Safety and immunogenicity of Nanocovax, a SARS-CoV-2 recombinant spike protein vaccine: Interim results of a double-blind, randomised controlled phase 1 and 2 trial

BACKGROUND

Nanocovax is a recombinant severe acute respiratory syndrome coronavirus 2 subunit vaccine composed of full-length prefusion stabilized recombinant SARS-CoV-2 spike glycoproteins (S-2P) and aluminium hydroxide adjuvant.

METHODS

We conducted a dose-escalation, open label trial (phase 1) and a randomized, double-blind, placebo-controlled trial (phase 2) to evaluate the safety and immunogenicity of the Nanocovax vaccine (in 25 mcg, 50 mcg, and 75 mcg doses, aluminium hydroxide adjuvanted (0·5 mg/dose) in 2-dose regime, 28 days apart (ClinicalTrials.gov number, NCT04683484). In phase 1, 60 participants received two intramuscular injection of the vaccine following dose-escalation procedure. The primary outcomes were reactogenicity and laboratory tests to evaluate the vaccine safety. In phase 2, 560 healthy adults received either vaccine doses similar in phase 1 (25 or 50 or 75 mcg S antigen in 0·5 mg aluminium per dose) or adjuvant (0·5 mg aluminium) in a ratio of 2:2:2:1. One primary outcome was the vaccine safety, including solicited adverse events for 7 day and unsolicited adverse events for 28 days after each injection as well as serious adverse event or adverse events of special interest throughout the study period. Another primary outcome was anti-S IgG antibody response (Index unit/ml). Secondary outcomes were surrogate virus neutralisation (inhibition percentage), wild-type SARS-CoV-2 neutralisation (dilution fold), and T-cell responses by intracellular staining for interferon gamma (IFNg). Anti-S IgG and neutralising antibody levels were compared with convalescent serum samples from symptomatic Covid-19 patients.

FINDINGS

For phase 1 study, no serious adverse events were observed for all 60 participants. Most adverse events were grade 1 and disappeared shortly after injection. For phase 2 study, after randomisation, 480 participants were assigned to receive the vaccine with adjuvant, and 80 participants were assigned to receive the placebo (adjuvant only). Reactogenicity was absent or mild in the majority of participants and of short duration (mean ≤3 days). Unsolicited adverse events were mild in most participants. There were no serious adverse events related to Nanocovax. Regarding the immunogenicity, Nanocovax induced robust anti-S antibody responses. In general, there humoral responses were similar among vaccine groups which reached their peaks at day 42 and declined afterward. At day 42, IgG levels of vaccine groups were 60·48 [CI95%: 51·12-71·55], 49·11 [41·26-58·46], 57·18 [48·4-67·5] compared to 7·10 [6·32-13·92] of convalescent samples. IgG levels reported here can be converted to WHO international standard binding antibody unit (BAU/ml) by multiplying them to a conversion factor of 21·8. Neutralising antibody titre of vaccine groups at day 42 were 89·2 [52·2-152·3], 80·0 [50·8-125.9] and 95·1 [63·1-143·6], compared to 55·1 [33·4-91·0] of the convalescent group.

INTERPRETATION

Up to day 90, Nanocovax was found to be safe, well tolerated, and induced robust immune responses.

FUNDING

This work was funded by the Coalition for Epidemic Preparedness Innovations (CEPI), the Ministry of Science and Technology of Vietnam, and Nanogen Pharmaceutical Biotechnology JSC.

High-grade carcinoma of the prostate: a comparison of current local therapies

OBJECTIVES

To determine the impact of either single or combined local therapeutic modalities for poorly differentiated (Gleason score 8 to 10) prostate cancer.

METHODS

Between 1987 and 1996, 156 patients were diagnosed with biopsy proven, poorly differentiated (Gleason score 8 to 10), clinically localized prostate cancer. Of these patients, 87 were treated with radical prostatectomy alone, 19 with radiotherapy, and 24 with both prostatectomy and postoperative radiotherapy.

RESULTS

The median follow-up time was 74.6 months. The 5-year biochemical progression-free survival (PFS) for patients with a Gleason score of 8 to 10 was 65%, 30%, and 20% for patients treated with surgery plus postoperative radiotherapy, radiotherapy alone, and surgery alone, respectively (P <0.0001 between postoperative radiotherapy and all other groups, P = 0.6131 between surgery and radiotherapy). The 5-year clinical PFS was 80%, 60%, and 35% for patients treated with surgery plus postoperative radiotherapy, radiotherapy alone, and surgery alone (P <0.0001 between postoperative radiotherapy and all others, P = 0.1975 between surgery and radiotherapy). The independent prognosticators for biochemical failure included serum prostate-specific antigen level greater than 20 ng/mL and seminal vesicle invasion; only seminal vesicle invasion was prognostic for clinical failure.

CONCLUSIONS

Patients with high-grade prostate cancer (Gleason score 8 to 10) have uniformly poor, but apparently similar, biochemical and clinical PFS rates when treated by either prostatectomy or radiotherapy alone. The addition of postoperative radiotherapy in the treatment of these patients may be associated with improved biochemical and clinical PFS compared with either modality alone.

Pericarditis causing exercise test induced ST-elevations

Pericarditis has not been well associated with exercise test induced ST-elevations. This case report of a pericarditis patient who underwent exercise stress testing and other similar cases found in the literature suggest that this is an unrecognized clinical manifestation of pericarditis.