Increased risk for autism appears to be linked to the Y chromosome, a Geisinger study found, offering a new explanation for the greater prevalence of autism in males. The results were published today in Nature Communications.
Autism spectrum disorder (ASD) is nearly four times more prevalent among males than females, but the reason for this disparity is not well understood. One common hypothesis involves the difference in sex chromosomes between males (XY) and females (XX).
“A leading theory in the field is that protective factors of the X chromosome lower autism risk in females,” said Matthew Oetjens, PhD, assistant professor at Geisinger’s Autism & Developmental Medicine Institute.
The Geisinger research team, led by Dr Oetjens and Alexander Berry, PhD, staff scientist, sought to determine the effects of the X and Y chromosomes on autism risk by examining ASD diagnoses in people with an abnormal number of X or Y chromosomes, a genetic condition known as sex chromosome aneuploidy.
The team analysed genetic and ASD diagnosis data on 177 416 patients enrolled in the Simons Foundation Powering Autism Research (SPARK) study and Geisinger’s MyCode Community Health Initiative.
They found that individuals with an additional X chromosome had no change in ASD risk, but that those with an additional Y chromosome were twice as likely to have an ASD diagnosis.
This suggests a risk factor associated with the Y chromosome instead of a protective factor associated with the X chromosome.
“While these may seem like two sides of the same coin, our results encourage us to look for autism risk factors on the Y chromosome instead of limiting our search to protective factors on the X chromosome,” Dr. Berry said.
“However, further research is needed to identify the specific risk factor associated with the Y chromosome.”
This analysis also confirms prior work by showing that the loss of an X or Y chromosome, known as Turner syndrome, is associated with a large increase in ASD risk. Further research is needed to determine whether the ASD risk factors associated with sex chromosome aneuploidy explains the sex difference in ASD prevalence.
Plant fungus provides new drug with a new cellular target
Human colon cancer cells. Credit: National Cancer Institute
Novel chemical compounds from a fungus could provide new perspectives for treating colorectal cancer, one of the most common and deadliest cancers worldwide. The fungus, Bipolaris victoriae, is otherwise known as a fungal plant pathogen which in the 1940s caused the “Victoria blight”, decimating oats and similar grains in the US.
In the journal Angewandte Chemie, researchers reported on the isolation and characterisation of a previously unknown class of metabolites (terpene-nonadride heterodimers). One of these compounds effectively kills colorectal cancer cells by attacking the enzyme DCTPP1, which thus may serve as a potential biomarker for colorectal cancer and a therapeutic target.
Rather than using conventional cytostatic drugs, which have many side effects, modern cancer treatment frequently involves targeted tumour therapies directed at specific target molecules in the tumour cells. The prognosis for colorectal cancer patients remains grim however, demanding new targets and novel drugs.
Targeted tumour therapies are mostly based on small molecules from plants, fungi, bacteria, and marine organisms. About half of current cancer medications were developed from natural substances. A team led by Ninghua Tan, Yi Ma, and Zhe Wang at the China Pharmaceutical University (Nanjing, China) chose to use Bipolaris victoriae S27, a fungus that lives on plants, as the starting point in their search for new drugs.
The team first analysed metabolic products by cultivating the fungus under many different conditions (OSMAC method, one strain, many compounds). They discovered twelve unusual chemical structures belonging to a previously unknown class of compounds: terpene-nonadride heterodimers, molecules made from one terpene and one nonadride unit. Widely found in nature, terpenes are a large group of compounds with very varied carbon frameworks based on isoprene units. Nonadrides are nine-membered carbon rings with maleic anhydride groups. The monomers making up this class of dimers termed “bipoterprides” were also identified and were found to contain additional structural novelties (bicyclic 5/6-nonadrides with carbon rearrangements).
Nine of the bipoterprides were effective against colorectal cancer cells. The most effective was bipoterpride No. 2, which killed tumour cells as effectively as the classic cytostatic drug Cisplatin. In mouse models, it caused tumours to shrink with no toxic side effects.
The team used a variety of methods to analyse the drug’s mechanism: bipoterpride 2 inhibits dCTP-pyrophosphatase 1 (DCTPP1), an enzyme that regulates the cellular nucleotide pool. The heterodimer binds significantly more tightly than each of its individual monomers. The activity of DCTPP1 is elevated in certain types of tumours, promoting the invasion, migration, and proliferation of the cancer cells while also inhibiting programmed cell death. It can also help cancer cells to resist treatment. Bipoterpride 2 inhibits this enzymatic activity and disrupts the now pathologically altered amino acid metabolism in the tumour cells.
The team was thus able to identify DCTPP1 as a new target for the treatment of colorectal cancer and bipoterprides as new potential drug candidates.
Scientists at Trinity College Dublin have discovered a new process in the immune system that leads to the production of an important family of anti-viral proteins called interferons. They hope the discovery will now lead to new, effective therapies for people with some autoimmune and infectious diseases.
Reporting in Nature Metabolism, Luke O’Neill, Professor of Biochemistry in the School of Biochemistry and Immunology at Trinity, and his team have found that a natural metabolite called Itaconate can stimulate immune cells to make interferons by blocking an enzyme called SDH.
Co-lead author, Shane O’Carroll, from Trinity’s School of Biochemistry and Immunology, said: “We have linked the enzyme SDH to the production of interferons in an immune cell type called the macrophage. We hope our work will help the effort to develop better strategies to fight viruses because interferons are major players in how our innate immune system eliminates viruses – including COVID-19.”
Co-lead author, Christian Peace, from Trinity’s School of Biochemistry and Immunology, added: “Itaconate is a fascinating molecule made by macrophages during infections. It’s already known to suppress damaging inflammation but now we have found how it promotes anti-viral interferons.”
Working with drug companies Eli Lilly and Sitryx Ltd, the next step is to test new therapies based on Itaconate in various diseases, with some autoimmune diseases and some infectious diseases on the likely list. And the work potentially extends to other disease contexts in which SDH is inhibited, such as cancer, and could reveal a new therapeutic target for SDH-deficient tumours.
Prof O’Neill said: “With Itaconate you get two for the price of one – not only can it block harmful inflammation, but it can also help fight infections. We have discovered important mechanisms for both and the hope now is that patients will benefit from new therapies that exploit Itaconate and its impacts.”
Clinical trials in patients are set to start next year.
In June, we heard what could be this year’s biggest HIV breakthrough: a twice-yearly injection can prevent HIV infection. Findings from a second large study of the jab has now confirmed that it works. Elri Voigt goes over the new findings and unpacks the licenses that are expected to facilitate the availability of generic versions of the jab in over a hundred countries, including South Africa.
The second of two pivotal studies of a six-monthly HIV prevention injection containing the antiretroviral drug lenacapavir has confirmed that the jab works remarkably well.
The first study, called PURPOSE 1, found that the jab is safe and highly effective at preventing HIV infection in women. The second, called PURPOSE 2, found the same for cisgender men, transgender men, transgender women and non-binary people who have sex with men assigned male at birth.
Interim findings from PURPOSE 2 were presented last week at the HIV Research for Prevention (HIVR4P) conference in Lima, Peru.
The researchers compared the safety and efficacy of lenacapavir injections every six months to a daily HIV prevention pill – a combination of emtricitabine and tenofovir disoproxil fumarate, called F/TDF. The results have not yet been published in a peer reviewed journal, but is expected to be soon, according to Principal Investigator for PURPOSE 2 Dr Colleen Kelley, a professor of medicine at Emory University’s School of Medicine.
In the PURPOSE 1 study, none of the 2 134 people receiving the lenacapavir injection got HIV during the study. In PURPOSE 2, there were two HIV infections among the 2 179 people receiving the injection. These numbers are dramatically better than those for HIV prevention pills and for people in the communities where the study was done who were not receiving prevention injections or pills.
These findings mean the evidence is now in place for the manufacturer, Gilead Sciences, to file with regulatory authorities to register lenacapavir injections for HIV prevention. Such registration is required before the jab can be marketed for prevention. Lenacapavir injections are already registered in some countries as a last resort treatment for HIV, but not yet in South Africa.
“Now that we have a comprehensive dataset across multiple study populations, Gilead will work urgently with regulatory, government, public health and community partners to ensure that, if approved, we can deliver twice-yearly lenacapavir for PrEP worldwide, for all those who want or need PrEP,” Daniel O’Day, the chairperson and Chief Executive Officer of Gilead said in a press release. (PrEP, or pre-exposure prophylaxis, refers to taking antiretrovirals to prevent HIV infection.)
Top line findings
The interim results presented at HIVR4P by Kelley, showed that when compared to the background HIV incidence calculated in the study, lenacapavir reduced HIV infections by 96%. And when compared to the F/TDF prevention pill, the injection reduced HIV infections by 89%.
Among the 3 265 participants enrolled in the study, 11 people acquired HIV- two of the 2 179 people who were assigned to the lenacapavir arm and nine of the 1 086 participants assigned to the prevention pill arm. This translated to HIV incidence of 0.93 per 100 person years in the prevention pill arm compared to only 0.1 per 100 person years in the lenacapavir arm.
This was compared to the background incidence, which was determined when screening eligible participants for HIV. Out of 4 634 people screened for the study, 378 or 8.2% were diagnosed with HIV. Based on further laboratory testing, it was estimated that of those 378 people, 45 or 11.9% recently acquired HIV (classified as being within the last 120 days or so). This latter group provided the background HIV incidence, which was estimated to be 2.37 per 100 person years.
This is a novel study design, Kelley told Spotlight, because this calculation was used to estimate the HIV incidence that would have occurred in a placebo group without actually enrolling a placebo group.
“It’s no longer ethical to have a placebo group in HIV PrEP trials because we know that we have effective PrEP agents,” she said. “Yet, it’s almost essential to have a placebo group when you design a clinical trial so that you can really say how effective your medication, your new agent is [compared] to having nothing.”
When asked at a press conference about the two breakthrough infections in the lenacapavir arm, Kelley said the analysis for this is ongoing and will hopefully be available at a future conference and in a journal soon. She said that the two breakthrough infections in the lenacapavir arm were detected by routine testing during the study.
Principal Investigator for PURPOSE 2 Professor Colleen Kelley at the 5th HIV Research for Prevention Conference in Lima, Peru. (Photo: Nicole Bergman/IAS)
Kelley added that around 90% of participants in the two study arms were able to receive their injection on time. “So, we at least know that the injections were delivered in a timely fashion for almost all participants,” she said.
Whether or not the two infections occurred in people who had received the jabs on time and according to the study protocol will be closely watched as more study details is shared in the coming months.
To be enrolled in the study, participants had to meet several criteria. They had to be older than 16, never received HIV prevention injections before, weigh more than 35kg, have good kidney function, not have been tested for HIV in the last 12 weeks, and had to have been sexually active in the last 12 months.
All study participants were given a pill a day and an injection, those in the lenacapavir arm received two 1.5 ml lenacapavir injections every six months and a daily placebo pill, while those in the prevention pill arm received the daily F/TDF pill and a placebo injection every six months.
The study was conducted across seven countries, with 6 sites located in South Africa and others in Argentina, Brazil, Mexico, Peru, Thailand, and the United States, according to study data on Gilead’s website.
Safety data
Overall, Kelley said lenacapavir was safe and well-tolerated despite some side effects, mainly related to the injections. A total of 43 people dropped out of the study due to side effects.
The most common adverse event in the study was injection site reactions. There were more injection site reactions in the lenacapavir arm compared to the prevention pill arm. 29 people dropped out of the study because of these, 26 in the lenacapavir arm and 3 in the prevention pill arm (people in this study arm received placebo jabs).
The most common injection site reaction were subcutaneous nodules – these are harmless, usually invisible, small lumps under the skin. Nodules occur because lenacapavir is injected under the skin where it forms a drug depot. Injection site reactions and nodule size decreased with subsequent injections. This side effect and trend of decreasing reactions was also noted in the PURPOSE 1 study. Other injection site reactions were pain and erythema which is a type of skin rash.
According to Kelley, there were no serious adverse events related to injection site reactions.
When injection site reactions are excluded, according to Kelley, the other adverse events were similar across both arms, with 74% of participants in each arm experiencing an adverse event. The majority were mild or moderate.
Seven participants in each study arm dropped out due to side effects that weren’t related to injection site reactions. Those who discontinued from the lenacapavir arm will be given prevention pills for a year. This is done to protect these participants, Kelley explained, from potentially acquiring HIV when lenacapavir levels wane, as well as to reduce the risk of potential drug resistance developing.
There were a few serious adverse events, although Kelley told Spotlight she does not currently have any additional information on what these were. She explained that a serious adverse event is generally classified as something like hospitalisation, a life-threatening condition, an important medical event or adverse pregnancy outcome.
“Usually when we look at something like this, we look at the rates compared in the two arms of the study and it was 3% in the LEN [lenacapavir] arm and 4% in the F/TDF arm, so they were equal, essentially the same in both study arms,” Kelly said.
There were six deaths during the study, but none were related to the study drugs.
Next steps for lenacapavir
Now that the interim results have been announced, both studies have been unblinded and entered an open-label phase where participants have the choice of switching to or continuing with the injection.
Professor Linda-Gail Bekker, the Chief Executive Officer at the Desmond Tutu Health Foundation, recently said on a webinar hosted by the South African Health Technologies Advocacy Coalition, that study participants are now able to use the PrEP option they’d prefer – either oral PrEP or the injection. This means all participants will be able to access lenacapavir through the studies if they wanted to use it.
But it will likely be a while before anyone outside of these studies can access lenacapavir as HIV prevention.
“This is an incredible intervention. Now we have to make sure everyone can get it and that’s going to be the most important next step, ensuring that everyone who needs this drug has access,” Kelley told Spotlight.
Gilead’s generic licensing agreement and pricing
What we do know so far about the next steps for lenacapavir is that the process to allow for generic manufacturing has started. This month, Gilead released its voluntary licensing agreements with six generic companies for manufacturing cheaper versions of lenacapavir.
Dr Andrew Gray, a senior lecturer in Pharmacology at the University of KwaZulu-Natal, told Spotlight that no South African firms have been included in the voluntary licenses – four of the generic licensees are in India, one is in Pakistan, and one is in Egypt.
“In essence, they [the generic companies] are allowed to sell their generic versions in a number of identified countries, specified by Gilead,” Gray said. The agreement lists 120 countries, including South Africa.
Gilead itself will also be prioritising the registration of lenacapavir in 18 countries, which it said represent about 70% of the HIV burden in the countries named in the license. The list includes South Africa, Uganda, and Botswana. Gilead says it will start filing for registration with regulatory authorities by the end of the year.
It will be important to see how quickly Gilead seeks regulatory approval for lenacapavir with the South African Health Products Regulatory Authority (SAHPRA), Gray said. Registration with SAHPRA will be required before the injection can be rolled out in South Africa.
In putting together this timeline, we’ve spoken to several well-placed experts, but we stress that this is very much a back-of-the-envelope exercise and far from set in stone. (Infograph: Spotlight)
Some countries won’t be able to procure generics
Gilead received criticism for several omissions from the list of countries that the generic manufacturers can sell to. The US-based HIV advocacy group AIDS Vaccine Advocacy Coalition, among others, pointed out the exclusion of several countries which have high HIV incidence. Some of those countries participated in PURPOSE 2- namely Brazil, Argentina, Mexico and Peru.
A spokesperson from Gilead told Spotlight the manufacturer’s access policy included tailored approaches to ensure rapid and broad access of lenacapavir and it objectively considered the countries where a voluntary licence would provide the most benefit.
“Gilead’s voluntary licence primarily covers countries based on economic need and HIV burden, which are primarily low- and lower-middle income countries. The voluntary licence also covers certain middle-income countries with limited access to healthcare,” the spokesperson said.
Acknowledging that some middle-income countries do have a high HIV burden, Gilead is “exploring several innovative strategies to support access to LEN for PrEP (if approved), including tiered pricing, and are working with payors to establish fast, efficient pathways to help reach people who need or want PrEP”, said the spokesperson.
“Ensuring access in middle-income and upper-middle income countries, including those in Latin America, is a priority for Gilead. Planning for these countries, incorporating input from advocates and global health organizations, is ongoing and updates will be shared as discussions progress,” the spokesperson added. “Additionally, Gilead is committed to ensuring that individuals who participated in the PURPOSE studies have been offered and will be able to stay on open label lenacapavir until it is available in their country.”
The company’s decision to license generic manufacturers directly is at odds with earlier calls from several activist groups and UNAIDS to license via the UN-backed Medicines Patent Pool.
Pricing
It will also be important to see if Gilead will disclose a single exit price for the South African market, according to Gray.
In its press release announcing the voluntary licensing agreement, Gilead stated it will “support low-cost access to the drug in high-incidence, resource-limited countries through a two-part strategy: establishing a robust voluntary licensing program and planning to provide Gilead-supplied product at no profit to Gilead until generic manufacturers are able to fully support demand”.
It is too early in the process to reveal a price for lenacapavir yet, the spokesperson from Gilead told Spotlight.
“While Gilead prepares for global regulatory filings, it is too early to disclose the price of lenacapavir for HIV prevention. Our pledge is to price our medicines to reflect the value they deliver to people, patients, healthcare systems and society. For Gilead-branded lenacapavir, we do plan to price it at no profit to Gilead in 18 select high-incidence, resource-limited countries until generic manufacturers are able to fully support demand,” the spokesperson said.
Spotlight previously reported on research that estimated that if produced at sufficient volumes, the price of lenacapavir could be drastically reduced to levels likely considered affordable by the South African government. For instance, if enough volume was produced to supply 10 million people with PrEP, the price for the injection could be as low as $40 (under R800) per person per year. At the moment, Gilead supplies lenacapavir for HIV treatment in wealthy countries for about $40 000 per person per year.
Gilead’s lenacapavir product will be the first to register in South Africa and will almost certainly be the only lenacapavir product available here for several years – that is because it is expected to take generic manufacturers a few years before they can start producing generic lenacapavir. Based on calculations made for other PrEP products, it seems unlikely that the Department of Health would be willing to procure lenacapavir at a price significantly above R1 000 per person per year. The HIV prevention pill currently costs government around R800 per person per year.
Initial prescriptions of benzodiazepines, a class of drugs used to treat anxiety and sleep problems after a stroke may include too many pills for adults ages 65 or older, finds new study in the Stroke journal
Photo by Towfiqu Barbhuiya on Unsplash
Although there has been a slight downward trend in the prescription of benzodiazepines (depressants that relieve anxiety, muscle spasms, produce sedation and reduce seizures) among older adults over the last decade, the rate of first-time prescriptions for these medications after an ischaemic stroke is still sizable, according to research published today in Stroke.
After a stroke, benzodiazepines may be used to calm anxiety and improve sleep, but also have a potential for abuse and addiction. When prescribed to older adults, these medications may increase the risk of falls and broken bones, as well as memory problems, confusion and other harmful effects.
Researchers reviewed data from Medicare claims in the US and analysed 10 years of first-time prescriptions for benzodiazepines among more than 120 000 people, ages 65 and older, who were hospitalised for ischaemic stroke. The rate of benzodiazepine prescriptions during the first three months after stroke were examined, and data were adjusted for race, sex and ethnicity. Then year-to-year prescription patterns were reviewed to identify the number of potentially excessive new benzodiazepine prescriptions given to stroke survivors.
“We reviewed stroke survivors at 90 days after a stroke because that window of time is critical for rehabilitation of motor, speech and cognitive function, as well as mental health. It’s often a very difficult time for patients who experience loss of mobility and independence. Benzodiazepines may inhibit recovery and rehabilitation,” said study co-author Julianne Brooks, MPH, a data analytics manager at the Center for Value-based Healthcare and Sciences at Massachusetts General Brigham in Boston. “For this older age group, guidelines recommend that benzodiazepine prescriptions should be avoided if possible. However, there may be cases where benzodiazepines are prescribed to be used as needed. For example, to treat breakthrough anxiety, a provider may prescribe a few pills and counsel the patient that the medication should only be used as needed. The increased risks of dependence, falls and other harmful effects should be discussed with the patient.”
The study found:
Within 90 days of stroke, 6127 (4.9%) people were started on a benzodiazepine for the first time.
Lorazepam (40%) and alprazolam (33%) were the most-prescribed benzodiazepine medications.
Three-quarters of the first-time benzodiazepine prescriptions were for a supply of over seven days, and more than half of the prescriptions were for a supply between 15 to 30 days.
Prescription rates were higher among women (5.5%) than men (3.8%).
Prescription fill rates were also higher in Hispanic adults (5.8%), though this group was limited by the small number of participants – 1.9% of the overall sample.
Overall, prescription rates were highest in the Southeast (5.1%) and lowest in the Midwest (4%) of the US. “The Southeast region is the stroke belt with a higher rate of strokes, so that could explain some differences in care in that region,” Brooks said.
There was an overall modest nationwide decline of initial prescriptions from 2013 to 2021 of 1.6%.
“We found a pattern of potential oversupply with these initial benzodiazepine prescriptions, which would be enough for patients to become long-term users or possibly addicted. The benzodiazepine prescriptions given under these circumstances may lead to dependence,” Brooks said. “Increased awareness and improved recommendations about the risks of these medications for older stroke survivors are needed.
“Although the overall prescription rate decreased slightly over 10 years, this prescription pattern is still a problem. It’s concerning because older adults are vulnerable to overprescribing and adverse outcomes. We know from previous studies that vulnerable and marginalized populations experience worse outcomes after stroke, so we want to understand the factors that may play a role so we can provide better care,” Brooks said.
The 2019 American Geriatrics Society Beers Criteria maintains a list of medications that health care professionals can reference to safely prescribe medications for adults older than 65. Beers criteria recommends avoiding benzodiazepines in all older adults due to the risk of cognitive impairment, delirium, falls, fractures and motor vehicle crashes.
“Other guidelines also suggest behavioural interventions such as cognitive behaviour therapy for insomnia, antidepressant medications for anxiety disorders and trying non-pharmaceutical interventions first,” Brooks said.
Researchers said more studies are needed to understand if there is a safe level for prescribing benzodiazepines that may be most appropriate for older adults. The main limitation was that this study used a large, national dataset that did not include information about why benzodiazepines were prescribed.
