A Study of Enzyme Replacement Therapy (VPRIV) in People With Type 1 Gaucher Disease Who Were Previously Treated With Substrate Reduction Therapy

The study will provide information on outcomes in people with type 1 Gaucher disease when they are treated with velaglucarase alfa (also called VPRIV), under standard care. Standard care means the participant will be treated according to the clinic's standard practice. The study sponsor will not be involved in how participants are treated with VPRIV, will provide instructions on how the clinic will record what happens during the study.

VPRIV is a type of enzyme replacement therapy (also known as ERT). Before starting the study, participants must either have switched from substrate reduction therapies (SRT) to VPRIV or switched from other enzyme replacement therapies to SRT then finally to VPRIV. During this time, medical data will be collected from the participants' medical records.

During the study, participants will be treated with VPRIV according to their clinic's standard practice. VPRIV is given by a slow injection into the vein, also known as an infusion. This will happen in the clinic or at home.

The study will record if blood levels of specific substances remain stable or improve during the switch to treatment with VPRIV. Some of these substances will show if organs such as the liver or spleen are working well. Others are blood cells that help blood to clot, known as platelets. Another is a substance in a red blood cell used to carry oxygen around the body, known as hemoglobin.

Participants will use a digital tool so they can be more involved in decision making in their treatment. The digital tool is a mobile phone app, in which each participant can log their daily activities, their general health and wellbeing, and other key information.

Medical data will also be collected from the participants' charts during this time.

Health problems of the participants will be recorded during the study to check if there were any side effects from VPRIV treatment.

Participants will be in this study for up to 12 months.


Eligibility Criteria:
Inclusion Criteria:

Participant eligibility is determined according to the following criteria prior to entry into the study:

* In the opinion of the investigator, the participant is capable of understanding and complying with protocol requirements.
* Participant either signs and dates a written, informed consent form or completes an e-consent process prior to the initiation of any study procedures.
* Participant has been diagnosed with GD type I; diagnosis was confirmed biochemically and/or genetically.
* Participant has been treated with SRT for at least 3 months prior to switch to VPRIV.
* Participant has been treated with VPRIV at least 3 months prior to enrollment (Baseline \[Day 0\]).
* Participant is aged 18 or older.
* Arm A: Participant is able to use mobile application based on clinician's judgment, (e.g., owns an iPhone version 5 or later or smartphones with Android operating systems, have an active data plan or regular Wi-Fi access).
* Arm A: The participant's primary language is English.

Exclusion Criteria:

Any participant who meets any of the following criteria will not qualify for entry into the study:

* Participant is an immediate family member, study site employee, or is in a dependent relationship with a study site employee who is involved in conduct of this study (e.g., spouse, parent, child, sibling) or may consent under duress.
* Participant is judged by the investigator as being ineligible for any other reason.
* Participant has L444P/L444P GBA1 genotype (c.1448T greater than \[\>\] C).
* Participant has Parkinson's disease, a history of central nervous system \[CNS\] manifestations, or any other neurological disorder (e.g. Lewy Body Disease, Alzheimer's Disease, Amyotrophic Lateral Sclerosis, Multiple sclerosis).