Adding plinabulin to prophylactic pegfilgrastim and antibiotics may help prevent nonengraftment–related febrile neutropenia.
Patients with multiple myeloma who have received high-dose melphalan and have undergone autologous hematopoietic stem cell transplantation (AHCT) may benefit from a combined regimen of plinabulin and pegfilgrastim (Neulasta), according to data from a phase 2 trial (NCT05130827) presented during the 19th International Myeloma Society Annual Meeting.1
At a median follow-up of 3.4 months (range, 2.9-6.7), 10 patients were enrolled to the trial. The median white blood counts on days 0, 1, and 2 was 7.6 × 109 cells/L (range-3.6-9.8), 5 × 109 cells (range, 3.6-9.8), and 18.7 × 109 cells (range, 5.1-59.1), respectively.
Of the 8 patients who have engrafted, the median time to absolute neutrophil count (ANC) of greater than 0.5 × 109 cells/L was 11 days (range, 10-16). The median number of days of ANC less than 0.1 × 109 cells/L was 2 (range, 1-3); the median number of days of ANC less than 0.5 was 5 × 109 cells/L (range, 4-9) days.
A total of 6 patients had fever at a median of 8 days following AHCT (range, 9-12). Moreover, 5 patients with engraftment syndrome received steroids. One 1 patient had non-engraftment–related neutropenic fever; this compares favorably with the historical number of 60% observed with standard of care.
“With symptom burden during AHCT peaking at the time of white blood cell nadir, it’s important to identify strategies that can help reduce the burden of neutropenia,” Gunjan L. Shah, MD, hematologist oncologist and principal investigator of the study at Memorial Sloan Kettering Cancer Center, stated in a press release.2 “The preliminary observation from this pilot trial is that adding plinabulin to prophylactic pegfilgrastim and antibiotics helped to prevent the occurrence of non-engraftment–related febrile neutropenia, which has the potential to be clinically meaningful and also beneficial from a health economics perspective.”
The open-label, investigator-initiated study enrolled patients with histologic confirmation of multiple myeloma who were undergoing AHCT with melphalan at 140 mg/m2 or 200 mg/m2 who were between the ages of 18 years and 75 years, and a Karnofsky performance status of greater than or equal to 60 within 2 weeks before enrollment.3
Participants received a single dose of melphalan and underwent AHCT. They then received plinabulin at a fixed dose of 40 mg. On day +1, pegfilgrastim was given at 6 mg in accordance with standard of care.
The primary end point of the trial was to reduce the period of absolute neutropenia. Other objectives included safety, tolerability, neutrophil and platelet engraftment rate, disease response, progression-free survival, overall survival, and patient-reported outcome (PRO) assessment of symptom burden.
The median age of patients was 64 years (range, 58-74), and 40% were female. Additionally, 40% of patients had stage I disease per International Staging System criteria; 40% had stage II disease, 20% had stage III disease, and 20% had unknown status. Seventy percent of patients were high-risk per fluorescence in situ hybridization, and 30% underwent outpatient HCT.
All participants required platelet transfusions (median 3; range, 1-11), and 3 patients required packed red blood cell transfusions (1-3 units). At day 100, 6 experienced very good partial responses, 2 patients were minimal residual disease (MRD) positive and had a complete response (CR), 2 patients were MRD negative and had a CR.
No patients experienced disease progression and no deaths occurred. Half of patients had hypertension right after they were infused with plinabulin, which is a common toxicity; the effect resolved within a few hours.
PRO data were collected and will be examined. Enrollment is ongoing.