Strong T-cell response for blood cancer patients after vaccine; COVID breakthrough often serious for cancer patients

Reuters

11:48 JST, June 7, 2022

The following is a summary of some recent studies on COVID-19 and cancer presented at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago.

Blood cancer patients show strong T-cell response to COVID vaccines

Patients with blood cancers have a significantly weaker antibody response to COVID-19 vaccines than patients with solid tumors, but they may still be well protected against severe illness from the virus, new data suggests https://meetings.asco.org/abstracts-presentations/207007.

Researchers at Monash University in Australia studied immune responses after three doses of the COVID vaccines from Moderna , Pfizer/BioNTech or AstraZeneca in nearly 400 adults with active or recently treated cancers. Only 3.2% of the 256 patients with solid tumors lacked antibodies capable of neutralizing SARS-CoV-2 and preventing infection, compared to 30% of the 137 with hematological malignancies, researchers reported on Saturday at ASCO 2022. But responses of immune cells called T cells, some of which can kill cells infected with the virus, were similar regardless of cancer type. T cell responses, therefore, may indicate immune protection “for those without antibody response,” the researchers said.

The same team reported in a separate presentation https://meetings.asco.org/abstracts-presentations/207006 on Saturday that data on the safety of COVID-19 vaccines for cancer patients “are reassuring.” Survey responses from nearly 500 adults and children showed most experienced some after-effects, with pain at the injection site and fatigue most common. But severe reaction rates were low (ranging from 0%-10%) and interruptions to cancer treatment were uncommon (0%-11%). “No significant change in quality of life was reported for dose 1 or 2 in children or adults,” the researchers said.

Breakthrough COVID-19 in cancer patients is often serious

A large proportion of vaccinated cancer patients who develop breakthrough COVID-19 require hospitalization, according to data collected by the American Society of Clinical Oncology and reported at ASCO 2022 https://meetings.asco.org/abstracts-presentations/206639.

Researchers studied 231 patients who had breakthrough infections while receiving treatment for cancer or within a year of treatment. The patients had received at least one dose of a vaccine from Pfizer/BioNTech, Moderna or Johnson & Johnson . Most of the breakthrough cases occurred more than six months later. Among patients with non-metastatic solid tumors and breakthrough infections, nearly 20% were hospitalized. Hospitalization rates for blood cancer patients with breakthrough COVID-19 ranged from 32% to 56%.

“While the fraction of patients in the ASCO registry with breakthrough cases who were hospitalized remained fairly constant throughout 2021 (about 40%), those with breakthrough cases occurring in the last month of 2021 and early 2022 had a lower hospitalization rate (at about 20%), which is consistent with less severe cases of COVID-19 in patients infected with the Omicron variant,” the researchers said in a summary of their presentation. “A majority of SARS-CoV-2 infections occurring six months or more after vaccination suggests waning vaccine efficacy over time that could be impacted by additional doses,” they said.

Cancer patients over-represented in long COVID group

Cancer patients account for an outsized proportion of people who end up with persistent, troublesome symptoms after recovering from COVID-19, a condition known as long COVID, U.S. researchers reported on Saturday at ASCO 2022 https://meetings.asco.org/abstracts-presentations/212380.

From a nationally representative sample of over 4.3 million people diagnosed with COVID-19 between January 2020 and February 2022, they identified 1,700 adults with long COVID and found that 37.3% were cancer patients. The most common cancers were skin (seen in 21.9% of the cancer patients), breast (17.7%), prostate (8.3%), lymphoma (8%) and leukemia (5.7%).

Among long COVID patients, those with cancer were older than non-cancer patients, more likely to have other medical conditions, and more likely to have been hospitalized for COVID-19. The researchers call for “further investigation to identify risk factors for long COVID in patients with cancer.”