Clinical trial of "line extension" of drug ARAFARMADOL® 0.075% cream in a new formulation in topical solution applicable in roll-on and with the same therapeutic indications approved for the cream.

The sponsor created a new pharmaceutical formulation of CAPSAICIN topical solution applicable in roll-on. This new formulation in roll-on represents a line extension of drug ARAFARMADOL 0.075 cream, which is currently marketed in Spain by the sponsor.

The proposed investigational product as topical solution applicable in roll-on is expected to solve the compliance and safety issues of the cream with the same indications for use.

Eligible patients will be randomized into two groups: CAPSAICIN topical solution applicable in roll-on and CAPSAICIN cream (ARAFARMADOL® ) for 8 weeks. Then, they will have a 4 week washout period and will be crossed over to the other treatment group for 8 weeks. A follow-up period of 2 weeks will take place after the end of both treatments.

Inclusion Criteria:

1. Written or oral informed consent with witnesses, before initiating the specific procedures of the protocol.
2. Non-pregnant, non-lactating man or woman ≥ 18 years.
3. Patients diagnosed with Type I or II Diabetes Mellitus, treated or untreated.
4. Patients with a diagnosis of painful peripheral diabetic neuropathy, treated or not treated
5. Painful diabetic neuropathy of at least 3 months of evolution with moderate to severe pain ≥ 4 on the VAS scale in the selection phase.
6. The pain must have been experienced daily, interfered with daily activities or sleep, and not attributable to psychological origin.
7. Stabilization of pain medication at least during the month prior to the start of treatment. The patient must be prepared to remain in treatment with the same pain medications at the same doses as previous to the start, during the study and in the follow-up phase (24 weeks).
8. Intact, non-irritated and dry skin in the painful areas to be treated.
9. Patients with the ability to collaborate in the trial.

Exclusion Criteria:

1. Allergic reactions to capsaicin.

2. Patients with neuropathic pain of an etiology other than diabetes.

3. Patients with peripheral ischemic pain due to diabetic artery disease.

4. Patients with unstable glycemic control (glycosylated Hb ≥ 10.5%).

5. Amputation of any part of the lower limb.

6. Surgery scheduled during the clinical trial.

7. Mild painful diabetic neuropathy (<4 VAS).

8. Other serious pathologies:

   • Documented congestive heart failure or systolic dysfunction (LVEF ≤ 50%).
   • Previous history of myocardial infarction in the 6 months prior to enrollment.
   • Uncontrolled hypertension (160/110 mmHg maximum).
   • Uncontrolled high-risk arrhythmias.
   • Significant neurological or psychiatric disorders, including psychotic disorders, dementia that prevent patients from understanding and giving informed consent.
   • Active uncontrolled infection.

9. Use other topical pain medications in painful areas.

10. History or current problem of substance abuse.

11. Pregnant or lactating women. Women of childbearing potential should use effective contraception.

12. Participation in another clinical trial with any non-marketed investigational drug during the 90 days prior to inclusion.