antibodies

Study shows that COVID-19 vaccine is safe and effective in people with cancer

/ Yimy Villa / Leave a comment

As we have seen in the US and all around the world, SARS-CoV-2, the virus that causes COVID-19, can cause severe complications and even death in many patients. In the early days of the pandemic, CIRM authorized $5 million in emergency funding for projects targeting the virus. To date CIRM has funded 20 projects related to COVID-19 research, including three clinical studies.

Luckily there have been several vaccines developed that are extremely effective at protecting individuals from the virus. These vaccines work by priming the body’s immune system to produce antibodies that are able to recognize and destroy SARS-CoV-2.

However, one question that remains is if patients with a weakened immune system, such as those receiving active cancer treatment, would be able to produce the antibodies after vaccination. Fortunately, a review of 200 patients with a wide spectrum of cancer diagnoses conducted by researchers at Montefiore Health System and Albert Einstein College of Medicine in the Bronx, NY, found that the COVID-19 vaccine is safe and effective in people with cancer.

The study looked at the rate of seroconversion, which indicates the presence of SARS-CoV-2 antibodies, in patients with solid tumors and blood cancers. The higher the rate of seroconversion, the more protection from COVID the patient has. The results showed that overall 94 percent of patients demonstrated seroconversion. Patients with solid tumors had a higher seroconversion rate compared to patients with blood cancers. Among patients with solid tumors 98 percent showed seroconversion while those with blood cancers showed a seroconversion rate of 85 percent.

The seroconversion rate also varied between those that received different cancer treatments. Those that received therapies for blood cancers that work by killing B cells (such as rituximab or CAR-T therapies) showed seroconversion rates of 70 percent. For those who had recently had bone marrow or stem cell transplants, the success rate was 74 percent. But the researchers stated that those rates were still much higher than expected.

In a news release, Amit Verma, M.B.B.S., senior co-author on the study, stresses the importance of cancer patients getting vaccinated.

“Vaccination among these populations have been lower, even though these groups were hardest hit by the pandemic. It’s important to stress how well these patient populations did with the vaccines.”

The full results of the study were published in Cancer Cell.

CIRM Board Funds its First Clinical Study for COVID-19

/ Yimy Villa / 1 Comment
Dr. John Zaia, City of hope

Today the governing Board of the California Institute for Regenerative Medicine (CIRM) continued its commitment to help with the coronavirus pandemic by awarding $749,999 to Dr. John Zaia at City of Hope.  He will be conducting a clinical study to administer blood plasma from recovered COVID-19 patients to treat those with the virus.  This marks CIRM’s first clinical study for COVID-19 after approving emergency funding a month earlier.

Plasma is a component of blood that carries proteins called antibodies that are usually involved in defending our bodies against viral infections.  Blood plasma from patients that have recovered from COVID-19, referred to as convalescent plasma, contain antibodies against the virus that can be used as a potential treatment for COVID-19.  Currently, there are challenges with this approach that include: properly identifying convalescent plasma donors i.e. recovered patients, determining eligibility of those with convalescent plasma that want to donate, collection of the plasma, treating patients, and determining if the plasma was effective.

Dr. Zaia and his team at City of Hope will create the COVID-19 Coordination Program, which addresses solutions for all of the challenges listed above. The program will partner with the medical teams at CIRM’s Alpha Stem Cell Clinic Network, as well as infectious disease, pulmonary and critical care teams from medical centers and community hospitals across the state.  Potential donors will be identified and thoroughly screened for eligibility per the established National and State blood banking safety requirements. Finally, the convalescent plasma will be collected from eligible donors and administered by licensed physicians to COVID-19 patients, who will be evaluated for response to the treatment and potential recovery.

“We are in the midst of very challenging times where there is not yet an approved treatment for COVID-19. In response to this, CIRM launched and executed an emergency COVID-19 funding program, which was made possible by our Board, patient advocates, California scientists, external scientific expert reviewers, and our dedicated team,” said Maria T. Millan, MD, President and CEO of CIRM. “With CIRM funding, the City of Hope COVID-19 Coordination program will tap into CIRM’s network of researchers, physicians, and our Alpha Clinics to deliver this treatment to patients in need.  It will also serve the critical role of gathering important scientific data about the plasma, safety, and clinical data from treated patients.”

The Board also approved a discovery stage research project that utilizes stem cell models for a novel approach to vaccine development against the virus causing COVID-19 and another project that uses a unique lung stem cell organoid to identify an effective drug against the virus.

The two awards are summarized in the table below:

Stanford study successful in transplant of mismatched stem cells, tissue in mice

/ Yimy Villa / 1 Comment
Dr. Irv Weissman at Stanford University

A transplant can be a lifesaving procedure for many people across the United States. In fact, according to the Health Resources & Services Administration, 36,528 transplants were performed in 2018. However, as of January 2019, the number of men, women, and children on the national transplant waiting list is over 113,000, with 20 people dying each day waiting for a transplant and a new person being added to the list every 10 minutes.

Before considering a transplant, there needs to be an immunological match between the donated tissue and/or blood stem cells and the recipient. To put it simply, a “match” indicates that the donor’s cells will not be marked by the recipient’s immune cells as foreign and begin to attack it, a process known as graft-versus-host disease. Unfortunately, these matches can be challenging to find, particularly for some ethnic minorities. Often times, immunosuppression drugs are also needed in order to prevent the foreign cells from being attacked by the body’s immune system. Additionally, chemotherapy and radiation are often needed as well.

Fortunately, a CIRM-funded study at Stanford has shown some promising results towards addressing the issue of matching donor cells and recipient. Dr. Irv Weissman and his colleagues at Stanford have found a way to prepare mice for a transplant of blood stem cells, even when donor and recipient are an immunological mismatch. Their method involved using a combination of six specific antibodies and does not require ongoing immunosuppression.

The combination of antibodies did this by eliminating several types of immune cells in the animals’ bone marrow, which allowed blood stem cells to engraft and begin producing blood and immune cells without the need for continued immunosuppression. The blood stem cells used were haploidentical, which, to put it simply, is what naturally occurs between parent and child, or between about half of all siblings. 

Additional experiments also showed that the mice treated with the six antibodies could also accept completely mismatched purified blood stem cells, such as those that might be obtained from an embryonic stem cell line. 

The results established in this mouse model could one day lay the foundation necessary to utilize this approach in humans after conducting clinical trials. The idea would be that a patient that needs a transplanted organ could first undergo a safe, gentle transplant with blood stem cells derived in the laboratory from embryonic stem cells. The same embryonic stem cells could also then be used to generate an organ that would be fully accepted by the recipient without requiring the need for long-term treatment with drugs to suppress the immune system. 

In a news release, Dr. Weissman is quoted as saying,

“With support by the California Institute for Regenerative Medicine, we’ve been able to make important advances in human embryonic stem cell research. In the past, these stem cell transplants have required a complete match to avoid rejection and reduce the chance of graft-versus-host disease. But in a family with four siblings the odds of having a sibling who matches the patient this closely are only one in four. Now we’ve shown in mice that a ‘half match,’ which occurs between parents and children or in two of every four siblings, works without the need for radiation, chemotherapy or ongoing immunosuppression. This may open up the possibility of transplant for nearly everyone who needs it. Additionally, the immune tolerance we’re able to induce should in the future allow the co-transplantation of [blood] stem cells and tissues, such as insulin-producing cells or even organs generated from the same embryonic stem cell line.”

The full results to this study were published in Cell Stem Cell.