Seroconversion and outcomes after initial and booster COVID-19 vaccination in adults with hematologic malignancies.

BACKGROUND: Patients with hematologic malignancies have impaired humoral immunity secondary to their malignancy and its treatment, placing them at risk of severe coronavirus disease-19 (COVID-19) infection and reduced response to vaccination. METHODS: The authors retrospectively analyzed serologic responses to initial and booster COVID-19 vaccination in 378 patients with hematologic malignancy and subsequently tracked COVID-19-related outcomes. RESULTS: Seroconversion occurred in 181 patients (48%) after initial vaccination; patients who had active malignancy or those who were recently treated with a B-cell-depleting monoclonal antibody had the lowest rates of seroconversion. For initial nonresponders to vaccination, seroconversion after a booster dose occurred in 48 of 85 patients (56%). The seroconversion rate after the booster was similar for patients on (53%) and off (58%) active therapy (p = .82). Thirty-three patients (8.8%) developed a COVID-19 infection, and there were three COVID-19-related deaths (0.8%). Although no significant association was observed between postvaccination seroconversion and the incidence of COVID-19 infection, no patient with seroconversion died from COVID-19, and no patient who received tixagevimab/cilgavimab (N = 25) was diagnosed with a COVID-19 infection. CONCLUSIONS: Booster vaccinations can promote seroconversion in a significant proportion of patients who are seronegative after the initial vaccination course regardless of the specific vaccine or on/off treatment status at the time of revaccination. Although postvaccination seroconversion may not be associated with a decrease in any (including asymptomatic) COVID-19 infection, the authors' experience suggested that effective vaccination (including a booster), supplemented by passive immunization using tixagevimab/cilgavimab in case of lack of seroconversion, effectively eliminated the risk of COVID-19 death in the otherwise high-risk population. LAY SUMMARY: Patients with hematologic malignancy, especially lymphoma, have an impaired response to coronavirus disease 2019 (COVID-19) vaccination. In this single-institution review, less than one half of the patients studied made detectable antibodies. For those who did not make detectable antibodies after initial vaccination, over one half (65%) were able to produce antibodies after booster vaccination. By the end of February 2022, 33 of the original 378 patients had a documented COVID-19 infection. The only deaths from COVID-19 were in those who had undetectable antibodies, and no patient who received prophylactic antibody therapy developed a COVID-19 infection.

Vincristine Sulfate Liposome Injection with Bendamustine and Rituximab as First-Line Therapy for B-Cell Lymphomas: A Phase I Study.

BACKGROUND: We conducted an investigator-initiated, phase I trial of vincristine sulfate liposomal injection (VSLI) in combination with bendamustine and rituximab (BR) for indolent B-cell (BCL) or mantle cell lymphoma. METHODS: Participants received 6 cycles of standard BR with VSLI at patient-specific dose determined by the Escalation with Overdose Control (EWOC) model targeting 33% probability of dose-limiting toxicity (DLT). Maximum tolerated dose (MTD) was the primary endpoint; secondary endpoints included rates of adverse events (AEs), overall response rate (ORR), and complete response (CR). Vincristine sulfate liposomal injection is FDA approved for the treatment of patients with recurrent Philadelphia chromosome-negative (Ph-) acute lymphoblastic leukemia (ALL). RESULTS: Among 10 enrolled patients, VSLI was escalated from 1.80 to 2.24 mg/m2, with one DLT (ileus) at 2.04 mg/m2. Two patients discontinued VSLI early. The most common AE included lymphopenia (100%), constipation, nausea, infusion reaction (each 60%), neutropenia, and peripheral neuropathy (50%). Grade 3/4 AE included lymphopenia (90%), neutropenia (20%), and ileus (10%), with prolonged grade ≥2 lymphopenia observed in most patients. Calculated MTD for VSLI was 2.25 mg/m2 (95% Bayesian credible interval: 2.00-2.40). Overall response was 100% with 50% CR. With median follow-up 26 months, 4/10 patients experienced recurrence and 1 died. CONCLUSION: Vincristine sulfate liposomal injection at 2.25 mg/m2 can be safely combined with BR for indolent B-cell lymphoma, but given observed toxicities and recurrences, we did not pursue an expanded cohort.Clinical Trials Registration Number: ClinicalTrials.gov identifier NCT02257242.