The following criteria is provided for health care professionals.

Inclusion Criteria:

* Age ≥ 18 years
* MDS with IPSS-R very low, low, or intermediate risk features
* Symptomatic cytopenias
* Women of childbearing potential (WOCBP) must agree to use an oral or implanted contraceptive, a double-barrier method of birth control, or an intrauterine device upon enrollment and through 3 months after receiving the last dose of JSP191
* Women not of childbearing potential must be post-menopausal (no menstrual period for a minimum of 12 months) or surgically sterilized and have a negative serum pregnancy test upon study entry
* Male subjects must be surgically sterile or willing to use contraception upon enrollment and through 3 months after receiving the last dose of JSP191
* Must be willing and able to provide informed consent

Exclusion Criteria:

* Anemia secondary to iron deficiency, vitamin B12 deficiency, or folate deficiency
* Prior allogeneic or autologous stem cell transplant
* Known history of human immunodeficiency virus (HIV) (no laboratory testing is required), or active infection with hepatitis B or hepatitis C
* Pregnant women or women who are nursing and do not wish to discontinue breastfeeding
* Any other medical condition that, in the opinion of the Investigator, could pose a significant safety risk to the subject or jeopardize the integrity of the study
* Subjects who, in the opinion of the Investigator, may not be able to comply with the requirements of the study