13 September 2017 - - US-based clinical stage biotechnology company X4 Pharmaceuticals has released Phase 1 results from the company's ongoing Phase 1/2 study of X4P-001-IO.

The company is developing a novel CXCR4 inhibitor drug to improve immune cell trafficking to treat cancer and rare diseases.

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 were presented at the ESMO 2017 Congress on Sunday, September 10.

All patients had received at least one prior line of therapy and 69 % of patients have received at least two prior lines of therapy. Highlights of the poster presentation include:

In the evaluable patient population, the combination of X4P-001-IO and Inlyta produced a disease control rate and objective response rate of 92% (11/12) and 25 %, respectively, including three partial responses.

The median duration on treatment was 14.7 weeks and 43 % of patients had been exposed to study treatment for at least 24 weeks.

X4P-001-IO in combination with Inlyta was generally well tolerated. The most frequent treatment-related adverse events in patients receiving X4P-001-IO at 200 mg twice daily, 400 mg once daily, or 600 mg once daily were diarrhea, hypertension, fatigue, nausea, headache, decreased appetite, and vomiting. No grade 4 or 5 AEs occurred.

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.

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, duration of response, and progression free survival, as well as exploring the correlation of biomarkers with efficacy.

X4P-001-IO 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 microenvironment.

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.

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 kinase inhibitors, and angiogenesis inhibitors, such as vascular endothelial growth factor inhibitors.

There continue to be unmet medical needs with advanced ccRCC because durable responses remain a serious clinical challenge for patients with advanced disease.

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 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, Massachusetts.