Hand and Foot Syndrome (HFS) is a weii-established and frequent cutaneous adverse event of capecitabine used in the treatment of different cancers.HFS is charectirized by a variety of symptoms ranging from mild discomfort to a painful sensation of palms and sols that could limit functionality and hamper patients on their daily activities.

The aim of this study is to explore the TAR-0520 gel safety and preventive efficacy of HFS in patients with colorectal and breast cancer patients treated with capecitabine.

Is the product well tolerated locally and systemically ? Is the product reducing frequency and severity of HFS ? Is product improving Quality of Life (QoL) of treated patients ? Each patient will receive the active TAR-0520 gel and they will apply it to both hands,twice daily. Applications will be done 1 hour before each morning and evening capecitabine oral intake.

Feet will be not treated and will serve as controls. In total , this study will follow patients during 4 capecitabine Cycles (each Cycle=21 days) for a total of 12 weeks.

Clinical evaluations will take place at Day1 of each Cycle and will be conducted separetaly on hands and feet.

Hand-foot syndrome (HFS) is a well-established cutaneous adverse event of certain chemotherapeutic agents mainly capecitabine. HFS is characterized by a wide variety of symptoms ranging from mild discomfort to a painful sensation of palms and soles that could limit functionality and hamper patients on their daily activities. Although not life threatening, it may have a severe impact on quality of life, including incapacity in working or walking, leading possibly to cancer drug discontinuation or dose modification .

The current study aims at exploring the TAR-0520 gel safety and preventative efficacy of HFS in patients with colorectal and breast cancer treated with capecitabine.

This will be an open-label, intra-individual, monocentric, pilot study with approximately 25 patients included.

Patients with histologically confirmed breast cancer or colorectal cancer receiving capecitabine monotherapy with recommended dose (≥ 1000 mg/m² twice daily from day 1 to 14 every 3 weeks) will be enrolled in the trial.

Each patient will receive the active TAR-0520 gel containing 1.5% of Brimonidine tartrate. They will be instructed to apply it to both hands, twice daily. TAR-0520 gel applications will take place approximately one hour before each morning and evening capecitabine oral intake. Feet will be non-treated and will serve as controls.

During each chemotherapy Cycle (lasting 3 weeks), capecitabine will be administered for 14 days (BID regimen), followed by a 7-day treatment-free period. This dosing schedule corresponds to the standard-of-care regimen for capecitabine in patients receiving this chemotherapy as part of routine clinical practice.

TAR-0520 gel applications, BID to both hands will take place during the 14-day capecitabine treatment.From Day15 to Day21, neither capecitabine nor TAR-0520 gel will be administered.

TAR-0520 gel will be self-applied by patients or applied by somebody else (e.g. family member or caregiver) to the skin of both palmar and dorsal surfaces of both hands including fingers. Test product will be applied and massaged until full penetration.

In total, this study will follow patients during 4 capecitabine Cycles for a total of approximately 12 weeks of observation.

Evaluations will take place at Baseline (Day1 of the Cycle 1) and then at Day1 of the 2nd, 3rd, 4th and 5th (final visit) Cycle.

These evaluations will be conducted separately on hands and feet. During the evaluation visits, TAR-0520 gel safety will be evaluated with collection of adverse events and reactions.

The preventive efficacy will be assessed by measuring the incidence of grade 2 or higher HFS acording to NCI Common Terminology Criteria for Adverse Events (NCI-CTCAE) and via clinical grading of different HFS symptoms (numbness/tingling , pain, redness, swelling, bleesters, scalling/desquamation) on the scale 0-3 , 0-symptom absent,3-symptom severe.

The QoL will be assessed using HFS-14 questionnaire.

Inclusion Criteria:

• Medical diagnosis of breast or colorectal cancer planned to be treated with capecitabine
• at a dose > 1000mg/m² twice daily every 2 out of 3 weeks as single agent chemotherapy
• Patients with life expectancy graeter than 12 weeks

Exclusion Criteria:

• Patient with medical history of capecitabine treatment
• patient with pre-existing neuropathy confounding assessement of HFS
• Patient with Raynaud's syndrome or other vascular peripheral disorders
• Patient with dermatological lesions on hands or foot