Subjects did not receive Hope Pharmaceuticals' Sodium Thiosulfate Injection.

This is an 8-week observational follow-up study of patients who participated in the ST-001 CALISTA study (A Phase 3, Intravenous Sodium Thiosulfate for Acute Calciphylaxis Treatment: A Multicenter, Randomized, Double-blind, Placebo-controlled Clinical Trial).

This is an 8-week observational follow-up study of patients who participated in the ST-001 CALISTA study. In this ST-003 (OF-CALISTA) study, the occurrence of delayed adverse events, standard of care treatments for calciphylaxis (medications [including Sodium Thiosulfate Injection and pain medication], wound debridement, amputation, hyperbaric oxygen therapy, and surgical parathyroidectomy), and calciphylaxis-related complications (new or worsening skin lesions, ulceration, infection, sepsis and hospitalizations) will be recorded during an 8-week observation period following patient participation in the ST-001 CALISTA study (A Phase 3, Intravenous Sodium Thiosulfate for Acute Calciphylaxis Treatment: A Multicenter, Randomized, Double-blind, Placebo-controlled Clinical Trial).

Inclusion Criteria:

• Previously enrolled as a patient in ST-001 CALISTA study
• Willing to provide written informed consent
• Willing and able to adhere to all study-related procedures
• Willing to authorize release of medical records
• Willing to authorize collection of medical data from health care providers
• Provide email, home address and phone number where he/she can be reached

Exclusion Criteria:

• Patient did not participate in ST-001 CALISTA study

Those calciphylaxis patients that previously participated in the ST-001 CALISTA study (A Phase 3, Intravenous Sodium Thiosulfate for Acute Calciphylaxis Treatment: A Multicenter, Randomized, Double-blind, Placebo-controlled Clinical Trial).