Skip to content



Image of Isaac Ciechanover, M.D.

Dr. Isaac Ciechanover is a physician, investor and entrepreneur driven by a passion to improve the practice of medicine. Motivated by the belief that the majority of medical discoveries still lie ahead, he has dedicated the past 20 years to working with entrepreneurs and life sciences organizations to advance medicine through innovation and technology. He founded Atara Biotherapeutics in August 2012. Previously, he was a partner in the life sciences practice at Kleiner Perkins Caufield & Byers. Earlier as Celgene’s Executive Director for Business Development, he spearheaded the company’s venture capital efforts and led licensing and M&A activities with an aggregate value of more than $6.7 billion. Also at Celgene, he was Global Project Leader for the company’s first clinical-stage biologic therapy. Isaac has also held business development and venture capital roles at Amylin Pharmaceuticals, Pequot Ventures’ healthcare practice and Pfizer. Intellectually curious (and undeterred by student debt), Isaac holds a B.A.  from Stanford University, an M.Phil. in Epidemiology from Cambridge University, an M.D. from Weill Cornell Medical College and an M.B.A. from Harvard Business School. For fun, he enjoys cycling, scuba diving and building Lego with his two children. His all-time favorite albums are Pink Floyd’s “The Dark Side of the Moon,” Radiohead’s “OK Computer” and Ruggero Leoncavallo’s Italian opera, Pagliacci, with Herbet Von Karajan conducting.

Image of Mitchall G. Clark

Mitch Clark is the Chief Regulatory and Quality Assurance Officer at Atara Biotherapeutics with responsibility global regulatory strategy and quality assurance. Mitch has over 30 years of global Regulatory Affairs, Quality Assurance, and Drug Development experience in the pharmaceutical industry. His professional experience includes senior management roles at a number of organizations such as Schering AG (based in its UK and Berlin offices), American Pharmaceutical Partners (APP), Abraxis Bioscience, Celgene Corporation, and NantPharma, LLC.

Among his significant previous positions, Mitch served as the Senior Vice President, Regulatory Affairs at NantPharma, LLC where he established the Regulatory Affairs and Quality Assurance functions. He was Senior Vice President of Global Regulatory Affairs at Abraxis where he created and managed the regulatory team responsible for filing the initial IND and obtaining the global regulatory approvals of Abraxane®, the first albumin-bound nanoparticle product for the treatment of solid tumors.

Earlier in his career, he worked for large and small organizations. Most notably, he gained valuable international experience in positions of increasing responsibility with Schering AG, working in the Berlin head office and UK subsidiary where he played a key role in the global approvals of the first-in-class gadolinium-based MRI contrast agent, Magnevist®.

Mitch holds a B.Pharm from The University of Nottingham, England. He enjoys a wide range of outdoor pursuits including canoeing, sailing and motorcycling.

Image of Christopher Haqq, M.D., Ph.D.

Dr. Christopher Haqq joined Atara Biotherapeutics as Chief Medical Officer in September 2012. He brings 20 years of clinical, academic and drug development experience from biopharma companies large and small. He was recently Vice President for Clinical Research and Development at Cougar Biotechnology and Johnson & Johnson’s Janssen, where he was the lead clinician for a pivotal prostate cancer study leading to market approval for Zytiga® (abiraterone acetate). Previously at Amgen, he led early development studies of the anti-insulin like growth factor type 1 receptor AMG 479 (ganitumab) antibody. He has served as medical monitor for more than 10 clinical trials and has contributed to drug development programs for a wide range of molecules. Chris has worked closely with the European Medicines Agency, the U.S. Food and Drug Administration and other global regulatory agencies–filing IND applications, new drug applications, special protocol assessments and their international equivalents. Earlier in his career, Chris practiced as a medical oncologist and led a translational science laboratory as an Assistant Adjunct Professor in the Division of Hematology/Oncology at the University of California, San Francisco. In his post-graduate training, also at UCSF, he served as an Intern and Resident in Internal Medicine, Fellow in Medical Oncology and Fellow in Molecular Medicine. Chris completed his M.D. and Ph.D. at Harvard Medical School and his B.S. at Stanford University. He is board certified in Medical Oncology and Internal Medicine. Chris is an inventor of three patents and an author of nearly 50 medical publications. In his free time, he enjoys astronomy and photography.

Image of John F. McGrath, Jr.

John F. McGrath, Jr. joined Atara Biotherapeutics as Chief Financial Officer in January 2013. He was previously Executive in Residence and Operating Partner at Kleiner Perkins Caufield & Byers. John was also Vice President and Chief Financial Officer for Network Equipment Technologies, Inc., which developed and sold network equipment for real-time communications. Earlier in his career, he was Vice President of Finance for Aspect Communications, Director of Finance for TCSI Corporation and Manager in the High Technology and Manufacturing practice at Ernst & Young. John is a registered C.P.A. (inactive) in California and earned a B.S. from the University of Wyoming and an M.B.A. from the Stanford Graduate School of Business. John has served on the board of the Presidio Fund, a publicly traded mutual fund, and as Audit Committee Chairman on the boards of Actel Corporation and Endwave Corporation. Away from work, John enjoys running (including three marathons), swimming and traveling.

Image of Gad Soffer

Gad Soffer joined Atara Biotherapeutics in March 2013 as Chief Operating Officer. Previously at Celgene, he led the global project team responsible for product development and lifecycle management for Abraxane, a breast, lung, and pancreatic cancer treatment also in development for melanoma. He also led numerous business development transactions at Celgene while advising on venture investment and strategic partnerships. Earlier, Gad was a healthcare consultant with Easton Associates. He earned an M.B.A. at Harvard Business School, an M.S. at Columbia University and an A.B.from Harvard University. In his free time, Gad enjoys geology, fly-fishing, canoeing and snowshoeing. In 2001, he was inducted in the National Wrestling Hall of Fame.

Image of Heather D. Turner

Heather D. Turner joined Atara Biotherapeutics in July 2015 as Vice President, General Counsel and Secretary. At Atara Bio she is responsible for legal, human resources, medical affairs and facilities functions. From June 2007 to June 2015 she was first a Vice President and later Senior Vice President, General Counsel and Secretary at Orexigen Therapeutics, Inc. where she led various G&A functions including legal, human resources, risk management, compliance and facilities. Prior to Orexigen, from July 2005 to June 2007, Heather worked first as Corporate Counsel and later as Associate General Counsel at Conor Medsystems, LLC (previously Conor Medsystems, Inc.), a medical device company specializing in drug-eluting stents. From 1999 until 2005, Heather was an associate in the corporate securities group at Cooley LLP (formerly Cooley Godward LLP), a leading national law firm. Throughout her career, Heather has advised public and private life science companies on matters ranging from public reporting, public offerings, securities law compliance, mergers and acquisitions, commercial, manufacturing and development contracts, corporate governance, board and committee duties and other general corporate matters. Ms. Turner received a J.D. from the UCLA School of Law, and a B.A. from University of California, Santa Barbara where she graduated with honors and was elected Phi Beta Kappa. Ms. Turner is a member of the State Bar of California. In her free time, Heather enjoys skiing, cooking and traveling.

Image of Joe Newell
Joe Newell joined Atara Biotherapeutics as the Chief Technical Operations Officer in April 2017 with global responsibility for Technical Operations and Facilities. 
Prior to joining Atara, he was Vice President, North America Manufacturing at Alexion Pharmaceuticals a company dedicated to treating patients with life-threatening ultra-rare disorders.  He was responsible for bulk drug substance production of Soliris® and the transgenic manufacturing operations for Kanuma®, the only FDA-approved treatment for lysosomal acid lipase deficiency (LAL-D).
Previously, Joe spent several years at Amgen where he served in a number of global leadership roles in Manufacturing and Supply Chain, including an expatriate leadership assignment in Puerto Rico, where he was part of launch efforts for Prolia®, Xgeva® and Repatha®.  Earlier in his career, he held leadership and entrepreneurial roles with Catalent Pharma Solutions, Matrix Pharmaceutical and SRI International.
Joe holds a BS in Biology from California Polytechnic University, Pomona.  Away from work, he is dedicated to his wife and three children.  For fun, he enjoys the outdoors, sports and a variety of restoration projects.  
Image of Steve Bertram

Steve Bertram joined Atara Biotherapeutics in August 2016 as the Head of Global Human Resources.  Prior to joining Atara, Steve was with Amgen where he held a number of business facing HR executive level roles with both domestic and global accountabilities and staff.  Functional areas of HR leadership included Global Development, Global Commercial, Translational Sciences, Discovery Research, and Technical Operations.  

Prior to Amgen, Steve was with the Coca-Cola organization in Atlanta supporting their flagship global Marketing team.  Steve began his career with The Upjohn Company in Kalamazoo, Michigan holding roles of increasing accountability in corporate, commercial and international organizations.  Steve holds a BBA from Western Michigan University in Business and an MBA from Michigan State University. 

Away from work, Steve enjoys time with his wife and three kids.  For fun he enjoys scuba diving, canoeing in Michigan, attending sporting events and travel.

Image of AJ Joshi

Dr. Manher (AJ) Joshi joined Atara Biotherapeutics in August 2016, and serves as its Senior Vice President, Global Medical Affairs. At Atara Bio, AJ is responsible for global medical affairs and the health outcomes and market access research functions.  He brings over 15 years of clinical, drug development and commercialization experience in orphan and large markets.  He has built and led medical organizations through several launches across a broad range of therapeutics areas including neuromuscular disease, neurosciences, genetics, metabolic diseases, urology, and dermatology. AJ’s previous medical affairs and organizational leadership roles include US Medical Affairs Therapeutic Area Head at Allergan, SVP Strategic Development and Medical Operations at Synageva, and Vice President Medical Affairs and Operations at Genzyme. Dr. Joshi received his MD from the Boston University School of Medicine, his BA from Boston University, and completed his Internship and Residency in Medicine at Yale. In his free time, AJ enjoys photography, traveling, and playing the guitar.