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Clinical Data for X4P-001-IO in Combination with Inlyta® (Axitinib) Demonstrated Encouraging Overall Response Rates (Including a Complete Response) and Disease Control Rates in Patients with Clear Cell Renal Cell Carcinoma


Phase 1 dose escalation completed and enrollment in Phase 2 expansion

, a clinical stage biotechnology company developing a
novel CXCR4
to improve immune cell trafficking to treat cancer and
rare diseases, today announced updated results from the Phase 1 part of
an ongoing Phase 1/2 study of X4P-001-IO
in combination with Inlyta® (axitinib) in patients with clear
cell renal cell carcinoma (ccRCC).

The results in patients with ccRCC who received the combination
treatment of X4P-001-IO, a CXCR4 inhibitor, and Inlyta, Pfizer's VEGFR
kinase inhibitor, showed an objective response rate (ORR) of 29%,
including 1 patient achieving a confirmed complete response (CR), with
an encouraging disease control rate (DCR) of 93%. 31% of patients
entering the study had received one prior line of therapy while the
majority of patients (69%) had received at least two prior lines of
therapy. The data were presented at the 2017
AACR-NCI-EORTC Molecular Targets and Cancer Therapeutics Conference

on October 29 in Philadelphia.

"The combination of CXCR4 inhibition and VEGFR inhibition shows
promising clinical results in this very difficult to treat population of
patients with ccRCC. These results suggest that X4P-001-IO may address
some of the limitations and augment the clinical utility of axitinib,
which is a clinically meaningful drug in the treatment of patients with
advanced metastatic ccRCC," said Michael Atkins, MD, Deputy Director,
Georgetown Lombardi Comprehensive Cancer Center, William M. Scholl
Professor of Oncology at Georgetown University School of Medicine, and
lead investigator of the study. "These results, while early, are very
promising with a strong disease control rate and a manageable safety

Results from the 16 patients with advanced ccRCC enrolled in the dose
escalation part of the ongoing Phase 1/2 study as of the data cutoff
date of October 2, 2017 were presented and highlights of the poster
presentation include:

  • The combination of X4P-001-IO and Inlyta showed one confirmed complete
    response (CR) and produced a DCR and ORR of 93 percent (13/14) and 29
    percent (4/14), respectively, in the evaluable patient population.
  • The median duration on treatment at the data cutoff was 22.1 weeks and
    44 percent of patients had been exposed to study treatment for at
    least 24 weeks.
  • X4P-001-IO in combination with Inlyta was considered to be safe and
    generally well tolerated. The most frequent treatment-related adverse
    events (AEs) were hypertension, diarrhea, fatigue, nausea, decreased
    appetite, headache and dry eye. No grade 4 or 5 AEs were observed.
  • Pharmacodynamic (PD) measurements demonstrated that the 400 mg dose
    inhibited the intended target chemokine receptor CXCR4.
  • Based on the study results, a dose of 400 mg X4P-001-IO once daily
    with 5 mg Inlyta twice daily has been selected for the Phase 2 portion
    of the ongoing Phase 1/2 study.

"We are encouraged by the results to date in this first cohort of
patients, many of whom have been on study for over six months and have
seen early signs of clinical efficacy with manageable side effects,"
said Sudha Parasuraman, MD, Chief Medical Officer of X4. "We look
forward to sharing a comprehensive update on the ongoing Phase 2a
clinical trial, as well as the path forward for further development, in

The Phase 2 portion of the study continues to enroll patients to
evaluate the clinical efficacy of X4P-001-IO as measured by objective
response rate (ORR), duration of response (DOR), and progression free
survival (PFS), as well as explore the correlation of biomarkers with
efficacy. (

About X4P-001-IO in Cancer

is an investigational selective, oral, small molecule inhibitor of CXCR4
(C-X-C receptor type 4) that regulates the tumor microenvironment
thereby enhancing endogenous anti-tumor responses. CXCR4 is a chemokine
receptor that modulates immune function and angiogenesis through the
trafficking of key immune cells such as T-cells, dendritic cells, and
myeloid derived suppressor cells. CXCR4 signaling is disrupted in a
broad range of cancers, facilitating tumor growth by allowing cancer
cells to evade immune detection and creating a pro-tumor

About Renal Cell Carcinoma

Kidney cancer is among the ten most common cancers in both men and women
with more than 60,000 new diagnoses each year in the United States.1
Clear cell renal cell carcinoma (ccRCC) is the most common form of
kidney cancer, and advanced ccRCC accounts for approximately 20% of the
patient population. Therapies for advanced ccRCC include
immunotherapies, mammalian target of rapamycin (mTOR) kinase inhibitors,
and angiogenesis inhibitors, such as vascular endothelial growth factor
(VEGF) inhibitors.2 There continue to be unmet medical needs
with advanced ccRCC because durable responses remain a serious clinical
challenge for patients with advanced disease.

About X4 Pharmaceuticals

is developing novel therapeutics designed to improve
immune cell trafficking to treat cancer and rare diseases. The Company's
oral small molecule drug
inhibit the CXCR4 receptor, a pathway which plays a
central role in immune surveillance. X4's most advanced product
candidate, X4P-001-RD,
is in a Phase 2/3 study in patients with WHIM syndrome, a rare genetic,
primary immunodeficiency disease. X4P-001-IO
is currently under investigation in multiple Phase 1/2 studies in
refractory clear cell renal cell carcinoma (ccRCC) and melanoma. X4 was
founded and is led by a team
with deep product development and commercialization expertise, including
several former members of the Genzyme leadership team, and is located in
Cambridge, MA.

1 National Cancer Institute, "Surveillance, Epidemiology, and End
Results Program,"

2 Kidney Cancer Association, "Therapies for Advanced Kidney Cancer,"

® Inlyta is a registered trademark of Pfizer, Inc.

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