Safety and Activity of SNX-5422 Plus Ibrutinib in CLL

Inclusion Criteria:

* Males or non-pregnant, non-breastfeeding females 18 years-of-age or older
* A diagnosis of CLL as defined by IWCLL 2008 criteria and currently on treatment with ibrutinib without evidence of disease progression.
* No more than 4 prior lines of anti leukemia therapy (not including ibrutinib)
* Presence of mutated BTK in ≥ 4% of peripheral blood or bone marrow CLL cells, or ≥1% and rising on two separate measurements obtained at least 28 days apart.
* Life expectancy of at least 9 months
* Karnofsky performance score 70
* Adequate baseline laboratory assessments
* Signed informed consent form
* Recovered from toxicities of previous anticancer therapy to CTCAE Grade ≤ 1 with the exception of alopecia
* Subjects with reproductive capability must agree to practice adequate contraception methods.

Exclusion Criteria:

* Subjects experiencing toxicity with ibrutinib
* Prior treatment with any Hsp90 inhibitor.
* Major surgery or significant traumatic injury within 4 weeks of starting study treatment.
* Conventional chemotherapy or radiation within 4 weeks.
* The need for treatment with medications with clinically-relevant metabolism by the cytochrome P450 (CYP) 3A4 isoenzyme within 3 hours before or after administration of SNX-5422
* Screening ECG QTc interval 470 msec for females, 450 msec for males.
* At increased risk for developing prolonged QT interval unless corrected to within normal limits prior to first dose of SNX-5422
* Patients with chronic diarrhea or with Grade 2 or greater diarrhea despite appropriate medical management.
* Gastrointestinal diseases or conditions that could affect drug absorption
* Gastrointestinal diseases that could alter the assessment of safety, including irritable bowel syndrome, ulcerative colitis, Crohn's disease, or hemorrhagic coloproctitis.
* History of documented adrenal dysfunction not due to malignancy.
* History of chronic liver disease.
* Active hepatitis A or B.
* Current alcohol dependence or drug abuse.
* Use of an investigational treatment (except for ibrutinib) from 30 days prior to the first dose
* Glaucoma, retinitis pigmentosa, macular degeneration, or any retinal changes detected by ophthalmological examination that are considered clinically important by examiner.
* Psychological or social reasons that would hinder or prevent compliance with the requirements of the protocol or compromise the informed consent process.