The purpose of this study is to determine whether AGuIX (Activation and Guidance of Irradiation by X-ray) gadolinium-based nanoparticles make radiation work more effectively in the treatment of patients with brain metastases that are more difficult to control with stereotactic radiation alone.

This research study is a double-blind, randomized phase II clinical trial of brain-directed stereotactic radiation with or without AGuIX (Activation and Guidance of Irradiation by X-ray) gadolinium-based nanoparticles in the management of brain metastases at higher-risk of local recurrence with radiation alone.

The study agent (AGuIX gadolinium-based nanoparticles) has two main parts. The first is gadolinium, also known as "contrast," which is typically injected into a vein during a MRI scan. The second part is a nanoparticle (linked to the gadolinium) that may make focused radiation work more effectively. The AGuIX gadolinium-based nanoparticles are deposited within the brain metastases via the bloodstream and then the brain metastases are radiated.

The U.S. Food and Drug Administration (FDA) has not approved AGuIX gadolinium-based nanoparticles as a treatment for any disease. AGuIX gadolinium-based nanoparticles have been tested in other studies for safety and efficacy in patients with brain metastases who are also receiving radiation.

This study seeks to determine whether AGuIX gadolinium-based nanoparticles improve outcomes relative to placebo.Participants will be "randomized" into one of the study groups:

• Group A: Radiation plus AGuIX gadolinium-based nanoparticles
• Group B: Radiation plus placebo

The research study procedures include screening for eligibility and study treatment including evaluations and follow up visits.

TherAguix, the manufacturer of the AGuIX gadolinium-based nanoparticles, is supporting this research study by providing the AGuIX gadolinium-based nanoparticles that will be evaluated in this study.

TherAguix is also covering the cost of the study.

It is expected that about 134 people will take part in this research study.

Inclusion Criteria:

• Participants must have a biopsy proven solid malignancy and at least one intracranial measurable lesion spanning ≥5mm in maximal unidimensional size and radiographically consistent with or pathologically proven to be a brain metastasis AND meet one of the following additional criteria regarding the primary site or nature of the intracranial disease:

  • Melanoma with intracranial growth consistent with tumor progression despite immunotherapy
  • Gastrointestinal primary
  • HER2 positive breast cancer (subtype assessed using most representative tissue available in opinion of enrolling clinician and/or study PI)
  • Cystic metastases
  • Metastases ≥2cm in maximal unidimensional size
  • Locally recurrent metastases after prior stereotactic radiation
  • Locally recurrent metastases after prior whole brain radiation *Patients with metastases from melanoma, GI primaries, or HER2+ breast cancer, as well as those with cystic metastases or metastases ≥2cm in maximal unidimensional size, who have local recurrences after prior brain-directed radiation can only be treated in the strata permitting prior radiation (last two strata above)

• Age ≥18 years at diagnosis of brain metastases

• Estimated glomerular filtration rate of ≥ 60 mL/min/1.73m2

• Karnofsky performance status of at least 70 (i.e. at minimum, "cares for self" but "unable to carry on normal activity or do active work")

• Estimated survival based on extracranial disease of at least 3 months in the opinion of the enrolling clinician and/or study PI

• Ability to understand and the willingness to sign a written informed consent document

• The effects of AGuIX on the developing human fetus are unknown. For this reason, women of child-bearing potential must agree to use adequate contraception prior to study entry and for the duration of the therapeutic component of study participation

Exclusion Criteria:

• Participants who cannot undergo a brain MRI
• Participants who cannot receive gadolinium
• Participants with widespread, definitive leptomeningeal disease
• Patients requiring radiation to either >10 targets (if naïve to whole brain radiation) or >20 targets (if whole brain radiation has been given previously) per the discretion of the treating clinician and/or study PI
• Pregnant women are excluded from this study because of the potential deleterious effects of gadolinium on the developing fetus. Because there is an unknown but potential risk for adverse events in nursing infants, women who are breastfeeding are not eligible for this study
• In cohorts who have received prior brain-directed radiation, patients are not eligible for this study if they have active (at the time of protocol screening) brain metastases that require radiation that are in or within 1.0cm of the brainstem, eyes, optic nerves, or optic chiasm if the juxtaposed organ at risk (i.e. brainstem, eyes, optic nerves, or optic chiasm) has previously received either >6.0 Gy in a single fraction or, if prior radiation was fractionated, a cumulative dose in 2.0 Gy equivalents, using an alpha/beta ratio of 2, of >40.0 Gy. In addition, all patients who have had prior brain-directed radiation, regardless of technique/dose/fractionation, are not eligible for the study until written approval is provided by the study/site PI

The Dana-Farber / Harvard Cancer Center encourages and supports the responsible and ethical sharing of data from clinical trials. De-identified participant data from the final research dataset used in the published manuscript may only be shared under the terms of a Data Use Agreement. Requests may be directed to: [contact information for Sponsor Investigator or designee]. The protocol and statistical analysis plan will be made available on Clinicaltrials.gov only as required by federal regulation or as a condition of awards and agreements supporting the research.

Data can be shared no earlier than 1 year following the date of publication

Contact the Belfer Office for Dana-Farber Innovations (BODFI) at innovation@dfci.harvard.edu