(Reuters) – (This is an excerpt of the Health Rounds newsletter, where we present latest medical studies on Tuesdays and Thursdays)
The first human clinical trials testing a new strategy to protect against HIV infections have yielded promising early results, according to two separate reports published on Thursday in Science.
The trials tested “germline targeting” HIV vaccines, which aim to activate immune system B cells in their naive, or germline, state, inducing them to become specialized cells that produce broadly neutralizing antibodies (bnAbs).
By delivering a variety of HIV immunogens – typically, viral protein fragments – germline vaccines train the B cells to produce antibodies that can recognize and block a broad range of different strains of HIV from infecting healthy cells.
Germline targeting requires an initial dose to prime the correct B cells, and subsequent doses to guide their maturation until they can produce effective bnAbs, the researchers reported.
“Across the participants we saw an immune response that indicates that we’re on the right track,” Rogier Sanders of Amsterdam UMC, senior investigator on one of the trials, said in a statement.
“We saw that we can target the cells that we need to target with atomic precision. The next step is to further stimulate these cells to secrete broadly neutralizing antibodies,” Sanders said.
In a separate paper, a different team of researchers reported on two early trials that used mRNA-encoded nanoparticles produced by Moderna to successfully prime the germline B cells, although a small proportion of patients had skin reactions to the vaccines.
The mRNA technology, similar to that used in Moderna’s COVID-19 shots, would allow for faster vaccine development, the study authors said.
One of the trials was conducted in the United States and the other in Rwanda and South Africa. The majority of HIV patients live in Africa, but germline targeting has not previously been attempted there.
The researchers said the mRNA approach appeared to work with both North American and African populations, opening the door to further testing of germline-targeting vaccines for “African populations in most need of an HIV vaccine.”
EASING THERAPIES FOR SOME PROSTATE, CERVIX CANCERS
Two new studies suggest that patients with certain cancers might do just as well with a shorter course of radiation or a less extensive surgery as with standard treatments.
In JAMA Oncology, researchers reported that in men who require radiation after undergoing the most extensive type of surgery for prostate cancer, a form of high-dose radiation delivered in just five sessions known as stereotactic body radiotherapy (SBRT) appears to be as safe as conventional treatment delivered daily for up to seven weeks.
SBRT is a well-established treatment for prostate cancer, but its use after a radical prostatectomy has been limited due to concerns about the shifting position of the prostate bed and nearby healthy tissues.
The researchers tracked 100 men treated with SBRT in the single-arm study. Two years after the treatment, outcomes and side effects were similar to what the researchers had seen in the past from patients who received the longer-course treatments.
If randomized studies and longer follow-up confirm the results, “this approach could remove a major barrier to post-surgery radiation therapy,” study leader Dr. Amar Kishan of the David Geffen School of Medicine at UCLA said in a statement.
In JAMA Network Open, a separate team of researchers reported that women with low-risk early-stage cancer of the cervix do as well after simple hysterectomy as after modified radical hysterectomy or radical hysterectomy.
Among 2,636 carefully selected patients treated for stage IA2 or IB1 cervical carcinoma at accredited cancer hospitals, there was no difference in survival rates at 3 years, 5 years, 7 years or 10, or in postoperative outcomes after the three types of surgery.
(Reporting by Nancy Lapid; Editing by Bill Berkrot)
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