An Open-Label, Randomized, Multicenter Trial of Encorafenib + Binimetinib Evaluating a Standard-dose and a High-dose Regimen in Patients With BRAFV600-mutant Melanoma Brain Metastasis (POLARIS)

Key Inclusion Criteria:

• Histologically confirmed diagnosis of cutaneous melanoma with metastases to the brain.
• Presence of B-RAF proto-oncogene, V600 mutant (BRAFV600) mutation in tumor tissue previously determined by a local PCR or NGS-based assay at any time prior to Screening or by a central laboratory during Screening.
• Must have at least 1 parenchymal brain lesion ≥ 0.5 cm and ≤ 4 cm, defined as a magnetic resonance imaging (MRI) contrast-enhancing lesion that may be accurately measured in at least 1 dimension. (Measurable intracranial lesions that have been previously irradiated and have not been shown to be progressing following irradiation should not be considered as target lesions).

• Patients may have received the following prior therapies:

  1. Safety Lead-in, Phase 2 Randomized , Phase 2 Arm A Cohort 1: May have received prior local therapy for brain metastases including but not restricted to brain surgery, whole brain radiotherapy, stereotactic radiotherapy or stereotactic radiosurgery. Multiple local (brain) therapies or combinations of local therapies are allowed. For patients receiving local therapy to all brain lesions (including WBRT), progression of pre-existing lesions based on RECIST 1.1 (> 20% increase in longest diameter on baseline scan) or new measurable lesions are required. For patients receiving local therapy for some but not all lesions, disease progression based on RECIST 1.1 is not required as long as there are remaining brain lesions that are measurable and not previously treated.
  2. Phase 2 Arm A Cohort 2: Received no prior local therapy (e.g., brain surgery, craniotomy, SRS or SRT) for brain metastases.
  3. All patients (Safety Lead-In and Phase 2): May have received prior immunotherapy.
  4. All patients (Safety Lead-In and Phase 2): If receiving concomitant corticosteroids must be on a stable or decreasing dose for at least 2 weeks prior to first dose of study treatment (up to a total daily dose of 4mg of dexamethasone or equivalent).
• An Eastern Cooperation Oncology Group Performance Status (ECOG PS) of 0 or 1 and Karnofsky score ≥ 80
• Adequate bone marrow, organ function and laboratory parameters

Key Exclusion Criteria:

• Patients with symptomatic brain metastasis.
• Uveal or mucosal melanoma.
• History of or current leptomeningeal metastases.
• Treatment with SRS or craniotomy within 14 days prior to start of study treatment, or treatment with whole-brain radiation within 28 days prior to study treatment. Patients who received local therapy should have complete recovery with no neurological sequelae.

• Either of the following:

  1. Radiation therapy to non-brain visceral metastasis within 2 weeks prior to start of study treatment;
  2. Continuous or intermittent small-molecule therapeutics or investigational agents within 5 half-lives of the agent (or within 4 weeks prior to start of study treatment, when half-life is unknown).
• Patients treated in the adjuvant setting with BRAF or MEK inhibitor(s) < 6 months prior to enrollment. Patients who received BRAF or MEK inhibitors in the metastatic setting are excluded.
• Patient has not recovered to ≤ Grade 1 from toxic effects of prior therapy before starting study treatment.