A Double-blind Study of Paclitaxel in Combination With Reparixin or Placebo for Metastatic Triple-Negative Breast Cancer

According to the cancer stem cell (CSC) model, tumors are initiated and maintained by a
cellular subcomponent that displays stem cell properties. These properties include
self-renewal, which drives tumorigenesis, and differentiation (albeit aberrant), which
contributes to tumor cellular heterogeneity. The existence of CSCs has been described in a
variety of haematologic and solid tumors including those of the breast, brain, colon,
pancreas, lung, liver, and head and neck.

In addition to driving tumorigenesis, CSCs may contribute to tumor metastasis as well as to
tumor recurrence after treatment. Although currently available drugs can shrink metastatic
tumors, these effects are usually transient and often do not appreciably extend the life of
patients. One reason for the failure of these treatments is the acquisition of drug
resistance by the cancer cells as they evolve; another non-mutually exclusive possibility is
that existing therapies fail to kill CSCs. The ability to shrink a tumor mass mainly reflects
an ability to kill bulk, non CSC tumor cells. This is because CSCs represent only a tiny
percentage of the total tumor cells in a neoplastic lesion and the majority of the bulk tumor
cells have limited proliferative potential. It seems that normal stem cells from various
tissues tend to be more resistant to chemotherapeutics than mature cell types from the same
tissues. The reasons for this are not clear, but may relate to high levels of expression of
anti- apoptotic proteins or ATP-binding cassette (ABC) transporters such as the multidrug
resistance gene. If the same were true of CSCs, then one would predict that these cells would
be more resistant to chemotherapeutics than bulk tumor cells with limited proliferative
potential. Even therapies that cause complete regression of tumors might spare enough CSCs to
allow regrowth of the tumors. Thus, therapies that are more specifically directed against
CSCs might result in much more durable responses and even cures of metastatic tumors.

The CSC (Cancer stem cell) concept has important implications for understanding
carcinogenesis as well as for the development of cancer therapeutics. According to this
concept, tumors are initiated and maintained by a cellular subcomponent that displays stem
cell properties. These properties include self-renewal, which drives tumorigenesis, and
differentiation (albeit aberrant), which contributes to tumor cellular heterogeneity. The
existence of CSCs has been described in a variety of hematologic and solid tumors including
those of the breast, brain, colon, pancreas, lung, liver, and head and neck. In addition to
driving tumorigenesis, CSCs may contribute to tumor metastasis as well as to tumor recurrence
after treatment.

One of the therapeutic strategies being pursued to target CSCs involves inhibition of self
renewal or survival pathways in these cells. These pathways include NOTCH (Notch signaling
pathway), Hedgehog, and WNT (Wnt signaling pathway). Such strategies may be limited by the
role of these pathways in normal stem cell function, which could result in systemic
toxicities from pathway inhibition. In addition to intrinsic pathways regulating stem cell
functions, normal and malignant stem cells are regulated by extrinsic signals generated in
the microenvironment or CSC niche. In the breast, this niche is composed of immune cells,
mesenchymal elements that include fibroblasts, endothelial cells, adipocytes, and
extracellular matrix components. These components play an important role in normal breast
development and carcinogenesis. If the cellular microenvironment plays an important role in
the regulation of CSC growth and survival, then strategies aimed at interfering with these
interactions represent a rational approach to target breast CSCs.

There are limited data on the impact of treatment tailoring based on CSCs detection. Gene
profiling of CSCs could lead to identification of therapeutic targets on CSCs (e.g. hormone
receptors, HER-2 [Human epidermal growth factor receptor-2] expression, EGFR [Epidermal
growth factor receptor] expression), and could represent tumor biopsy in "real time". Several
groups showed frequent discordance of HER-2 status between primary tumor and CSCs, and case
reports showed clinical utility to use of trastuzumab-based therapy based on HER-2 CSCs
status. Similarly, the hormonal status of CSCs could be different from that of the primary
tumor, which could lead to increase the number of patients suitable for endocrine therapy,
but also could explain why endocrine therapy fails in a subset of hormone receptor-positive
patients. The study provided the in vivo demonstration that CXCR-1 (Chemokine receptor 1)
targeting with specific blocking antibodies or reparixin is associated with reduced systemic
metastases. The experimental data provides another therapeutic target in metastatic disease
and warrants a pilot study investigation in humans to further explore effects of reparixin on
breast CSCs and the tumoral microenvironment.

Reparixin seems to be a good candidate for use in breast cancer patients because of its very
acceptable toxicity profile shown in the Phase I and II clinical trials conducted so far,
along with its observed activity in vitro against breast cancer cell lines and in vivo in
tumor xenografts in mice. It potentially addresses another therapeutic target in metastatic
disease. The current phase 2 study thus aims to evaluate the Progression Free Survival of
patients with metastatic TNBC [newly diagnosed metastatic or relapsed following (neo)adjuvant
chemotherapy] receiving reparixin in combination with paclitaxel versus paclitaxel alone.

Inclusion Criteria:

1. Female aged ≥ 18 years.

2. Patients with pathologically documented metastatic triple negative breast cancer
(TNBC), eligible for treatment with paclitaxel. Paraffin-embedded tissue must be
available from metastatic sites, if reasonably accessible, or from the primary tumor,
to confirm the diagnosis of TNBC and for correlative studies (only on metastatic
tissue). Fifteen slides can be obtained if the full block is not available to be sent
or released.

TNBC will be defined as breast cancer with <1% ER+ and <1% PgR+ cells, and HER2
immunohistochemistry score of 0 or 1+ and/or in situ hybridization (ISH) with HER2
gene copy number <4 or a ratio of less than 2 between HER2 gene copy number and
centromere of chromosome 17. Patients whose metastatic disease is TNBC are eligible
even when their primary tumor expressed hormone receptors and/or HER2.

3. Patients must be newly diagnosed metastatic or must have relapsed following a prior
(neo)adjuvant chemotherapy regimen. If a taxane (i.e., paclitaxel or docetaxel) was
administered as part of the (neo)adjuvant regimen, PD must have occurred > 12 months
from the end of previous (neo)adjuvant treatment. For non-taxane (neo)adjuvant
regimen, PD must have occurred > 6 months from the end of previous (neo)adjuvant
treatment

4. Patients with at least one baseline measurable lesion according to RECIST criteria
version 1.1.

5. Zubrod (Eastern Co-operative Oncology Group [ECOG]) Performance Status (PS) of 0-1.

6. Life expectancy of at least three months.

7. Patients must be able to swallow and retain oral medication (intact tablet).

8. Able to undergo all screening assessments outlined in the protocol.

9. Adequate organ function (defined by the following parameters):

1. Serum creatinine < 140 μmol/L (< 1.6 mg/dL) or creatinine clearance > 60 mL/min.

2. Serum hemoglobin ≥ 9 g/dL; absolute neutrophil count ≥ 1.5 x 109/L; platelets ≥
100 x 109/L.

3. Serum bilirubin ≤ 1.5 x upper normal limit (UNL) except patients with Gilbert's
syndrome

4. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) ≤ 2.5 x
UNL but ≤ 5.0 x UNL in case of liver metastases; alkaline phosphatase (ALP) ≤ UNL
but i) ≤ 2.5 x UNL in case of liver metastases and ii) ≤ 5 UNL in case of bone
metastases; albumin ≥ 2.5 g/dl.

10. No history or evidence by CT scan or MRI, of brain metastases or leptomeningeal
disease.

11. No known hepatitis B virus (not due to immunization), hepatitis C virus, human
immunodeficiency virus-I and -II positive status.

12. Dated and signed IEC/IRB-approved informed consent.

Exclusion Criteria:

1. Prior therapy for metastatic TNBC (chemotherapy, hormone therapy or biological
therapy), Patients may receive bisphosphonates and other therapies to treat bone
metastases, however if used, bone lesions will not be considered as measurable
disease.

2. Less than four weeks since last radiotherapy (excluding palliative radiotherapy).

3. Pregnancy or lactation or unwillingness to use adequate method of birth control.

4. Neurological or psychiatric disorders which may influence understanding of study and
informed consent procedures.

5. Active or uncontrolled infection.

6. Malabsorption syndrome, disease significantly affecting gastrointestinal function.

7. G>1 pre-existing peripheral neuropathy

8. Any other invasive malignancy from which the patient has been disease-free for less
than 5 years with the exception of curatively treated basal or squamous cell skin
cancer

9. Hypersensitivity to:

1. paclitaxel

2. ibuprofen or to more than one non-steroidal anti-inflammatory drug.

3. medications belonging to the class of sulfonamides, with the exception of
sulfanilamides (e.g., sulfamethoxazole).