Temperature curves and peri-engraftment symptoms. (A) All temperature readings over the course of the first 21 days for all phase 1 patients are shown. Fevers were more common for patients in DL3 (PTCy 25 mg/kg on day +4 only) and were noted to be higher and more prolonged beyond the time of engraftment. (B) Fevers, rash, and transaminitis were common during the peri-engraftment period for all 3 dose levels, but engraftment syndrome criteria were met only by 3 patients: 1 at DL2, and 2 at DL3 (all 3 with fever, rash, and transaminitis); none of these patients required treatment for engraftment syndrome and the symptoms quickly improved without intervention. ^aIncludes 1 patient with prolonged engraftment time and fevers early in course of neutrophil recovery (>4 days from day of engraftment); ^b1 patient with symptoms that were attributable to sinusoidal obstructive syndrome. This patient was the first DL3 patient and had severe and rapid increase in transaminases along with concomitant fever on day +10 and received 1 dose of tocilizumab before it was determined that he was having sinusoidal obstruction syndrome during this peri-engraftment period as the cause of the transaminase elevation. This was the only patient with immunosuppressive treatment before day +21 beyond the intended PTCy, sirolimus, and mycophenolate mofetil.