Treatment Preference for Weekly Dipeptidyl Peptidase-4 (DPP-4) Inhibitors Versus Daily DPP-4 Inhibitors in Participants With Type 2 Diabetes Mellitus

The purpose of this study is to examine the participant's preference for treatment with once-weekly dosing of DPP-4 inhibitor trelagliptin versus once-daily dosing of DPP-4 inhibitor alogliptin among the participants with type 2 diabetes mellitus who are being treated with once-daily dosing of DPP-4 inhibitor.

The drugs being tested in this study are called Trelagliptin and Alogliptin. This study will look at the participant's preference for treatment with Trelagliptin versus Alogliptin.

The study enrolled 60 patients. Participants will be randomly assigned (by chance, like flipping a coin) to one of the two treatment groups:

* Trelagliptin 100 mg, followed by Alogliptin 25 mg
* Alogliptin 25 mg, followed by Trelagliptin 100 mg All participants will be asked to take one tablet of trelagliptin orally once a week or one tablet of alogliptin orally once a day throughout the study period.

This multi-center trial will be conducted in Japan. The overall time to participate in this study is 16 weeks. Participants will make 3 visits to the clinic.

Eligibility Criteria:
Inclusion Criteria:

1. Participants who have been diagnosed with type 2 diabetes mellitus.
2. Participants who are being treated with any of the following DPP-4 inhibitors for at least 8 weeks prior to the time of informed consent (Week 0).

   * Sitagliptin : 50 mg once daily
   * Alogliptin : 25 mg once daily
   * Linagliptin : 5 mg once daily
   * Teneligliptin : 20 mg once daily
   * Saxagliptin : 5 mg once daily
3. Participants who were judged by the investigators possible to change the treatment from daily dosing of DPP-4 inhibitor shown in Inclusion Criteria 2 to study drug trelagliptin 100 mg or alogliptin 25 mg.
4. Participants whose glycosylated hemoglobin (HbA1c) value measured within 8 weeks prior to the time of informed consent (Week 0) is below 10.0%.
5. Participants who responded to Diabetes Treatment Satisfaction Questionnaire (DTSQ) at the time of informed consent (Week 0).
6. Participants who were judged by the investigators capable to understand the contents of this clinical research and comply with them.
7. Participants who are able to sign and date the Informed Consent Form before any clinical research procedure begins.
8. Participants who are at least 20 years old at the time of giving the consent.
9. Participants who are classified as outpatients.

Exclusion Criteria:

1. Participants who have a history of taking once-weekly dosing of DPP-4 inhibitor (trelagliptin or omarigliptin).
2. Participants who are being treated with drugs other than those for once-daily oral dosing for the purpose of treatment of chronic complication (for example, "BENET® Tablets 75 mg", a therapeutic agent for osteoporosis which is administered once monthly).
3. Participants who are being treated with twice-daily dosing of DPP-4 inhibitor (vildagliptin or anagliptin).
4. Participants who are being treated with anti-diabetic fixed-dose combination pill contained a DPP-4 inhibitor.
5. Participants with moderate or severe renal impairment (for example, participant whose estimated glomerular filtration rate (eGFR) is below 60 mL/min/1.73m\^2).
6. Participants for whom blood sugar control by insulin preparations is desired (for example, participants with severe ketosis, diabetic coma or precoma, type 1 diabetes mellitus, severe infection, or serious trauma before or after surgery).
7. Participants who have a history of hypersensitivity or allergy to DPP-4 inhibitor.
8. Participants with serious heart disease, cerebrovascular disorder, or participants with serious disease in the pancreas, blood, etc.
9. Participants with unstable proliferative diabetic retinopathy.
10. Participants with malignant tumor.
11. Participants who are pregnant, breast-feeding, possibly pregnant, or planning to become pregnant.
12. Participants participating in other clinical studies.
13. Participants who have been determined as inappropriate participants by the investigator.