Safety and immunogenicity of heterologous COVID-19 vaccine regimens to deal with product shortage: A randomised clinical trial in an elderly population

Objectives

In a context of COVID-19 vaccine shortages, this study sought to evaluate the safety and efficacy of receiving one dose of Gam-COVID-Vac rAd26 followed by a second COVID-19 vaccine dose of either Gam-COVID-Vac rAd5, ChAdOx1 nCoV-19 or BBIBP-CorV in a cohort of older adults.

Study design

Single-centre, randomised, open label, non-inferiority trial.

Methods

Adults aged ≥65 years who had received one dose of Gam-COVID-Vac rAd26 were randomised in a 1:1:1 ratio to receive a second-dose COVID-19 vaccination of either Gam-COVID-Vac rAd5, ChAdOx1 nCoV-19 or BBIBP-CorV. The primary outcome was the assessment of the humoral immune response to vaccination (i.e. antibody titres of SARS-CoV-2 spike protein at 28 days after second-dose vaccination). In addition, neutralising antibody titres at day 28 for the three schedules were measured.

Results

Of 85 participants who were enrolled in the study between 26 and July 30, 2021, 31 individuals were randomised to receive Gam-COVID-Vac rAd5, 27 to ChAdOx1 nCoV-19 and 27 to BBIBP-CorV. The mean age of participants was 68.2 years (SD 2.9) and 49 (57.6%) were female. Participants who received Gam-COVID-Vac rAd5 and ChAdOx1 nCoV1-19 showed significantly increased anti-S titres at 28 days after second-dose vaccination, but this magnitude of difference was not observed for those who received BBIBP-CorV. The ratio between the geometric mean at day 28 and baseline within each group was 11.8 (6.98-19.89) among patients assigned to Gam-COVID-Vac rAd26/rAd5, 4.81 (2.14-10.81) for the rAd26/ChAdOx1 nCoV-19 group and 1.53 (0.74-3.20) for the rAd26/BBIBP-CorV group. All of the schedules were shown to be safe.

Conclusions

The findings in this study contribute to the scarce information published on the safety and immunogenicity of Gam-COVID-Vac heterologous regimens and will help the development of guidelines and vaccine programme management.

A Randomized Trial to Evaluate Lopinavir/Ritonavir versus Saquinavir/Ritonavir in HIV-1-Infected Patients: The Maxcmin2 Trial

Objective

To assess the rate of protocol-defined treatment failure and safety of lopinavir/ritonavir (LPV/r) and saquinavir/ritonavir (SAQ/r).

Design

Open-label, prospective, randomized (1:1), international multi-centre trial.

Methods

Adult HIV-1-infected patients were assigned LPV/r 400/100 mg twice daily or SAQ/r 1000/100 mg twice daily with two or more nucleoside reverse transcriptase inhibitors (NRTIs)/non-NRTIs. All patients, whether on or off the assigned treatment, were followed for 48 weeks.

Results

Of 339 randomized patients, 324 initiated assigned treatment (intention-to-treat/exposed [ITT/e] population). At 48 weeks, treatment failure occurred in 29/163 (18%) and 53/161 (33%) of patients in the LPV/r and SAQ/r arms, respectively (ITT/e, P=0.002, log rank test). In an analysis that also considered those patients who discontinued treatment as having failed treatment (ITT/e/discontinuation=failure), 40/161 (25%) LPV/r-treated individuals versus 63/161 (39%) SAQ/R-treated individuals failed treatment ( P=0.005, log rank test). Discontinuation of the assigned treatment occurred in 23/163 (14%) patients in the LPV/r-treated group, compared with 48/161 (30%) in the SAQ/r-treated group (ITT/e; P=0.001). The primary reasons for premature discontinuation were non-fatal adverse events (LPV/r: 12/163; SAQ/r: 21/161) and patients’ choice (LPV/r: 7/163; SAQ/r: 8/161). In the on-treatment analysis of time to treatment failure, no difference was observed between the two arms ( P=0.27, log rank test).

Conclusion

LPV/r had better antiretroviral effects compared with SAQ/r at the doses and in the formulations studied. This may have been a result of patients’ preferences and ability to adhere to assigned therapy, rather than a result of differences in the intrinsic potency of the study protease inhibitors.