Harvoni Treatment Porphyria Cutanea Tarda

Inclusion Criteria 1. Willing and able to give informed consent 2. ≥18 years of age 3. Symptoms and signs consistent with PCT and well documented biochemical diagnosis (urinary total porphyrin excretion \> 500 mcg/g Creatinine with HPLC pattern typical of PCT-predominance of 8- and 7-carboxyl porphyrins) 4. Clinical diagnosis of PCT established by a study PI 5. Chronic hepatitis C: HCV RNA positive and quantifiable in serum detected within 90 days of enrollment, and documented HCV genotypes 1,4, 5, or 6 for which Harvoni is an approved therapy. 6. Women of child-bearing potential must be willing to avoid pregnancy and use an accepted and effective contraceptive method during treatment. Exclusion Criteria 1. Women who are pregnant or who are breast-feeding 2. Patients who have already started treatment of PCT with phlebotomy or low dose hydroxychloroquine or chloroquine, or who have been in such treatment in the past 30 days 3. Patients who have already started another treatment regimen for CHC, or who have taken such treatment in the past 30 days 4. HIV infection with CD4 counts at baseline less than 350/µL or with evidence of any active AIDS-defining illnesses 5. Ongoing active alcohol abuse, defined as a history of drinking more than 25 drinks of alcohol per week during most weeks in the prior 4 months (History of prior, but not current alcohol abuse will NOT be grounds for exclusion because we seek to treat subjects with PCT and CHC of the type typically seen in clinical practice) 6. Any ongoing active IV drug use 7. Patients who are taking amiodarone or who have taken amiodarone within 60 days prior to enrollment 8. Patients who are taking, or within the prior 28 days have taken, rifampicin or St John's wort (Hypericum perforatum), both of which are P-gp inducers, which may significantly reduce the drug levels and therapeutic effects of Harvoni 9. Uncontrolled diabetes (Hgb A1c \>9.5% within 60 days prior to enrollment) 10. Chronic hepatitis B 11. Autoimmune hepatic liver injury-autoimmune hepatitis, primary biliary cholangitis/sclerosing cholangitis or overlap syndrome 12. Alcoholic hepatitis 13. Other metabolic disorders of the liver, e.g. Alpha 1 antitrypsin deficiency with ZZ Pi type, Wilson's disease 14. Prior known or suspected drug-induced liver injury within 6 months of enrollment 15. Known or suspected hepatocellular carcinoma 16. On liver transplant list, or current MELD \>12 17. History of liver transplant 18. Estimated GFR (Creatinine clearance) \<30 mL/min (per Sofosbuvir being cleared by the kidney) 19. Serum ALT or AST \>10x normal 20. Serum bilirubin \>2 mg/dL (excluding patients with known or suspected Gilbert's syndrome) 21. Any other comorbid condition, which, in the opinion of the investigator, precludes participation