Positive Results from ReiThera’s Phase 1 Trial with COVID-19 Vaccine Candidate GRAd-COV2 Published in Science Translational Medicine

ROME, Italy, October 29th, 2021 – ReiThera Srl, a biotech company dedicated to the technology development, GMP manufacturing and clinical translation of genetic vaccines and medicinal products for advanced therapies, announces that safety and immunogenicity interim data from its Phase 1 dose-escalation trial with GRAd-COV2, its novel gorilla adenovirus-based COVID-19 vaccine candidate, have been published online in the prestigious peer-reviewed journal Science Translational Medicine (Lanini, S. et al). To read the full study click here.

The open-label study assessed the safety and immunogenicity of a single-dose regimen of GRAd-COV2 in healthy younger and older adults to select the appropriate dose for each age group for subsequent clinical development. The trial was conducted in 90 participants (45 people aged 18-55 years and 45 people aged 65-85 years), who received a single intramuscular administration of GRAd-COV2 at three escalating doses.

Four weeks after vaccination, seroconversion to spike protein and receptor binding domain was achieved in 43 of 44 young volunteers and in 45 of 45 older participants. Neutralizing antibodies were detected in 42 of 44 younger age and 45 of 45 older age volunteers. In addition, GRAd-COV2 induced a robust and Th1-skewed T cell response against the spike protein in 89 of 90 participants from both age groups. Local and systemic adverse reactions were mostly mild or moderate and of short duration, and no serious adverse events were reported. Overall, the safety and immunogenicity data from the Phase 1 trial support further development of this vaccine.

The study was conducted by ReiThera in collaboration with the National Institute of Infectious Diseases Lazzaro Spallanzani and was funded by the Lazio Region and the Italian Ministry of University and Research.



Lanini, S. et al. GRAd-COV2, a gorilla adenovirus-based candidate vaccine against COVID-19, is safe and immunogenic in younger and older adults (2021) Science Translational Medicine, DOI: 10.1126/scitranslmed.abj1996 


About GRAd-COV2

GRAd-COV2, the candidate vaccine against SARS-CoV-2 recently developed by ReiThera, is based on a novel and proprietary replication-defective simian (gorilla) adenoviral vector (called GRAd) encoding the full-length coronavirus spike protein (GRAd-COV2). The spike protein enables the coronavirus to enter human cells.

Recent Phase 1 and 2 studies have demonstrated that GRAd-COV2 is safe and well-tolerated in adults and elderly, as well as in subjects with comorbidities, with seroconversion rates over 93% after a single dose and over 99% with a two-dose regimen.

ReiThera’s novel GRAd vector belongs to species C adenovirus that are considered the most potent vaccine carriers and has low seroprevalence in humans. This means that GRAd vaccine immunogenicity is not hampered by pre-existing anti-human adenovirus antibodies.


About ReiThera Srl

ReiThera Srl is a biotech company dedicated to the technology development, GMP manufacturing and clinical translation of genetic vaccines and medicinal products for advanced therapies. The company’s management and scientific teams have developed a highly innovative technological platform based on simian adeno-vectored vaccines against several infectious diseases, such as RSV and Ebola.

ReiThera is led by an experienced management team that has worked together for many years in previous successful enterprises, including Okairos (acquired by GSK), and has a long-standing expertise in scalable processes for viral vector manufacturing, supported by a cGMP facility inclusive of filling suite and quality control laboratories.

ReiThera has its headquarters, R&D laboratories and GMP facilities in Rome, Italy.

For further information see: www.reithera.com


Media Contacts:

ReiThera Srl

Antonella Folgori, Chief Executive Officer


MEDiSTRAVA Consulting – International Press

Sylvie Berrebi, Mark Swallow PhD
+44 (0) 7714306525 / +44 (0) 7903737703


Comin & Partners – Italian Press

Giorgia Bazurli

+39 349 2840676