Curevo Presents Positive Shingles Vaccine Outcomes Data

Curevo Vaccine recently announced an upcoming oral presentation at the World Vaccine Congress  in Barcelona of shingles case outcomes data from an 876-patient Phase 2 trial of amezosvatein (a non-mRNA, adjuvanted subunit vaccine also known as CRV-101) head-to-head versus Shingrix in participants aged 50 years and older.

There were zero confirmed cases of herpes zoster (shingles) in the amezosvatein arm of participants, regardless of dose, after mean follow-up of 18.8 months in this post-hoc analysis of the Phase 2 trial. Based on the shingles incidence rate from the placebo arm North American cohort of ZOSTER-006, a Phase 3 trial of Shingrix, 10 of the 876 participants in the Phase 2 trial should have been diagnosed with a confirmed shingles case absent effective vaccination.¹ There were also no shingles cases in the Shingrix arm of this Phase 2 trial.

“With the duration of follow-up in our Phase 2 trial now sufficient for comparison, we are excited to report zero shingles cases for amezosvatein,” said Dr. Guy De La Rosa, Curevo’s Chief Medical Officer. “These data provide outcomes-based confirmation of the non-inferiority immunogenicity data we reported earlier.”

“These data support our efforts to bring a new shingles vaccine to global markets,” added George Simeon, Curevo’s Chief Executive Officer. “Though somewhat unsurprising, given amezosvatein also showed non-inferior immunogenicity to Shingrix at day 84 in this trial, these longer-term data represent additional de-risking for the program.”

The Phase 2 trial (NCT05304351) enrolled 876 participants to receive either amezosvatein or Shingrix on an identical two-dose, two months apart schedule. 876 participants were randomized to receive one of four different amezosvatein doses or Shingrix. The mean follow-up of the 619 participants receiving amezosvatein was 18.8 months. Mean follow-up of the 257 participants who received Shingrix was 21.5 months. The co-primary endpoint of the Phase 2 trial was anti-gE antibody humoral immune responses one month after the second vaccine dose (Day 84). The randomized, observer-blind, and active-controlled trial was conducted at multiple centers in the USA. All suspected cases of shingles were confirmed by either PCR test or, if PCR testing was inconclusive or unavailable, by a blinded panel of shingles experts – a system similar to one used in multiple prior shingles vaccine pivotal studies.

As presented earlier at the IDWeek scientific conference, this co-primary immunogenicity endpoint was met in the highest amezosvatein dose studied (100 μg gE plus 15 μg SLA-SE) as participants’ immune responses to amezosvatein were non-inferior to participants’ immune responses to Shingrix. High-dose amezosvatein and Shingrix generated similar serum neutralizing antibodies to the varicella zoster virus (VZV) and T-cell responses specific for the gE antigen.

Vaccines are studied for both safety and reactogenicity/tolerability. Data on the reactogenicity/tolerability of amezosvatein and Shingrix were collected via a participant diary filled out for the seven days after each injection. Participants were asked to grade the tolerability of each vaccine on a scale of Grade 1 to Grade 3. Grade 1 represents what are considered normal reactions to an active vaccine that do not interfere or prevent daily activity. Grade 2 represents reactogenicity events interfering with daily activities. Grade 3 represents reactogenicity events preventing daily activities.

Amezosvatein and Shingrix demonstrated comparable safety in this Phase 2 trial. However, the highest dose of amezosvatein demonstrated a clinically-meaningful and statistically-significant improvement for Grade 2 and Grade 3 reactogenicity versus Shingrix.

Just 7.3% of participants in the trial receiving the highest dose of amezosvatein reported a Grade 2 (interferes with daily activity) or Grade 3 (prevents daily activity) reactogenicity event compared to 33.3% of participants receiving Shingrix. This result was statistically significant (p<0.001 in a post hoc analysis unadjusted for multiple comparisons).

Reactogenicity events were broken down between local reactions (injection site pain, redness, or swelling) and systemic reactions (fever, headache, fatigue, myalgia/muscle pain, chills). Just 3.6% of high-dose amezosvatein participants had a Grade 2 or Grade 3 local reactogenicity event compared to 25.3% of Shingrix participants. For systemic reactogenicity events, 5.5% of high-dose amezosvatein participants had a Grade 2 or Grade 3 event versus 19.1% for Shingrix. Both results were statistically significant (p=0.0002 and p=0.0139, respectively, in a post hoc analysis unadjusted for multiple comparisons). No Grade 3 reactogenicity events were reported for amezosvatein.

‘Amezosvatein’ is the assigned non-proprietary name for CRV-101, a non-mRNA adjuvanted subunit vaccine under investigation by Curevo. Like Shingrix, amezosvatein uses a subunit protein antigen called glycoprotein ‘E’ (gE). Targeting the gE antigen is proven to elicit a long-term, protective immune response to prevent shingles. Also like Shingrix, amezosvatein uses an adjuvant targeting the TLR4 pathway to boost the immune response to the gE antigen. Amezosvatein was engineered to have a best-in-class safety profile in addition to manufacturing advantages to improve vaccine accessibility. The SLA-SE adjuvant formulation was developed at Seattle-based Access to Advanced Health Institute (AAHI) and amezosvatein was licensed from the Mogam Institute for Biomedical Research, a research institute funded by South Korea’s GC Biopharma.

Also called ‘herpes zoster’, shingles occurs when the varicella zoster virus causing childhood chickenpox re-emerges from sensory ganglion nervous system cells where the virus lies dormant after initial exposure. Virtually all adults have been exposed to the varicella zoster virus and around 30% will develop shingles at least once in their lifetime. The blistering skin rash accompanying shingles also causes severe pain, with both pain and rash lasting up to four weeks. Between 10%-18% of those who get shingles develop post-herpetic neuralgia (PHN), a condition marked by debilitating nerve pain lasting over six months and often beyond one year. There is no approved treatment for PHN. Shingles may also affect the eyes, potentially causing loss of vision. Contracting shingles has also been linked with increased risk of heart attack, stroke, and dementia/Alzheimer’s disease.

Curevo is a privately held, clinical-stage biotechnology company based near Seattle dedicated to reducing the burden of infectious disease by developing vaccines with improved tolerability and accessibility. Curevo’s lead product is amezosvatein, a non-mRNA sub-unit vaccine to prevent shingles, a serious medical condition involving a painful, blistering skin rash where 10-18% of people also develop serious, long-lasting nerve pain. The current $4+ billion shingles vaccine market is characterized by accessibility issues and vaccine hesitancy/dose avoidance related to vaccine tolerability. Curevo is also developing a non-live, non-mRNA subunit chickenpox vaccine intended to reduce or eliminate barriers to immunizing immunocompromised children. For more information, visit https://curevovaccine.com/.