Panitumumab Skin Toxicity Prevention Trial

Background and rationale: EGFR represents the main and more studied signal activation pathway in the development of colorectal carcinoma. KRAS, NRAS, BRAF and PI3KA mutations and ERBB2 and MET amplification are responsible for most of the cases of primary resistance to anti-EGFR antibody treatments. Despite the identification of these resistance mechanisms, a primary resistance to the therapy was detected in a certain percentage of cases, in which tumour bio-molecular characteristics would suggest a possible response to anti-EGFR antibody treatment. In these cases, pathway activation mechanisms should exist, which act in an alternative, complementary or parallel way than the EGFR one, allowing tumour progression despite of EGFR pharmacological deactivation. Skin toxicity is a characteristic of drugs having EGFR as a target and it shows itself mainly as a sterile acneiform folliculitis together with neutrophils perifollicular infiltrates but also as skin xerosis and paronychia starting from the earliest cycles of treatment. This skin toxicity seems to be closely related to EGFR activation of pro-inflammatory cytokines able to activate specific inflammatory activators, which induce neutrophils granulocytes chemotaxis. Lycopene is a compound belonging to carotenoid group, largely contained in tomatoes and their derivatives, which has an extreme antioxidant activity. In Dermatology, prolonged use of β-carotenoids in general and of lycopene in particular in the diet showed to be effective in skin protection from ageing, sunlight and radiotherapy damages because these compounds may accumulate in skin and thus contribute to reduce free radicals and inflammation effects. Moreover, lycopene ability to induce apoptosis and to inhibit cell cycle progression in some types of tumour cells, both in vitro and in vivo, has already been described. Lycopene seems to be able to suppress significantly PCNA (Proliferating cell nuclear antigen, cofactor of DNA polymerase-β) and β-catenin nuclear expression in neoplastic cells, essential substrate of WNT/β-catenin pathway, which is itself closely connected to activating pathways often involved in carcinogenesis of some kinds of tumours, in particular of colorectal carcinoma, like Akt/GSK3β/β-catenin and Hippo pathways. For its proved skin anti-inflammatory activity as powerful free radicals scavenger, lycopene, which accumulates itself specifically in skin, could be effective in reducing anti-EGFR drugs toxicity. Contemporary use of lycopene could have a positive effect on anti-EGFR drugs treatment effectiveness in patients with metastatic colorectal carcinoma due to its ability to interfere with pathways involved in neoplastic cells proliferation.

Estimated population:100 patients (50 for each of the two groups of treatment)

Study Framework: In this study, patients suffering from metastatic colorectal cancer and submitted to therapy with panitumumab would be enrolled. According to indications, panitumumab would be used:

in first line combined with Folfox or Folfiri;

in second line combined with Folfiri or treatments containing Irinotecan

in monotherapy in any therapeutic line in patients resistant to Fluoropyrimidines, Oxaliplatin and Irinotecan or intolerant to these drugs.

Standard schedules of these treatments would be used.

This is a phase-II, randomized, double-blind study between experimental prophylactic treatment with Lycopene vs placebo:

- Treatment A - lycopene tablets 20 mg

- Treatment B - placebo tablets

Patients should take orally Lycopene/placebo after dinner (to promote its absorption), starting the day before the beginning of treatment with panitumumab for the entire duration of the therapy, until progression of the disease or definitive drug suspension for toxicity.

Objectives of the study

Primary objective: to assess the effectiveness of lycopene versus placebo in reducing skin toxicity induced by panitumumab in patients treated for metastatic colorectal carcinoma.

Secondary objective: to assess lycopene pharmacokinetics

Exploratory objectives: to assess lycopene effectiveness versus placebo in increasing panitumumab effectiveness in terms of Disease Control (DC), Objective Response (OR) and Stabilisation of the Disease (SD). To assess lycopene effectiveness versus placebo in increasing panitumumab effectiveness in terms of Progression Free Survival (PFS).

As far as randomization is concerned, the two groups will be balanced according to sex, therapeutic line and institution in which patients will be treated.