Inclusion Criteria:

          -  Histologically or cytologically confirmed metastatic or unresectable locally advanced
             NSCLC with known sensitive EGFR mutations. Patients with mutations in T790M are
             eligible if they have progressed after treatment with a third generation EGFR tyrosine
             kinase inhibitor (osimertinib), but otherwise patients must have EGFR T790M negative
             or unknown status. Patients previously treated with third generation EGFR tyrosine
             kinase inhibitor must have achieved a treatment benefit of at least 4 months.

          -  Disease progression following therapy with erlotinib, afatinib, or gefitinib

          -  May have received one or more prior treatments with chemotherapy

          -  Measurable disease defined as lesions that can be accurately measured in at least one
             dimension (longest diameter to be recorded) as ≥ 10 mm with CT scan, as ≥ 20 mm by
             chest x-ray, or ≥ 10 mm with calipers by clinical exam.

          -  At least 18 years of age.

          -  ECOG performance status ≤ 1

          -  Normal bone marrow and organ function as defined below:

               -  Absolute neutrophil count ≥ 1,500/mcl

               -  Platelets ≥ 100,000/mcl

               -  Hemoglobin ≥ 9.0 g/dL

               -  Total bilirubin ≤ 2.0 x IULN

               -  AST (SGOT) / ALT (SGPT) ≤ 3.0 x IULN; if liver metastases, ≤ 5.0 x IULN

               -  Serum creatinine ≤ 1.5 x ULN

          -  Adequate cardiac function as demonstrated by LVEF ≥ 50% performed no more than 4 weeks
             prior to enrollment.

          -  Women of childbearing potential and men must agree to use adequate contraception
             (hormonal or barrier method of birth control, abstinence) prior to study entry and for
             the duration of study participation. Should a woman become pregnant or suspect she is
             pregnant while participating in this study, she must inform her treating physician
             immediately.

          -  Able to swallow pills

          -  Able to understand and willing to sign a Human Research Protection Office (HRPO)
             approved written informed consent document (or that of legally authorized
             representative, if applicable).

        Exclusion Criteria:

          -  Known pre-existing interstitial lung disease.

          -  Leptomeningeal carcinomatosis or other untreated or symptomatic central nervous system
             (CNS) metastases. Patients with asymptomatic CNS metastases, other than leptomeningeal
             disease, are eligible provided they have been clinically stable without requiring
             increase in steroid dose for at least 4 weeks.

          -  A history of other malignancy ≤ 5 years previous with the exception of basal cell or
             squamous cell carcinoma of the skin which were treated with local resection only or
             carcinoma in situ of the cervix.

          -  Received any chemotherapeutic or targeted agent (approved or investigational) for
             NSCLC within 2 weeks of initiation of pacritinib (with the exception of erlotinib).

          -  Currently receiving any other investigational agents.

          -  A history of allergic reactions attributed to compounds of similar chemical or
             biologic composition to pacritinib or other agents used in the study.

          -  Uncontrolled intercurrent illness including, but not limited to, ongoing or active
             infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
             arrhythmia, or psychiatric illness/social situations that would limit compliance with
             study requirements.

          -  Pregnant and/or breastfeeding: Patient must have a negative pregnancy test within 14
             days of study entry.

          -  Known HIV-positivity on combination antiretroviral therapy because of the potential
             for pharmacokinetic interactions with pacritinib. In addition, these patients are at
             increased risk of lethal infections when treated with marrow-suppressive therapy.
             Appropriate studies will be undertaken in patients receiving combination
             antiretroviral therapy when indicated.

          -  Use of potent cytochrome P450 3A4 (CYP3A4) inducer within one week of pacritinib
             initiation

          -  Patients with CTCAE grade 2 cardiac arrhythmias may be considered for inclusion if the
             arrhythmias are stable, asymptomatic, and unlikely to affect patient safety. Patients
             will be excluded if they have ongoing cardiac dysrhythmias of CTCAE grade ≥ 3,
             corrected QT interval (QTc) prolongation >450ms, or other factors that increase the
             risk for QT interval prolongation (eg, heart failure, hypokalemia [defined as serum
             potassium <3.0mEq/L that is persistent and refractory to correction], or family
             history of long QT interval syndrome).

          -  Any gastrointestinal (GI) or metabolic condition that could interfere with absorption
             of oral medication such as ongoing grade 3 or higher diarrhea, constipation, nausea,
             or vomiting.

          -  Active viral hepatitis.