Study was terminated due to sponsor decision. This decision was not related to safety concerns with REC-2282.

This is a two-staged, Phase 2/3, randomized, multi-center study to investigate the efficacy and safety of REC-2282 in participants with progressive NF2 mutated meningiomas.

Cohort A (Phase 2) will provide early data on efficacy and safety of REC-2282 in participants with progressive NF2 mutated meningiomas, and provide guidance for the dose in the confirmatory part of the study (Cohort B, Phase 3). The purpose of Cohort B of the study is to assess the efficacy and safety of REC-2282 compared with placebo in participants with progressive NF2 mutated meningiomas.

In both cohorts, there will be a screening period of up to 8 weeks, a treatment period, a 4-week safety follow-up period after the end of treatment, and a 6-month post-study follow-up. The first 8 participants enrolled in Cohort A will complete a food effect run-in sub study. At the end of the study period, participants may be offered participation in an open-label extension (OLE) period.

In Cohort A, adult participants will be randomized to one of two dose levels of REC-2282.

In Cohort B, participants will be randomized to REC-2282 treatment (dose to be determined from Cohort A) arm or placebo arm in a ratio of 2:1.

Inclusion Criteria:

1. ≥12 years of age and weighing at least 40 kg
2. Progressive meningioma that is amenable to volumetric analysis
3. Has either 1) sporadic meningioma with confirmed NF2 mutation; or, 2) confirmed diagnosis of NF2 disease (revised Manchester criteria); or, 3) at least one NF2-related tumor (with pathogenic germline or proven mosaic NF2 variant)
4. Adequate bone marrow function
5. Has provided written informed consent/assent to participate in the study

Exclusion Criteria:

1. Progressive disease associated with significant or disabling clinical symptoms likely to require surgery or radiation therapy within the next 3 months.
2. Received prior surgery, radiosurgery, or laser interstitial thermal therapy in the target tumor, or immediately adjacent to the target tumor within 12 months prior to screening.
3. Received an anti- tumor agent for meningioma within 3 months, or 5 half-lives (whichever is longer), prior to screening.
4. History of an active malignancy within the previous 3 years except for localized cancers that are considered cured, and, in the opinion of the investigator, present a low risk of recurrence.
5. Received another investigational drug within 30 days prior to screening
6. Pregnant, lactating, or is planning to attempt to become pregnant or impregnate someone during this study or within 90 days after the last dosing cycle.

Masking applies to Cohort B only.