Two Studies Assess Pfizer’s Effectiveness Against Omicron

The Omicron variant substantially reduced antibody levels generated by the Pfizer-BioNTech COVID-19 vaccine, according to preliminary results from a South African study that’s still awaiting peer review. These are the first laboratory results to see how a COVID-19 vaccine holds up to Omicron. A team of researchers led by Africa Health Research Institute‘s Alex Sigal tested 14 blood samples from 12 people against a live sample of the Omicron variant. All 12 people were vaccinated, and six were previously infected.

Overall, the scientists found a roughly 40-fold reduction in the levels of neutralizing antibodies, the virus-fighting proteins that play a key role in our immune response, compared with the original version of the virus. Omicron did not evade vaccine protection completely, Sigal wrote on Twitter, meaning there’s still benefit to being vaccinated against this new variant. But the marked reduction in antibodies raises questions of how durable vaccine protection will be against Omicron – namely, whether booster shots will sufficiently ward off disease or if new vaccines may eventually be required. Sigal called it a “very large drop in neutralization of Omicron.”

A good booster probably would decrease your chance of infection, especially severe infection leading to more severe disease,” Sigal said in an online presentation of his results on Tuesday, according to Bloomberg. “People who haven’t had a booster should get one, and people who have been previously infected should be vaccinated.”

Shortly after Sigal announced his team’s results, another group of researchers at Sweden‘s Karolinska Institutet disclosed their own findings that suggested a substantial but less dramatic decline in antibody levels. The Karolinska team found a seven-fold reduction across 17 blood samples. They noted the impact of Omicron varied greatly between samples, and they used a version of Omicron that was artificially made in a lab instead of the live virus. A lead researcher for that group said the findings make Omicron “certainly worse than Delta, but, again, not as extreme as we expected.” The results are not finalized and have not been published in a medical journal. Sigal cautioned on Twitter that the findings “are likely to be adjusted as we do more experiments.”

Source: https://www.sciencealert.com/

What Is Regeneron, The Antibody Cocktail Used To Cure Trump?

A descriptive analysis of Regeneron Pharmaceuticals‘ Phase I/II/III clinical trial has found that its antibody cocktail REGN-COV2 lowered viral load and the time to symptoms improvement in non-hospitalised Covid-19 patients. The therapy also demonstrated positive trends in decreasing medical visits. During the ongoing, randomised, double-blind trial, the combination of REGN-COV2 and usual standard-of-care is being compared to placebo plus standard-of-care.

Regeneron noted that trial participants were given a one-time infusion of 8g or 2.4g of REGN-COV2 or placeboData from the descriptive analysis is based on the findings from the initial 275 patients. The analysis evaluated anti-viral activity with the therapy and is intended to detect patients who are most likely to benefit from treatment. Safety analysis revealed that both doses of the therapy were well-tolerated, with infusion reactions found in four patients.

The greatest treatment benefit was in patients who had not mounted their own effective immune response, suggesting that REGN-COV2 could provide a therapeutic substitute for the naturally-occurring immune response, ” said Regeneron Pharmaceuticals president and chief scientific officer George Yancopoulos. “We are highly encouraged by the robust and consistent nature of these initial data, as well as the emerging well-tolerated safety profile, and we have begun discussing our findings with regulatory authorities while continuing our ongoing trials.

This trial is part of a clinical programme, which includes studies of REGN-COV2 to treat hospitalised patients and to prevent infection in people exposed to Covid-19 patients. More than 2,000 subjects have been recruited across the overall REGN-COV2 development programme. At least 1,300 participants will be part of the Phase II/III portion of the outpatient trial overall. In July, Regeneron launched Phase III trials of REGN-COV2 for the treatment and prevention of Covid-19.

Source: https://www.clinicaltrialsarena.com/

Micromotors Deliver Oral Vaccines

Researchers are working on new generations of oral vaccines for infectious diseases. But to be effective, oral vaccines must survive digestion and reach immune cells within the intestinal wall. As a step in this direction, UC San Diego nanoengineering researchers have developed oral vaccines powered by micromotors that target the mucus layer of the intestine.

The work appears in the ACS journal Nano Letters. It’s a collaboration between the labs of nanoengineering professors Joseph Wang and Liangfang Zhang at the UC San Diego Jacobs School of Engineering.

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The lack of needles is one reason oral vaccines are attractive. Another reason: oral vaccines can generate a broad immune response by stimulating immune cells within the mucus layer of the intestine to produce a special class of antibody called immunoglobulin A (IgA). The NanoLetters paper documents the team’s efforts to use magnesium particles as tiny motors to deliver an oral vaccine against the bacterial pathogen Staphylococcus aureus. When coated over most of their surfaces with titanium dioxide, magnesium microparticles use water as fuel to generate hydrogen bubbles that power their propulsion.

To develop the oral vaccine, the researchers coated magnesium micromotors with red blood cell membranes that displayed the Staphylococcal α-toxin, along with a layer of chitosan to help them stick to the intestinal mucus. Then, they added an enteric coating that protects drugs from the acidic conditions of the stomach.

The micromotors safely passed through the stomach to the intestine, at which point the enteric coating dissolved, activating the motors. Imaging of mice that had been given the vaccine showed that the micromotors accumulated in the intestinal wall much better than non-motorized particles. The micromotors also stimulated the production of about ten times more IgA antibodies against the Staphylococcal α-toxin than the static particles.

Source: http://jacobsschool.ucsd.edu/

Antibodies Are The New Cancer Weapon

Antibody-based imaging* of a particularly aggressive form of breast cancer is undergoing clinical trials worldwide, but the path from trial to application is being hampered by a major obstacle: safety. Concerns stem from inefficient tumor targeting, which can result in accumulation in the bone marrow, liver and kidneys of the radioactive material necessary for the imaging. Recent efforts have focused on nanoscale delivery vehicles with immune components, but these vehicles are often still too large (20 nanometers or larger) for renal clearance after imaging.

Ulrich Wiesner, the Spencer T. Olin Professor of Engineering in materials science and engineering, in collaboration with Dr. Michelle Bradbury of Memorial Sloan Kettering Cancer Center (MSKCC) and Weill Cornell Medicine, has proposed a novel approach using ultrasmall silica nanoparticles – better known as “Cornell dots” (or C dots) – invented in his lab more than a dozen years ago. Their team – including researchers at pharmaceutical company MedImmune – have equipped the C dots with antibody fragments. Because the resulting conjugates are smaller than 8 nanometers, these C dots allow for renal clearance while achieving the specificity needed for efficient tumor targeting.

They report their discovery in in Nature Communications. Feng Chen, senior research scientist at MSKCC, and Kai Ma, postdoctoral researcher in the Wiesner lab, are co-lead authors. Wiesner said this research creates “a whole new runway” to employ antibody fragments for a number of diseases, cancer in particular, and for diagnostics as well as drug delivery – when combined in a single entity also known as “theranostics.”

A rendering of the Cornell prime dot (left) with an attached antibody fragment (center) binding to a HER2 cancer cell receptor (right). The dot and antibody attachment combined are less than 8 nanometers in diameter, the limit for renal clearance.

This is the first time we’ve worked with these antibody fragments,” Wiesner said, “thereby harnessing the power of antibodies in the fight against cancer.”

Cancer imaging is an umbrella term that covers the many approaches used to research and diagnose cancer. Originally used to diagnose and stage the disease, cancer imaging is now also used to assist with surgery and radiotherapy, to look for early responses to cancer therapies and to identify patients who are not responding to treatment.

Source: http://news.cornell.edu/