Concierge Medicine in Gramercy Park, NY
Gramercy Park
Opening Spring 2026
Contact our Gramercy Park Concierge Medical Practice
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The MD² Gramercy Park office is scheduled to open in the spring of 2026.
Please contact us for more information about our unique model of concierge medicine and to reserve your spot on our pre-opening outreach list.
Concierge Doctors
Dr. Costas Hanjis, MD
Dr. Costas Hanjis is a highly respected internist with over 20 years of experience providing comprehensive, patient-centered care in New York City. A graduate of New York Medical College, he has built a distinguished career in internal medicine, primary care, and hospital medicine, with a particular focus on preventive health and chronic disease management.
Prior to joining MD², Dr. Hanjis served as an Attending Physician at both Weill Cornell Medical Associates and New York-Presbyterian/Weill Cornell Medical Center. Throughout his career, he has been recognized for fostering strong, enduring relationships with patients through a collaborative approach to care. Dr. Hanjis believes that truly getting to know his patients supports his holistic philosophy—creating lifestyle-focused plans that promote lifelong health and wellness and being available to help manage medical issues as they arise. His experience includes working with cancer survivors, guiding their medical and lifestyle needs with compassion and expertise. Whether navigating complex conditions or promoting preventive wellness, Dr. Hanjis brings clarity, empathy, and clinical excellence to every interaction. Dr. Hanjis is also known as the “doctor’s doctor,” a trusted physician to colleagues at Memorial Sloan Kettering and New York-Presbyterian, Weill Cornell.
In addition to his clinical practice, Dr. Hanjis is a dedicated educator. As a Clinical Assistant Professor of Medicine at Weill Cornell Medical College, he has mentored countless medical students and residents, earning a Teaching Award for his contributions to academic medicine at Weill Cornell Medical College. His dual commitment to practice and education reflects his belief that advancing healthcare begins with cultivating skilled, compassionate clinicians.
Dr. Hanjis is affiliated with several leading institutions, including New York-Presbyterian Hospital and Weill Cornell Medical Center. He is a longstanding member of the American Board of Internal Medicine and has maintained active certification since 2007.
A lifelong New Yorker, Dr. Hanjis brings the same passion and dedication to his personal life as he does to his medical practice. Outside the office, he is an avid sports fan with a particular love for Knicks basketball. He enjoys traveling with his family to regional and national soccer tournaments. He finds joy in music and playing the guitar and treasures family trips to Greece and Slovenia, where he reconnects with his heritage and creates lasting memories.
Dr. Melissa Sum, MD, FACE
Dr. Melissa Sum is a board-certified internist and endocrinologist, and a Fellow of the American Association of Clinical Endocrinology (FACE). She specializes in the management of longitudinal medical care as well as preventative and metabolic health. Based in New York City, she is known for her compassionate, evidence-based approach and dedication to improving long-term health outcomes and the well-being of her patients.
At the heart of Dr. Sum’s practice is a strong belief in partnership. She’s passionate about improving health and daily well-being by building meaningful relationships with her patients, grounded in trust, listening, and open dialogue. She takes time to understand each person’s goals and lifestyle, including nutrition, exercise, and values. She works collaboratively to create personalized care plans rooted in the latest science. She treats every patient with the same compassion she would offer a family member, creating a supportive environment where patients feel truly seen and heard—and empowered to take an active role in their long-term wellness.
Dr. Sum completed her undergraduate degree at Columbia College, graduating summa cum laude, Phi Beta Kappa with honors in chemistry. She earned her medical degree from Columbia University. She trained in internal medicine at Barnes-Jewish Hospital/Washington University, where she served an additional year as Medical Chief Resident. She returned to Columbia for a prestigious NIH Fellowship in Endocrinology, where she was selected as a Women's Health Scholar and worked at the Center for Menopause, Hormonal Disorders, and Women's Health. She then joined NYU and rose to the rank of Associate Professor. She served as Medical Director of the Diabetes and Endocrine Associates practice and Content Director of the endocrinology module for the first-year medical students at NYU Grossman School of Medicine.
In addition to her clinical work, Dr. Sum is a recognized leader in medical education. She has received multiple teaching honors, including NYU’s Rising Educator, Pre-Clerkship Educator of the Year, and Faculty Teacher of the Year awards. She remains actively involved in mentoring future physicians and finds particular joy in breaking down complex physiology pathways—a teaching approach that also enhances her ability to explain medical concepts clearly and compassionately to her patients. Whether managing complex internal medicine or endocrine disorders or guiding patients through preventive strategies, Dr. Sum is a trusted partner in health. She is respected for her clinical expertise, collaborative spirit, and unwavering dedication to patient-centered care.
Outside the office, Dr. Sum enjoys spending quality time with family and friends and reading a great book when time permits.
Dr. Costas Hanjis, MD
Dr. Costas Hanjis is a highly respected internist with over 20 years of experience providing comprehensive, patient-centered care in New York City. A graduate of New York Medical College, he has built a distinguished career in internal medicine, primary care, and hospital medicine, with a particular focus on preventive health and chronic disease management.
Prior to joining MD², Dr. Hanjis served as an Attending Physician at both Weill Cornell Medical Associates and New York-Presbyterian/Weill Cornell Medical Center. Throughout his career, he has been recognized for fostering strong, enduring relationships with patients through a collaborative approach to care. Dr. Hanjis believes that truly getting to know his patients supports his holistic philosophy—creating lifestyle-focused plans that promote lifelong health and wellness and being available to help manage medical issues as they arise. His experience includes working with cancer survivors, guiding their medical and lifestyle needs with compassion and expertise. Whether navigating complex conditions or promoting preventive wellness, Dr. Hanjis brings clarity, empathy, and clinical excellence to every interaction. Dr. Hanjis is also known as the “doctor’s doctor,” a trusted physician to colleagues at Memorial Sloan Kettering and New York-Presbyterian, Weill Cornell.
In addition to his clinical practice, Dr. Hanjis is a dedicated educator. As a Clinical Assistant Professor of Medicine at Weill Cornell Medical College, he has mentored countless medical students and residents, earning a Teaching Award for his contributions to academic medicine at Weill Cornell Medical College. His dual commitment to practice and education reflects his belief that advancing healthcare begins with cultivating skilled, compassionate clinicians.
Dr. Hanjis is affiliated with several leading institutions, including New York-Presbyterian Hospital and Weill Cornell Medical Center. He is a longstanding member of the American Board of Internal Medicine and has maintained active certification since 2007.
A lifelong New Yorker, Dr. Hanjis brings the same passion and dedication to his personal life as he does to his medical practice. Outside the office, he is an avid sports fan with a particular love for Knicks basketball. He enjoys traveling with his family to regional and national soccer tournaments. He finds joy in music and playing the guitar and treasures family trips to Greece and Slovenia, where he reconnects with his heritage and creates lasting memories.
Dr. Melissa Sum, MD, FACE
Dr. Melissa Sum is a board-certified internist and endocrinologist, and a Fellow of the American Association of Clinical Endocrinology (FACE). She specializes in the management of longitudinal medical care as well as preventative and metabolic health. Based in New York City, she is known for her compassionate, evidence-based approach and dedication to improving long-term health outcomes and the well-being of her patients.
At the heart of Dr. Sum’s practice is a strong belief in partnership. She’s passionate about improving health and daily well-being by building meaningful relationships with her patients, grounded in trust, listening, and open dialogue. She takes time to understand each person’s goals and lifestyle, including nutrition, exercise, and values. She works collaboratively to create personalized care plans rooted in the latest science. She treats every patient with the same compassion she would offer a family member, creating a supportive environment where patients feel truly seen and heard—and empowered to take an active role in their long-term wellness.
Dr. Sum completed her undergraduate degree at Columbia College, graduating summa cum laude, Phi Beta Kappa with honors in chemistry. She earned her medical degree from Columbia University. She trained in internal medicine at Barnes-Jewish Hospital/Washington University, where she served an additional year as Medical Chief Resident. She returned to Columbia for a prestigious NIH Fellowship in Endocrinology, where she was selected as a Women's Health Scholar and worked at the Center for Menopause, Hormonal Disorders, and Women's Health. She then joined NYU and rose to the rank of Associate Professor. She served as Medical Director of the Diabetes and Endocrine Associates practice and Content Director of the endocrinology module for the first-year medical students at NYU Grossman School of Medicine.
In addition to her clinical work, Dr. Sum is a recognized leader in medical education. She has received multiple teaching honors, including NYU’s Rising Educator, Pre-Clerkship Educator of the Year, and Faculty Teacher of the Year awards. She remains actively involved in mentoring future physicians and finds particular joy in breaking down complex physiology pathways—a teaching approach that also enhances her ability to explain medical concepts clearly and compassionately to her patients. Whether managing complex internal medicine or endocrine disorders or guiding patients through preventive strategies, Dr. Sum is a trusted partner in health. She is respected for her clinical expertise, collaborative spirit, and unwavering dedication to patient-centered care.
Outside the office, Dr. Sum enjoys spending quality time with family and friends and reading a great book when time permits.
For Your Consideration
There is a purity to MD2 you will not find elsewhere. At the heart of it, you are 1 of just 50 families who retain the services of a personal physician who knows you as well as their own family. The all-inclusive monthly fee is $2,500 for an individual and family members can be added at an additional cost. We do not bill insurance or Medicare. The MD2 fee ensures absolute, unlimited access to your physician, as well as their physician partner, and covers all care and services provided by the office.
Is there an annual contract for services?
We believe medical care should be based on a deeply meaningful relationship between a physician and a patient that ideally lasts a lifetime – not a contract. The only contract we use reflects our promise to you. It binds us to you, not the other way around. There is no obligation on your part. If for any reason you wish to depart MD2, you can cancel your services at any time without any financial commitment. Your doctor will graciously work with you to establish care with another physician of your choosing.
What services are included?
Simply put, every primary care service is included. There is no additional billing. To help you understand the term “primary care,” think of it as all the care and services required when you “go to your doctor.” But in this case, your doctor is a star internist who graduated at the top of their class and is regarded as the master diagnostician – an art that can be lost today, but never at MD2.
This includes such things as an extensive annual physical, unlimited visits, house and workplace calls, x-rays, routine lab tests and diagnostics indicated by your age, health, and conditioning status. These tests may include blood panels, cardiovascular screening, cancer evaluations, and whatever else your physician believes will promote your healthiest lifestyle. When you leave an MD2 office, you are never handed a bill for our services.
With unlimited time, your MD2 physician will go beyond the customary. They will guide you to appropriate consultants, specialists, and surgical services as needed and often accompany you to those appointments to ensure complete continuity of care. Your care is thorough and extensive yet always custom tailored.
Will my physician manage my care while I am traveling?
MD2 was explicitly designed to accommodate families who travel frequently and often live in a second residence for at least part of the year. Caring for highly mobile families is our specialty. Your physician will always remain your primary contact when you or your family travels; they will be your first call if you have a medical need and are prepared to care for you, regardless of your location. In addition, prepping for travel and planning your care while you are away will be a key element of your care. Should you fall ill or need medical attention while in another city with an MD2 office, your physician will coordinate care for you with their MD2 partner in that city. Lastly, as an MD2 patient, you are enrolled in a worldwide medical evacuation service, should you ever need it.
What if my physician goes on vacation?
We've set up each MD2 practice so that your physician or their partner will always be available to you. You will have direct access to both physicians’ private cell phones, which you can call anytime, day or night. If your physician is unavailable, you will have direct access to their MD2 partner physician. You will never have to go through a front desk, an obscure exchange service or even a nurse to get to your physician or their partner, even if they are on vacation.
What if I need to go to the hospital?
At MD2, you will never be left alone in your time of need. Shockingly, it has become customary today that physicians no longer follow patients during hospitalization. Instead, they leave their patients in the hands of hospitalists. At MD2 we believe this is unacceptable. MD2 physicians visit their patients while in the hospital and orchestrate care with medical specialists in any field. Should you require a hospital stay, your physician will be at your side as your advocate and quarterback.
Furthermore, if specific health services would be best provided at a medical center in another city, your MD2 physician will make all the arrangements for your stay and continue to be involved in overseeing your care.
Can my children join MD2?
As internists, we specialize in the care of adult patients, however, the age at which children transition out of pediatric care varies by individual. It’s a wonderful discussion to have with your MD2 physician. Please know that even when your child is under the care of their pediatrician, we welcome being involved and receiving questions. Multi-generational care is our specialty.