The study will be conducted in two phases. The phase I portion will employ a 3+3 dose-escalation design to define the maximum tolerated dose (MTD) of abatacept added to PTCy and bortezomib following HSCT. The phase II portion will consist of two single-arm, open-label, optimal 2-stage Simon design studies conducted in two separate strata for HLA-matched and HLA-mismatched donor transplants.
Age ≥18 years
Karnofsky score ≥70%
No evidence of progressive bacterial, viral, or fungal infection
Creatinine clearance >50 mL/min/1.72m2
Pregnant or nursing females or women of reproductive capability who are unwilling to completely abstain from heterosexual sex or practice effective methods of contraception from start of conditioning through 90 days after the last dose of study drug. A woman of reproductive capability is one who has not undergone a hysterectomy (removal of the womb), has not had both ovaries removed, or has not been post-menopausal (stopped menstrual periods) for more than 24 consecutive months.
Male subjects who refuse to practice effective barrier contraception from the start of conditioning through a minimum of 90 days after the last dose of study drug, or completely abstain from heterosexual intercourse. This must be done even if they are surgically sterilized.
Inability to provide informed consent.
Patient had myocardial infarction within 6 months prior to enrollment or has NYHA Class III or IV heart failure, uncontrolled angina, severe uncontrolled ventricular arrhythmias, or electrocardiographic evidence of acute ischemia or active conduction system abnormalities. Prior to study entry, any ECG abnormality at screening must be documented by the investigator as not medically relevant.