Patients with recurrent, refractory or metastatic solid tumors have a dismal prognosis with few viable treatment options. Hydroxychloroquine (HCQ) is an agent that has been widely used to treat malaria. Because HCQ also inhibits autophagy, a process central to survival of cancer in the face of metabolic stress, including the effects of anti-cancer therapy, it is now in human cancer trials combined with other agents to attempt to boost the efficacy of those agents. Autophagy inhibition improves the activity of sorafenib in hepatocellular carcinoma.

Sorafenib is an oral multi-kinase inhibitor that blocks not only receptor tyrosine kinases such as KIT, VEGFR and PDGFR but also serine/threonine kinases along the RAS/RAF/MEK/ERK pathway.

The investigators propose to treat patients with refractory or relapsed solid tumors with sorafenib, to boost its efficacy while attempting to mitigate its toxicity by combining with HCQ.

Inclusion Criteria:

• Able to provide informed consent
• Not on immune-modulating drugs, except those used as study drug premedication, unless the principal investigator grants an exception (which exception must be documented in writing)
• Patients with relapsed or refractory solid tumors with no viable treatment options
• Measurable disease within 30 days of study enrollment
• Blood hemoglobin > 8.5 gm/dl within 7 days of study enrollment
• Absolute neutrophil count > 1000/mm3 within 7 days of study enrollment
• Platelet count > 50,000/mm3 within 7 days of study enrollment
• SGOT <10x upper limit of normal within 7 days of study enrollment
• No chemotherapy or radiation therapy in the 14 days prior to initiation of treatment on this study. No other concurrent chemotherapy, surgery or radiation therapy during this protocol except surgery or radiation therapy to control symptoms with concurrence of the principal investigator.
• No contraindication to any study treatment
• No active major medical problems, including untreated or uncontrolled infections
• If of reproductive potential, a negative urine or blood pregnancy test within 3 days of study enrollment, and agreement to use adequate contraception. In relevant subjects, pregnancy testing will continue monthly while on treatment unless the subject is no longer able to become pregnant or there is sufficient justification otherwise
• Not breast feeding
• Life expectancy > 6 months
• ECOG performance status < 2
• Age 18+ years
• No active substance abuse in the prior 6 months
• Not on digoxin or cimetidine

Exclusion Criteria:

• Contraindication or hypersensitivity to any study drug or its components or excipients
• Current pregnancy or breast feeding
• Inability to document adequate contraception if a female of reproductive potential
• Chemotherapy or radiation therapy within the 14 days prior to initiation of study treatment
• Prior treatment with sorafenib. Prior HCQ use is not an exclusion.
• Life expectancy < 6 months
• ECOG performance status > 2
• Symptomatic coronary artery disease (including uncontrolled angina, congestive heart failure, and the like)
• Uncontrolled hypertension (diastolic BP consistently >100 mm Hg or systolic BP consistently >160 mm Hg on a regular basis)
• Uncontrolled, symptomatic cardiac arrhythmia
• Active substance abuse in the prior 6 months