LUM-201-10

Inclusion Criteria:
*  Subjects must be naïve to treatment and prepubertal
*  Subjects must have a maximal GH response of \< 10 ng/mL from 2 prior GH stimulation tests conducted within the preceding 12 months
*  Impaired height defined as ≥ 2.0 standard deviations (SDs) below the mean height for chronological age and sex
*  Morning or random cortisol level of ≥ 7.0 μg/dL
*  ≥ 3.0 years and age ≤ 10.0 years for girls and ≤ 11.0 years for boys
*  Baseline height velocity (HV) based on ≥ 6 months of growth assessments \< 25th percentile for age and sex
*  Bone Age delay of ≥ 12 months compared to the chronological age
*  In girls, have genetic testing results to rule out Turner syndrome. If SHOX genetic testing results are available, they need to be negative.
*  Have normal thyroid function. Subjects diagnosed with hypothyroidism must have documented successful treatment for at least 3 months prior to Day 1
*  Baseline IGF-1 standard deviation score (SDS) ≤ -1.0

Exclusion Criteria:
*  Any medical or genetic condition which, in the opinion of the Investigator or Medical Monitor (MM), can be an independent cause of short stature and/or limit the response to exogenous growth factor treatment.
*  Arm span to height ratio \> 2 SDs below the mean for age and sex
*  A medical or genetic condition that, in the opinion of the Investigator and/or MM, adds unwarranted risk to use of LUM-201
*  Use of any medication that, in the opinion of the Investigator and/or MM, can independently cause short stature or limit the response to exogenous growth factors
*  Current inflammatory diseases requiring systemic corticosteroid treatment for \> 2 consecutive weeks within the last 3 months prior to the Screening Visit
*  Use of hormone replacement therapy for any hormone deficiency other than thyroid deficiency
*  Any ECG at the Screening Visit noted to have a clinically significant abnormality, as confirmed by the MM
*  Any subjects suspected of having past or present intracranial tumor growth as confirmed by brain imaging prior to the Screening or Day 1 Visit
*  Any subject suspected of having intracranial hypertension (IH) as confirmed by fundoscopy and other assessments
*  Any subject with serum alanine transaminase (ALT), aspartate transaminase (AST), or total bilirubin \> upper limit of normal (ULN)
*  Suspicion of absent pituitary function as evidenced by a maximal stimulated GH ≤ 3.0 ng/mL on any prior standard of care GH stimulation test completed within 12 months
*  Body weight ≤ 14.0 kg
*  BMI \< -2 or \> +2 SDs for age and sex based on WHO standards
*  Birth weight for gestational age \< 3rd percentile based on WHO standards
*  Treatment with medications known to be moderate or strong inhibitors or strong inducers of cytochrome P450 (CYP) 3A/4
*  History of spinal, cranial, or total body irradiation
*  Attention deficit hyperactivity disorder (ADHD) diagnosis