under study in a phase II trial for adults with progressive plexiform neurofibromas. A phase I trial of pirfenidone in children and young adults with NF1 and plexiform neurofibromas was completed, and has established the phase II dose (the dose resulting in a mean drug exposure \[AUC\] not more than 1 standard deviation below the mean drug exposure \[AUC\] in adults who received pirfenidone at the dose level demonstrating activity in fibrosing conditions). Pirfenidone has been well tolerated. Objectives: To determine whether pirfenidone increases the time to disease progression based on volumetric measurements in children and young adults with NF1 and growing plexiform neurofibromas. To define the objective response rate to pirfenidone in NF1-related plexiform neurofibromas. To describe and define the toxicities of pirfenidone. Eligibility: Individuals (greater than or equal to 3 years to less than or equal to 21 years of age) with a clinical diagnosis of NF1 and inoperable, measurable, and progressive plexiform neurofibromas that have the potential to cause substantial morbidity. Design: The phase II dose will be used in a single stage, single arm phase II trial The natural history of the growth of plexiform neurofibromas is unknown. For this reason, time to disease progression on the placebo arm of an ongoing National Cancer Institute (NCI) Pediatric Oncology Branch (POB) placebo-controlled, double-blind, cross-over phase II trial of the farnesyltransferase inhibitor R115777 for children and young adults with NF1 and progressive plexiform neurofibromas. Funding source - Food and Drug Administration (FDA) Office of Orphan Products Development (OOPD)
RATIONALE: New imaging procedures such as fludeoxyglucose F 18 positron emission tomography (FDG-PET) and magnetic resonance (MR) perfusion imaging may improve the ability to detect disease progression, help doctors predict a patient's response to treatment, and help plan the most effective treatment. PURPOSE: This diagnostic trial is studying how well FDG-PET and MR perfusion imaging work in finding disease progression and determining response to treatment in patients with neurofibromatosis 1 and plexiform neurofibroma.
RATIONALE: Chemoprevention therapy is the use of certain drugs to try to prevent the development or recurrence of cancer. Pirfenidone may slow the growth or prevent further development of plexiform neurofibromas. PURPOSE: Phase I trial to study the effectiveness of pirfenidone in treating young patients who have neurofibromatosis type 1 and plexiform neurofibroma.
RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining methotrexate with vinblastine may be effective treatment for neurofibromatosis type 1 associated with progressive plexiform neurofibromas. PURPOSE: Phase II trial to study the effectiveness of combination chemotherapy in treating patients who have neurofibromatosis type 1 associated with progressive plexiform neurofibromas.
This study will examine whether the experimental drug R115777 (Tipifarnib) can shrink or slow the growth of plexiform neurofibromas in children and young adults with neurofibromatosis type 1 (NF1) and determine what side effects are related to treatment. Plexiform tumors arise from nerves; the only effective treatment is surgical removal. Often, however, not all the tumors can be removed, because of their number or location. Patients with NF1 have a reduced amount of the protein neurofibromin. Neurofibromin is thought to help control the activity of another protein, called ras, which regulates cell growth. Too little neurofibromin, therefore, may allow for uncontrolled cell growth and tumor formation. R115777 interferes with the function of the ras and other proteins. In test tube and animal studies, R115777 has blocked the growth of cancer cells. This study will examine whether the drug is effective against plexiform tumors. Patients with NF1 and progressive plexiform neurofibromas between 3 and 25 years of age may be eligible for this study. Patients whose tumors can be successfully removed surgically may not participate in this study. Candidates are screened with a medical history and physical and eye examinations, blood and urine tests, and magnetic resonance imaging (MRI). Photographs are taken of tumors visible on the body surface. Study participants are randomly assigned to receive either R115777 or placebo (an inactive substance). They take R115777 or placebo tablets every 12 hours for 21 days, followed by a 7-day rest period. This constitutes one 28-day treatment cycle. Treatment continues for as long as the tumors remain stable or shrink and side effects are tolerable. The treatment is switched (for example, from placebo to R115777) or stopped if the tumors grow or if side effects become unacceptable. Patients (or their parents) keep a record of side effects. For the first 3 treatment cycles, patients have a physical examination and blood tests every other week. Blood tests are also done before starting treatment, and at one time point after at least 14 days of treatment to measure the effect of R115777 on proteins in blood cells. A blood sample is obtained before starting treatment and before cycles 4, 7 and 10 and then after every 6 cycles to measure the level of a substance called nerve growth factor. The analysis of nerve growth factor is used to determine if it can predict which patients might be at risk of developing side effects from R115777.