X4 offers a place where patient-focus is our priority and encourage people who share this value to apply. We offer a team-based approach in a collegial environment. We place a high importance on individual career development to enable one to meet his or her professional goals.

Open Positions

Location: Boston, MA USA
Click here to view and apply for position openings at X4’s Boston location.

X4 is seeking key team members who:

  • Problem solve and who execute with high precision
  • Say what they mean, and let their words match their actions
  • Enjoy a team environment and foster direct and open communications

X4 is an equal opportunity employer and offers a comprehensive and competitive benefits package. Full-time employees are eligible for all benefits on their date of hire.

  • Health plan
  • Dental plan
  • Life/ADD insurance
  • Short- and long-term disability insurance
  • 401(k) plan for retirement savings
  • Subsidized parking or MBTA pass
  • Competitive Paid Time Off / Holidays


Location: Vienna, Austria

Scientist - Immunology

About X4 Pharmaceuticals

X4 is focused on restoring healthy immune system function by developing novel therapeutics for the treatment of rare diseases.

Our first-in-class, oral, small molecule therapeutics are antagonists of chemokine receptor CXCR4, which have the potential to treat a broad range of diseases including immune cell deficiencies and dysregulation. A number of these disorders are attributed to the improper trafficking of immune cells related to the CXCR4 receptor and its ligand CXCL12.

X4 Pharmaceutical’s lead product candidate, mavorixafor (X4P-001), is a potentially first-in-class, once-daily, oral inhibitor of CXCR4, currently in a Phase 3 clinical trial for the treatment of WHIM syndrome, a rare, inherited, primary immunodeficiency disease caused by genetic mutations in the CXCR4 receptor gene. Mavorixafor has demonstrated proof-of-concept in WHIM syndrome in a Phase 2 trial, including clinically meaningful increases in neutrophil and lymphocyte biomarker counts, as well as a trend of reduction in infection rates and wart burden, and a favorable safety profile. Consistent with the CXCR4-mediated immune cell dysregulation mechanism, Mavorixafor is also being developed to treat a broader patient population presenting with neutropenia (Severe Congenital Neutropenia; SCN) and with dysregulated B-cell development (Waldenström’s macroglobulinemia; WM). Mavorixafor was recently granted Breakthrough Therapy Designation by the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with WHIM syndrome and was granted orphan drug status by the FDA in 2018 and by the European Commission in 2019 for the treatment of WHIM syndrome.

X4’s research and development facility in Vienna, Austria, X4 Pharmaceuticals (Austria) GmbH is located on the Campus Vienna Biocenter (Helmut-Qualtinger-Gasse 2, 1030 Vienna) and is run by a team of highly motivated scientists and technicians who are dedicated to building a Center of Research Excellence in diseases where CXCR4 dysregulation drives Immune Cell Deficiencies. X4 Pharmaceuticals (Austria) GmbH is currently offering a full-time employment contract for a Scientist – Immunology.

Summary of the position:

We are looking for an experienced and highly motivated Scientist with a strong background in immunology. The ideal candidate will have a deep understanding in immune cell regulation and pathways, including experience working in diseases caused by immune cell impairments. Experience in infectious disease biology is a plus. The candidate will be involved in devising and conducting studies assessing immune cell function and disease, and efficacy of therapeutics, in cell and animal models. The selected candidate will also evaluate clinical/human specimens for the mechanistic characterization and efficacy of new therapies. The successful candidate will contribute to the identification, validation and characterization of novel targets and therapeutics, with a focus on primary immunodeficiencies. The main duties will include:

  • Perform in vitro and ex vivo assays to characterize primary immune and other cells, and the immune responses upon treatment with molecules.
  • Should the candidate have experience with conducting infection studies, the candidate may study the role of X4 molecules to treat pathogen infection in in vitro and/or in vivo models.
  • Support and perform immunological techniques e.g., multicolor flow cytometry, ELISA, ELISpot, cytokine assay and other immunoassays.
  • Develop and execute on in vitro and ex vivo assays including biomarker studies to support clinical trials and mode-of-action studies of X4 leading compounds.
  • Contribute to the identification and validation as well as project development processes for new therapeutic targets and indications
  • Collaborate with internal and external research teams and CROs to advance our research capabilities
  • Analyze and present data at internal and external meetings
  • Write reports and scientific publications

Qualifications and skills:

  • PhD degree in immunology, ideally neutrophil, B and T cell immunology or relevant field (e.g., immuno-oncology, hematology, or cell biology)
  • Extensive theoretical and experimental expertise in cellular and/or molecular immunology, especially related to neutrophil, B and T cell immunology
  • Expertise in infection biology (preferred) and disease animal models
  • Minimum of four years of post-doctoral and wet lab experience or corresponding industrial experience
  • Strength in research and interpretation of large datasets and cross-functional studies in various disease indications
  • Experience working within a Biosafety Level 2 laboratory including work with bacterial/viral pathogens and patient material
  • Effective communication and relationship building skills with internal and external stakeholders
  • Independent, proactive, and hands-on team player with strategic thinking and sense of urgency
  • Ability to supervise and train laboratory staff

We are offering:

  • A strong, dedicated, and multinational team of scientists and research assistants
  • An open, transparent, and collegial working environment
  • Opportunities for your personal and career development and to play a key role in a growing international research center

In accordance with Austrian employment law, the minimum gross salary p.a. for the position is EUR 48.690,60 which we will adjust according to your qualifications, skills and expertise.

Please send your cover letter referring to the position “Scientist – Immunology” and resume specifying your scientific expertise and technical skills in bullet point format in English to

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