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X4 Pharmaceuticals Reports Positive Clinical Data from Phase 2 Expansion Study of X4P-001-IO and Axitinib in Patients with Clear Cell Renal Cell Carcinoma


Favorable response rates and combinability demonstrated in heavily
pretreated patients

Results presented at the 2018 American Society for Clinical Oncology
(ASCO) Annual Meeting

X4 Pharmaceuticals, a clinical stage biotechnology company developing
novel CXCR4 antagonists to improve immune cell trafficking to treat
cancer and rare diseases, today announced positive clinical results from
the Phase 2 expansion 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 were the first from the Phase 2 portion of the study and
demonstrated that the combination was well tolerated with a manageable
safety profile and had encouraging response in heavily pretreated
patients. In patients with ccRCC, the combination treatment of
X4P-001-IO, a CXCR4 antagonist, and Inlyta, Pfizer's VEGFR kinase
inhibitor, showed an objective response rate (ORR) of 23%, including 1
patient with a confirmed complete response (CR). Nearly 75% of patients
received at least two prior lines of therapy prior to entering the
study. The data were presented at the 2018 American Society of Clinical
Oncology (ASCO) Annual Meeting on June 2nd in Chicago, IL.

"X4P represents a novel targeted mechanism of action with demonstrated
tolerability and promising efficacy in combination with axitinib in
patients with pretreated renal cancer. The results from this study
demonstrate that X4P-001-IO has the potential to enhance clinical
responses to axitinib and other tyrosine kinase inhibitors that target
tumor angiogenesis," said Ulka Vaishampayan, MD, Chair, Karmanos Cancer
Center, Professor of Oncology at Wayne State University, and lead
investigator of the study.

Results from the 65 patients with advanced ccRCC enrolled in the ongoing
study (as of the data cutoff date of March 23, 2018) were presented at
ASCO and highlights of the poster presentation include:

  • The combination of 400 mg X4P-001-IO administered once daily and 5 mg
    axitinib twice daily was well tolerated with a manageable safety
    profile. The most frequent treatment-related adverse events (AEs) were
    diarrhea, decreased appetite, fatigue, hypertension, nausea, headache
    and cough. No grade 4 or 5 AEs were observed.
  • In the 47 evaluable patients, the overall response rate (ORR) was 23%
    with one patient achieving a confirmed complete response (CR).
    Response data from the remaining 18 patients is pending.
  • Thirteen patients remain on study for 24 weeks or more; the median
    duration on treatment was 16 weeks (range 2 – 96 weeks).

"These interim results represent an important step in the continued
development of X4P-001-IO. In this larger patient population, where many
patients are still very early in treatment with the combination, we find
promising signs of clinical efficacy. The tumor microenvironment
modulating effect of X4P-001-IO is expected to increase and deepen
responses over time, and we look forward to the maturation of the data
in the coming months," said Sudha Parasuraman, MD, Chief Medical Officer
of X4. "Our combined clinical experience continues to demonstrate the
important role that CXCR4 antagonism may play in improving outcomes in
combination with important cancer therapeutic modalities."

The Phase 2 portion of the study continues to follow patients on study
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). (

About X4P-001-IO in Cancer

X4P-001-IO is an investigational selective, oral, small molecule
antagonist of C-X-C receptor type 4 (CXCR4). CXCR4 is a chemokine
receptor present in abundance on certain immune cells and cancer cells
and it plays a critical role in immune cell trafficking, infiltration
and activation in the tumor microenvironment. 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
microenvironment. X4P-001-IO has the ability to help restore immunity
within the tumor microenvironment and has the potential to enhance the
anti-tumor activity of approved and emerging oncology agents, such as
checkpoint inhibitors and targeted therapies. X4P-001-IO is being
investigated in several clinical studies in solid tumors.

About X4 Pharmaceuticals

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 candidates antagonize the CXCR4 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 clinical studies in solid
tumors. 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.
For more information, visit

Inlyta® is a registered trademark of Pfizer, Inc.

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