1. Diagnosis of congenital or acquired primary autoimmune and idiopathic chronic neutropenic disorder greater than or equal to 6 months prior to the screening visit that is not attributable to medications, active or recent infections or malignancy.
2. Congenital Neutropenia, including but not limited to these classifications:

a. Isolated with a permanent (non-cyclic) presentation, for example, elastase, neutrophil expressed (ELANE), colony stimulating factor 3 receptor (CSF3R), C-X-C chemokine receptor 2 (CXCR2), Wiskott-Aldrich syndrome (WAS)

b. Associated with extra-hematologic manifestations, for example, Barth syndrome, Cohen syndrome, glucose-6-phosphatase catalytic subunit 3 (G6PC3), Kostmann disease

c. Associated with metabolic disorders, for example, glycogen storage disease 1b (GSD1b)

d. Shwachman-Diamond syndrome

1. Acquired Primary Neutropenia

a. Chronic idiopathic neutropenia

b. Primary autoimmune neutropenia. Other chronic neutropenia (CN) disorders that may be eligible for enrollment can be clarified and approved upon discussion with study Medical Monitor and Sponsor.

1. Have an ANC less than 1000 cells/µL during screening (single ANC value from hematology) and confirmed trough mean ANC (mean value of multiple ANC measurements over 6 hours) at baseline visit, with no clinical evidence of systemic infection.
2. Prior history of recurrent and/or serious infections during the 12 months preceding the screening visit (that is, suffering sequelae of chronic neutropenia), as defined by having at least 2 infections in the last 12 months that meet the following criteria:
3. Infection requiring the use of antibiotics (intravenous [IV]/oral); OR
4. Infection requiring a visit to healthcare facility (including but not limited to emergency room visit, urgent care facility, primary care physician's office, or in-patient hospitalization);

AND for all potential participants:

1. Infections considered by the Investigator to be likely related to the potential participant's CN disorder.
2. Participants who are on G-CSF or other active background therapy must have been receiving these therapies during the previous 12 months while continuing to suffer from infections, be on a stable dose and dosing schedule for ≥4 weeks prior to screening visit and remain on this dose and dosing schedule throughout the study (unless ANC greater than 10,000 cells/µL for greater than or equal to 4 weeks).
3. Participants must be willing to keep their G-CSF or other background therapy doses/regimens stable (other than for safety reasons) for the duration of the study.

Key

A diagnosis of secondary neutropenia including those due to:

1. Hypersplenism
2. Infection
3. Malignancy
4. Autoimmune disease, for example, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, graft-versus-host disease, thyroid disease
5. Nutritional deficiency, for example, vitamin B12, folic acid, copper, caloric malnutrition
6. Drug-induced cause, for example, chemotherapy, clozapine, antiretrovirals, antibiotics, monoclonal antibodies.

A diagnosis of any of the following:

1. Aplastic anemia
2. Warts, hypogammaglobulinemia, infections, and myelokathexis (WHIM) syndrome
3. Certain CNs, including but not limited to these classifications are excluded:

Note: Other protocol-defined inclusion and exclusion criteria apply.