A Study to Evaluate DMR-001 in Participants With CALR-mutant Myeloproliferative Neoplasms

Inclusion Criteria: * Signed informed consent, which includes compliance with the requirements and restrictions listed in the ICF and the protocol. * Diagnosis/confirmation of ET or MF as defined in the protocol. * Documented CALR exon-9 mutation. * Willingness to undergo bone marrow biopsy and aspiration per the Schedule of Assessments. Exclusion Criteria: * Presence of any malignancy unless participant has been disease free for at least 2 years. * History of major bleeding or thrombosis within the last 3 months prior to study enrollment. * Prior hematopoietic stem cell transplantation or donor leukocyte infusion, or such transplantation or infusion is planned. * Participants with laboratory values exceeding protocol defined thresholds. * History of clinically significant or uncontrolled cardiac disease. * Active HBV, HCV or HIV. * Known hypersensitivity to DMR-001 or ruxolitinib or any of their components. Other protocol defined Inclusion/Exclusion Criteria may apply.