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	<title>PET/CT imaging &#8211; Science</title>
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	<title>PET/CT imaging &#8211; Science</title>
	<link>https://scienmag.com</link>
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		<title>Blood Pressure Drug Losartan Awakens Metabolic Brown Fat in Surprise Discovery</title>
		<link>https://scienmag.com/blood-pressure-drug-losartan-awakens-metabolic-brown-fat-in-surprise-discovery/</link>
		
		<dc:creator><![CDATA[Daisy Hatcher]]></dc:creator>
		<pubDate>Sat, 17 Oct 2026 08:28:39 +0000</pubDate>
				<category><![CDATA[Medicine]]></category>
		<category><![CDATA[angiotensin receptor blockers]]></category>
		<category><![CDATA[anxiety]]></category>
		<category><![CDATA[brown adipose tissue]]></category>
		<category><![CDATA[brown adipose tissue activation]]></category>
		<category><![CDATA[brown fat]]></category>
		<category><![CDATA[cardiovascular medications]]></category>
		<category><![CDATA[Depression]]></category>
		<category><![CDATA[drug repurposing]]></category>
		<category><![CDATA[energy expenditure]]></category>
		<category><![CDATA[glucose metabolism]]></category>
		<category><![CDATA[hypertension]]></category>
		<category><![CDATA[losartan]]></category>
		<category><![CDATA[Machine learning]]></category>
		<category><![CDATA[metabolic health]]></category>
		<category><![CDATA[metabolic syndrome]]></category>
		<category><![CDATA[metabolism]]></category>
		<category><![CDATA[Mitochondrial Function]]></category>
		<category><![CDATA[obesity and diabetes management]]></category>
		<category><![CDATA[obesity treatment]]></category>
		<category><![CDATA[PET/CT imaging]]></category>
		<category><![CDATA[repurposing existing drugs]]></category>
		<category><![CDATA[thermogenesis]]></category>
		<category><![CDATA[white vs brown fat]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=295826</guid>

					<description><![CDATA[Rockefeller University researchers found that the common blood pressure drug losartan stimulates metabolically active brown fat in mice and is associated with better cardiometabolic and psychiatric health in over 100,000 patients.]]></description>
										<content:encoded><![CDATA[<p>In a finding that could reshape how clinicians think about one of the most widely prescribed classes of cardiovascular medications, researchers at The Rockefeller University have discovered that losartan, a mainstay treatment for high blood pressure, appears to stimulate brown adipose tissue, the specialized fat long associated with improved metabolic and cardiovascular health. The study, published in Nature by a team led by Paul Cohen of Rockefeller&#8217;s Laboratory of Molecular Metabolism, in collaboration with Heiko Schöder and Daniel Lafontaine of Memorial Sloan Kettering Cancer Center, suggests that repurposing an established angiotensin receptor blocker with a decades-long safety record may offer a clinically viable route to activating a tissue that most adults carry only in small, dormant quantities.</p>
<p>Brown adipose tissue, or BAT, differs fundamentally from the white fat that stores excess energy. Packed with mitochondria, brown fat burns calories to generate heat, a process known as non-shivering thermogenesis. In humans, deposits sit in six principal regions of the body, including the neck, the armpits, and the areas surrounding organs such as the heart and kidneys. Because active brown fat consumes glucose and fatty acids, researchers have suspected for years that boosting its activity could help combat obesity, diabetes, and heart disease. What has been missing is a safe, practical pharmacological switch, and the new work points to a candidate that has been sitting in medicine cabinets all along.</p>
<p>The road to that candidate began with an unusually rich dataset. In 2021, Cohen&#8217;s laboratory characterized roughly 50,000 patients from Memorial Sloan Kettering Cancer Center, finding that people whose scans revealed brown fat had significantly lower odds of cardiometabolic diseases, including coronary artery disease and type II diabetes. That analysis, however, had been deliberately narrow. &#8220;We only looked for a few diagnostic codes in that study, mainly focusing on cardiovascular disease since that&#8217;s what this tissue has historically been associated with,&#8221; Cohen says. &#8220;The scope of this new analysis is far more expansive. We doubled our number of patients and considered more than 500 codes, which allowed us to unearth many new insights.&#8221;</p>
<p>The expanded investigation adopted what the team describes as a reverse translational approach, working backward from clinical observations to uncover the molecular mechanisms beneath them. First author Nicolás Gómez-Banoy, an endocrinologist and instructor in clinical investigation in Cohen&#8217;s laboratory, analyzed PET/CT scans from more than 100,000 patients. These imaging studies had originally been performed as part of routine cancer surveillance, but they inadvertently captured brown fat activity whenever the tissue lit up on the scans. Gómez-Banoy applied a machine learning tool developed by colleagues at MSKCC to quantify the total degree of BAT activity in each patient, along with the activity in each of the six anatomical regions where the tissue resides.</p>
<p>That regional breakdown proved to be one of the study&#8217;s most striking technical contributions. Location mattered, and it mattered differently depending on the disease in question. &#8220;For example, the axillary, or armpit, area was linked to a decreased risk of high blood pressure compared to other regions,&#8221; Gómez-Banoy says. Across the cohort as a whole, patients with detectable brown fat showed better glycemic parameters, healthier lipid profiles, more favorable echocardiographic indices, and lower levels of inflammatory markers than patients without it. The pattern held across diagnoses, suggesting that brown fat is not merely a bystander in metabolic health but an active participant whose influence radiates through multiple organ systems.</p>
<p>When the researchers cross-referenced medication histories against scan findings, a clear signal emerged: patients taking angiotensin receptor blockers had a higher presence of brown fat in their imaging. To determine whether the association was causal, the team turned to controlled laboratory experiments. In cultured brown fat cells, losartan directly increased metabolic activity, demonstrating that the drug acts on the tissue itself rather than through some indirect systemic effect. Critically, the molecular interactions through which losartan enhanced brown fat turned out to be distinct from the pathways responsible for its well-known blood pressure-lowering properties. &#8220;The fact that its different effects are mediated by different molecular pathways is advantageous, since it means we could potentially isolate them in future therapies,&#8221; Gómez-Banoy says. &#8220;That way you would be able to stimulate brown fat in people with normal blood pressure.&#8221;</p>
<p>The team then extended the work into living animals. Healthy mice treated with losartan exhibited a constellation of metabolic enhancements, including increased energy expenditure, elevated oxygen consumption, and greater carbon dioxide production, all while maintaining a steady body weight. That combination, burning more fuel without losing weight, hints at a rebalancing of energy metabolism rather than a simple caloric drain. For a drug already taken daily by millions of patients worldwide, the prospect of a second, metabolically beneficial mode of action is precisely the kind of repurposing opportunity that drug developers rarely encounter, because the safety profile has already been established through decades of clinical use.</p>
<p>Perhaps the most unexpected dimension of the study concerns the mind rather than the body. The expanded diagnostic analysis revealed a lower incidence of anxiety and depression among patients with brown fat, a connection reported for the first time in this research. &#8220;We know that metabolically healthy people tend to have lower incidence of psychiatric diseases, so it could be that having brown fat makes you more metabolically healthy, and this correlates with fewer psychiatric issues,&#8221; Gómez-Banoy says. The relationship runs in both directions, it seems: the team found that selective serotonin reuptake inhibitors, the antidepressants most commonly prescribed for depression, had a dampening effect on brown fat activity. Whether that dampening has clinical consequences for metabolism remains an open question, but it adds a new consideration to the long list of trade-offs physicians weigh when selecting psychiatric medications.</p>
<p>The findings open several avenues for future research. The team plans to study the genetics of people who naturally carry high levels of brown fat, to probe the mechanisms linking BAT to anxiety and depression, and to investigate potential downsides, including higher rates of osteoporosis and skin diseases observed in people with the tissue. Beyond losartan, the massive cohort analysis flagged numerous other medications associated with brown fat activity, some of which may prove even more potent or more selective stimulators of the tissue. &#8220;There were plenty of other medications associated with brown fat activity in our large cohort,&#8221; Cohen notes. &#8220;This is just a start.&#8221;</p>
<p>For now, the study stands as a compelling example of what large-scale analysis of incidental clinical data can reveal. More than 100,000 cancer surveillance scans, collected for entirely different reasons, became a window into human metabolism when paired with machine learning and a willingness to ask broad questions. The result is a hypothesis with immediate translational appeal: a drug that is cheap, widely available, and already proven safe may quietly be doing more than lowering blood pressure. Confirming that promise will require prospective clinical trials in diverse populations, but the idea that the path to healthier metabolism might run through the pharmacy&#8217;s oldest shelves is exactly the kind of surprise that keeps metabolic science, and its growing audience, watching closely.</p>
<p><strong>Subject of Research:</strong> Repurposing the angiotensin receptor blocker losartan to stimulate brown adipose tissue and improve metabolic health</p>
<p><strong>Article Title:</strong> Researchers discover a commonly prescribed blood-pressure drug may stimulate “healthy” brown fat</p>
<p><strong>Article References:</strong> Researchers discover a commonly prescribed blood-pressure drug may stimulate “healthy” brown fat. (n.d.). <a href="https://www.eurekalert.org/news-releases/1147521" rel="noopener noreferrer">Original publication</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> Not provided</p>
<p><strong>Keywords:</strong> brown fat, losartan, brown adipose tissue, metabolism, angiotensin receptor blockers, hypertension, PET/CT imaging, machine learning, anxiety, depression, energy expenditure, drug repurposing</p>
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		<post-id xmlns="com-wordpress:feed-additions:1">295826</post-id>	</item>
		<item>
		<title>PET Imaging May Spare Patients Risky Drug Withdrawal Before Adrenal Vein Test</title>
		<link>https://scienmag.com/pet-imaging-may-spare-patients-risky-drug-withdrawal-before-adrenal-vein-test/</link>
		
		<dc:creator><![CDATA[Ophelia Keating]]></dc:creator>
		<pubDate>Mon, 12 Oct 2026 13:43:31 +0000</pubDate>
				<category><![CDATA[Medicine]]></category>
		<category><![CDATA[68Ga-pentixafor]]></category>
		<category><![CDATA[68Ga-Pentixafor PET/CT]]></category>
		<category><![CDATA[adrenal gland tumor localization]]></category>
		<category><![CDATA[adrenal vein sampling]]></category>
		<category><![CDATA[adrenal vein sampling risks]]></category>
		<category><![CDATA[adrenal venous sampling]]></category>
		<category><![CDATA[adrenalectomy]]></category>
		<category><![CDATA[aldosterone-producing adenoma]]></category>
		<category><![CDATA[curable secondary hypertension]]></category>
		<category><![CDATA[CXCR4]]></category>
		<category><![CDATA[endocrine disorders]]></category>
		<category><![CDATA[hypertension]]></category>
		<category><![CDATA[hypertension treatment planning]]></category>
		<category><![CDATA[lateralization]]></category>
		<category><![CDATA[mineralocorticoid receptor antagonist therapy]]></category>
		<category><![CDATA[mineralocorticoid receptor antagonists]]></category>
		<category><![CDATA[molecular imaging]]></category>
		<category><![CDATA[non-invasive diagnostic techniques]]></category>
		<category><![CDATA[novel molecular imaging in endocrine disorders]]></category>
		<category><![CDATA[nuclear medicine]]></category>
		<category><![CDATA[PET/CT imaging]]></category>
		<category><![CDATA[primary aldosteronism]]></category>
		<category><![CDATA[secondary hypertension diagnosis]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=264823</guid>

					<description><![CDATA[A prospective study finds that 68Ga-Pentixafor PET/CT matches adrenal venous sampling in lateralizing aldosterone-producing adenomas even when patients remain on mineralocorticoid receptor antagonist therapy.]]></description>
										<content:encoded><![CDATA[<p>Primary aldosteronism is the most common form of secondary hypertension, a condition in which tiny hormone-secreting tumors on the adrenal glands drive blood pressure to dangerous heights by flooding the body with aldosterone. For decades, the gold standard for deciding which adrenal gland is the culprit has been adrenal venous sampling, or AVS, a technically demanding catheter procedure that requires patients to stop their mineralocorticoid receptor antagonists for at least four weeks beforehand. A new prospective study published in BMC Endocrine Disorders suggests that a molecular imaging technique called 68Ga-Pentixafor PET/CT could match the diagnostic performance of AVS even in patients who cannot safely interrupt their medication, a finding that may reshape how clinicians work up this curable form of hypertension.</p>
<p>The study, conducted at the First Affiliated Hospital of Fujian Medical University in Fuzhou, China, and registered as clinical trial NCT05188872, prospectively enrolled 98 patients with biochemically confirmed primary aldosteronism. All participants underwent both successful bilateral adrenal venous sampling and 68Ga-Pentixafor PET/CT. The primary analysis focused on 41 patients who had a CT-detected unilateral adrenal adenoma meeting predefined radiological criteria. Of these, 21 were receiving continuous mineralocorticoid receptor antagonist therapy before lateralization testing, while 20 were not, allowing the researchers to directly test whether the drugs distort the imaging signal.</p>
<p>The technical logic behind the comparison is elegant. 68Ga-Pentixafor is a radiolabeled tracer that binds to the chemokine receptor CXCR4, which is overexpressed on the cells of aldosterone-producing adenomas. When injected into a patient, the tracer accumulates in the hormone-producing lesion, and a combined positron emission tomography and computed tomography scan reveals exactly which adrenal gland harbors the overactive tissue. In principle, this offers a non-invasive window into adrenal function that a standard CT scan, which can only show anatomy, cannot provide. The critical question was whether medications that block the mineralocorticoid receptor would blunt this signal and cause the imaging to disagree with AVS.</p>
<p>That question matters because the current guidelines create a genuine clinical dilemma. Mineralocorticoid receptor antagonists such as spironolactone are often the only drugs capable of controlling blood pressure and restoring potassium levels in these patients. Withdrawing them for four or more weeks, as AVS protocols demand, can expose patients to refractory hypertension, dangerous hypokalemia, and heightened cardiovascular risk. For many patients, particularly those with severe disease, the recommended washout period is simply unfeasible. A reliable imaging alternative that works regardless of medication status would therefore fill a real gap in clinical practice.</p>
<p>The researchers&#8217; findings were strikingly reassuring. Baseline aldosterone and serum potassium levels were comparable between the medicated and unmedicated groups, with the only significant biochemical difference being a higher direct renin concentration in the MRA group, an expected pharmacological effect of receptor blockade. When the team determined the optimal imaging threshold, an SUVmax cutoff of 7.60 yielded a maximum Youden index of 0.907, indicating excellent discriminatory performance for identifying the hormone-secreting side. The concordance between 68Ga-Pentixafor PET/CT and AVS was 90.00 percent in the non-medicated group and 85.71 percent in the medicated group, a difference that was not statistically significant.</p>
<p>Importantly, this high agreement held up under further scrutiny. The researchers stratified their results by the laterality of the lesion and by the diameter of the CT-detected adenoma, and the concordance remained consistently high across all subgroups. This robustness matters because adrenal adenomas vary widely in size, and smaller nodules are precisely the ones where anatomical imaging alone is least informative. The fact that tracer uptake continued to lateralize correctly in patients on continuous receptor antagonist treatment suggests that CXCR4 expression on aldosterone-producing cells is not meaningfully suppressed by the drugs, at least within the studied population.</p>
<p>The study did not stop at diagnostic agreement; it also followed patients through treatment. Among those who underwent laparoscopic adrenalectomy, the postoperative clinical and biochemical success rates, whether complete or partial, were 88.89 percent and 94.44 percent in the non-medicated group, compared with 85.71 percent and 92.86 percent in the medicated group. No significant differences were observed between the two cohorts. In other words, patients identified for surgery by the imaging pathway did just as well as those identified through the conventional route, providing an outcome-based validation of the imaging approach rather than a purely radiological one.</p>
<p>The implications extend beyond the technical question of drug washout. Adrenal venous sampling, while accurate in experienced hands, is an invasive procedure with a notable failure rate, since catheterizing the small right adrenal vein is notoriously difficult and success depends heavily on operator expertise and center volume. It is also costly and uncomfortable for the patient. A non-invasive scan that can be performed as an outpatient, without catheters or medication withdrawal, could dramatically simplify the diagnostic pathway for the many patients worldwide whose hypertension is driven by a unilateral aldosterone-producing adenoma and who could be cured with a targeted operation.</p>
<p>The authors are careful to frame the result appropriately. In this selected cohort of primary aldosteronism patients with a CT-detected unilateral adrenal adenoma, 68Ga-Pentixafor PET/CT showed high concordance with AVS, including among patients receiving continuous mineralocorticoid receptor antagonist therapy. They position the technique as a complementary, non-invasive tool for selected patients in whom AVS is technically challenging or in whom medication withdrawal would be clinically unsafe, rather than as an outright replacement for the established gold standard. The cohort size of the primary analysis, 41 patients split into two groups, is modest, and broader validation in larger and more diverse populations will be needed before guidelines change.</p>
<p>Nevertheless, the study represents a meaningful step toward personalized, less invasive care for a disease that affects an estimated five to ten percent of people with hypertension and remains underdiagnosed in many health systems. If larger trials confirm these results, patients with refractory hypertension and a visible adrenal nodule could one day undergo a single PET/CT scan, keep the medications that keep them safe, and proceed directly to curative surgery without ever entering an interventional radiology suite. For a condition whose burden falls disproportionately on patients whose blood pressure resists multiple drugs, that would be a genuinely transformative shift in practice.</p>
<p><strong>Subject of Research:</strong> Concordance of 68Ga-Pentixafor PET/CT with adrenal venous sampling for lateralizing primary aldosteronism during mineralocorticoid receptor antagonist treatment</p>
<p><strong>Article Title:</strong> Impact of continuous mineralocorticoid receptor antagonist treatment on the concordance between 68Ga-Pentixafor PET/CT and adrenal venous sampling in primary aldosteronism patients with a CT-detected unilateral adrenal adenoma</p>
<p><strong>Article References:</strong> Yao, Y., Zhan, Y., Zhang, Q., Lin, K., Chen, Z., Lin, J., Peng, F., Fang, Z., &amp; Cai, H. (2026). Impact of continuous mineralocorticoid receptor antagonist treatment on the concordance between 68Ga-Pentixafor PET/CT and adrenal venous sampling in primary aldosteronism patients with a CT-detected unilateral adrenal adenoma. <em>BMC Endocrine Disorders</em>. <a href="https://doi.org/10.1186/s12902-026-02645-9" rel="noopener noreferrer">https://doi.org/10.1186/s12902-026-02645-9</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1186/s12902-026-02645-9" rel="noopener noreferrer">10.1186/s12902-026-02645-9</a></p>
<p><strong>Keywords:</strong> primary aldosteronism, 68Ga-Pentixafor PET/CT, adrenal venous sampling, mineralocorticoid receptor antagonists, aldosterone-producing adenoma, lateralization, hypertension, molecular imaging, CXCR4, adrenalectomy, nuclear medicine, endocrine disorders</p>
]]></content:encoded>
					
		
		
		<post-id xmlns="com-wordpress:feed-additions:1">264823</post-id>	</item>
		<item>
		<title>Largest Global Study of Rare Fungal Infection Finds Drug Choice May Matter Less Than Immune Recovery</title>
		<link>https://scienmag.com/largest-global-study-of-rare-fungal-infection-finds-drug-choice-may-matter-less-than-immune-recovery/</link>
		
		<dc:creator><![CDATA[Kristina Jarvis]]></dc:creator>
		<pubDate>Thu, 24 Sep 2026 21:39:03 +0000</pubDate>
				<category><![CDATA[Medicine]]></category>
		<category><![CDATA[antifungal drug efficacy in hematological malignancies]]></category>
		<category><![CDATA[antifungal therapy]]></category>
		<category><![CDATA[antifungal therapy outcomes]]></category>
		<category><![CDATA[azoles]]></category>
		<category><![CDATA[beta-D-glucan]]></category>
		<category><![CDATA[blood cancer complications and fungal infections]]></category>
		<category><![CDATA[Candida tropicalis]]></category>
		<category><![CDATA[chronic disseminated candidiasis]]></category>
		<category><![CDATA[echinocandins]]></category>
		<category><![CDATA[fluconazole resistance]]></category>
		<category><![CDATA[haematological malignancies]]></category>
		<category><![CDATA[hepatosplenic candidiasis]]></category>
		<category><![CDATA[hepatosplenic candidiasis treatment]]></category>
		<category><![CDATA[immune reconstitution]]></category>
		<category><![CDATA[immune system recovery in fungal infections]]></category>
		<category><![CDATA[impact of immune recovery on fungal infection prognosis]]></category>
		<category><![CDATA[international study on rare fungal infections]]></category>
		<category><![CDATA[long-term management of fungal infections in cancer patients]]></category>
		<category><![CDATA[neutropenia]]></category>
		<category><![CDATA[neutropenia recovery and fungal disease outcomes]]></category>
		<category><![CDATA[PET/CT imaging]]></category>
		<category><![CDATA[role of immune reconstitution in infection management]]></category>
		<category><![CDATA[treatment response in disseminated candidiasis]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=212739</guid>

					<description><![CDATA[The largest multinational cohort of chronic disseminated candidiasis finds that antifungal drug class does not significantly affect outcomes, pointing instead to immune recovery and shorter, individualised treatment.]]></description>
										<content:encoded><![CDATA[<p>Chronic disseminated candidiasis, a rare and feared fungal complication of cancer treatment, has long been managed with months of antifungal therapy and repeated imaging, largely on the basis of small, single-centre studies. Now the largest international cohort ever assembled has delivered a finding that could reshape how clinicians approach the disease: the class of antifungal drug chosen first appears to make little difference to survival or treatment response, while recovery of the patient&#8217;s own immune system emerges as the dominant force determining outcome.</p>
<p>The study, published in eClinicalMedicine, brought together 111 adults with chronic disseminated candidiasis from 19 countries, diagnosed between January 2007 and December 2025. The condition, also known as hepatosplenic candidiasis, typically strikes patients with blood cancers such as acute myeloid leukaemia as their white blood cell counts recover after prolonged chemotherapy-induced neutropenia. It produces persistent fever, abdominal pain, cholestasis and characteristic abscesses in the liver and spleen, and it can force delays in cancer treatment that may ultimately matter more than the infection itself.</p>
<p>Almost all patients in the cohort had an underlying haematological malignancy. Acute myeloid leukaemia accounted for 48.6 percent of cases and acute lymphoblastic leukaemia for 24.7 percent, with lymphoma making up a further 15.6 percent. Notably, 24.8 percent of patients developed the infection despite receiving systemic antifungal prophylaxis in the days before diagnosis, so-called breakthrough disease, a figure that underscores the limits of current preventive strategies in the era of widespread mould-active azole prophylaxis.</p>
<p>The researchers applied a sophisticated statistical approach rarely used in this field: marginal structural models with inverse probability of treatment weighting, designed to account for time-varying confounders such as neutropenia and corticosteroid exposure that shift over the course of illness and can distort simple treatment comparisons. After this adjustment, neither the class of first-line antifungal, whether echinocandins, liposomal amphotericin B or azoles, nor the choice between fluconazole and other azoles for long-term oral step-down therapy was significantly associated with treatment response or overall survival.</p>
<p>This is a striking result given that international guidelines currently recommend echinocandins or liposomal amphotericin B as initial therapy, followed by an oral azole. Echinocandins were indeed the most common first-line choice in the cohort, used in 58.6 percent of patients, reflecting alignment with contemporary guidance. But the new data suggest clinicians may have greater flexibility than guidelines imply, particularly for patients with prior azole exposure or resistant organisms, where alternatives to fluconazole have previously rested on thin evidence.</p>
<p>Perhaps the most practice-changing observation concerns treatment duration. The median total course of targeted antifungal therapy was 107 days, substantially shorter than the four to seven months reported in earlier cohorts, and no relapses were documented after treatment was stopped during a median post-discontinuation follow-up of 92 days. Because conventional CT abnormalities can persist for many months after the infection has been controlled, with resolution rates of only 30 to 34 percent at three months in prior studies, the findings support the idea that extending therapy until complete radiological resolution may be unnecessary in selected patients.</p>
<p>Advanced imaging may hold the key to individualising that decision. Positron emission tomography combined with CT was performed in 26.1 percent of patients, and in 12 of them, regression of PET/CT findings was explicitly cited as the reason for stopping antifungal therapy. These patients had markedly longer treatment courses than those without PET-guided decisions, a median of 219 versus 88 days. The results complement the earlier French CANHPARI pilot study, which suggested that PET/CT normalisation at three months may better reflect resolution of active inflammation than conventional imaging, and they point toward PET/CT-guided assessment as a promising tool for distinguishing residual infection from immune reconstitution inflammatory syndrome, the paradoxical worsening that occurs as neutrophils recover.</p>
<p>The study also documented under-recognised manifestations of the disease. Nine patients showed central nervous system involvement, with multifocal punctate or ring-enhancing lesions on neuroimaging and, in some cases, positive cerebrospinal fluid beta-D-glucan testing. Skin and soft tissue involvement occurred in nine patients, six of whom had Candida tropicalis infection, a species known for cutaneous dissemination. The authors suggest that clinicians should consider CNS imaging in patients with neurological symptoms or refractory disease, since cerebral spread may be more common than previously appreciated.</p>
<p>Microbiological findings carried their own geographic and therapeutic signals. Candida albicans accounted for 32.4 percent of identified isolates and C. tropicalis for 24.3 percent, with the latter clustering markedly in Taiwan and Colombia. Fluconazole resistance was found in 11 isolates and was far more frequent in C. tropicalis than in other species, affecting 29.6 percent versus 3.6 percent, and nearly two-thirds of resistant cases occurred in the context of breakthrough infection. Yet resistance did not translate into worse survival, and beta-D-glucan, a fungal cell-wall marker measured at baseline in 35 patients, was positive in 88.6 percent, suggesting it may serve as a useful diagnostic adjunct.</p>
<p>Ultimately, the numbers tell a story about host biology rather than pharmacology. Only 4.5 percent of deaths were attributable to the fungal infection itself, even though all-cause mortality reached 33.3 percent, and patients with breakthrough disease actually survived more often than those without, likely because their underlying cancers were in a more favourable state. The authors caution that their comparative treatment analyses were exploratory and not powered to exclude clinically meaningful differences, and they call for prospective studies incorporating immune biomarkers such as cytokine profiles and Candida-specific T-cell responses alongside PET/CT. But for a disease that has been managed largely by tradition and caution, the message is clear: immune recovery, not drug selection, may be the true engine of cure, and shorter, individually tailored treatment could spare vulnerable patients months of toxicity, cost and delayed cancer therapy.</p>
<p><strong>Subject of Research:</strong> Treatment strategies and outcomes of chronic disseminated candidiasis in patients with haematological malignancies in the era of antifungal prophylaxis</p>
<p><strong>Article Title:</strong> Treatment and outcome of chronic disseminated candidiasis in the era of antifungal prophylaxis: a retrospective multicentre cohort of 111 patients</p>
<p><strong>Article References:</strong> Reinhold, I., Ramirez-Sanchez, I. C., Chen, P.-Y., Chen, Y.-C., Dhariwal, A., Lambourne, J., Agrawal, S., Bastida, M., Gudiol, C., Alfandari, S., Di Pilla, A., Khostelidi, S., Aguilar-Zapata, D., Barac, A., Cipriano, A., Ehrlich, S., Grothe, J., Illarramendi, J., Jennrich, S., &#8230; Zager, L. (2026). Treatment and outcome of chronic disseminated candidiasis in the era of antifungal prophylaxis: a retrospective multicentre cohort of 111 patients. <em>eClinicalMedicine, 100</em>, Article 104194. <a href="https://doi.org/10.1016/j.eclinm.2026.104194" rel="noopener noreferrer">https://doi.org/10.1016/j.eclinm.2026.104194</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1016/j.eclinm.2026.104194" rel="noopener noreferrer">10.1016/j.eclinm.2026.104194</a></p>
<p><strong>Keywords:</strong> chronic disseminated candidiasis, hepatosplenic candidiasis, haematological malignancies, antifungal therapy, echinocandins, azoles, Candida tropicalis, fluconazole resistance, PET/CT imaging, immune reconstitution, neutropenia, beta-D-glucan</p>
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		<post-id xmlns="com-wordpress:feed-additions:1">212739</post-id>	</item>
		<item>
		<title>PET Imaging Reveals Whether Immunotherapy Drugs Actually Reach Their Tumour Targets</title>
		<link>https://scienmag.com/pet-imaging-reveals-whether-immunotherapy-drugs-actually-reach-their-tumour-targets/</link>
		
		<dc:creator><![CDATA[Nathaniel Bowman]]></dc:creator>
		<pubDate>Sat, 12 Sep 2026 15:04:52 +0000</pubDate>
				<category><![CDATA[Cancer]]></category>
		<category><![CDATA[assessing immunotherapy efficacy]]></category>
		<category><![CDATA[atezolizumab]]></category>
		<category><![CDATA[atezolizumab and PD-L1 binding]]></category>
		<category><![CDATA[biomarker limitations in immunotherapy]]></category>
		<category><![CDATA[British Journal of Cancer]]></category>
		<category><![CDATA[checkpoint inhibitors]]></category>
		<category><![CDATA[immune checkpoint inhibitors]]></category>
		<category><![CDATA[Immunotherapy]]></category>
		<category><![CDATA[Immunotherapy Monitoring]]></category>
		<category><![CDATA[molecular imaging]]></category>
		<category><![CDATA[non-invasive cancer imaging techniques]]></category>
		<category><![CDATA[PD-L1]]></category>
		<category><![CDATA[personalized immunotherapy strategies]]></category>
		<category><![CDATA[PET/CT imaging]]></category>
		<category><![CDATA[PET/CT imaging in cancer treatment]]></category>
		<category><![CDATA[pharmacodynamics]]></category>
		<category><![CDATA[precision oncology]]></category>
		<category><![CDATA[radiotracer]]></category>
		<category><![CDATA[real-time cancer treatment assessment]]></category>
		<category><![CDATA[receptor saturation in cancer therapy]]></category>
		<category><![CDATA[target saturation]]></category>
		<category><![CDATA[tumor drug delivery challenges]]></category>
		<category><![CDATA[tumor target visualization]]></category>
		<category><![CDATA[tumour microenvironment]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=195663</guid>

					<description><![CDATA[Researchers are using PD-L1-targeted PET/CT imaging to directly visualise whether the immunotherapy drug atezolizumab saturates its target in tumours, offering a real-time alternative to delayed response assessment.]]></description>
										<content:encoded><![CDATA[<p>Immune checkpoint inhibitors have transformed the treatment landscape for many cancers, yet a stubborn problem continues to shadow their clinical use: most patients do not respond, and clinicians have had no reliable way to know in advance who will benefit. A study published in the British Journal of Cancer explores a solution that could change how immunotherapy is monitored in real time. Rather than relying on tumour biopsies or static biomarker tests, researchers investigated whether positron emission tomography combined with computed tomography, known as PET/CT, could visualise precisely how much of the checkpoint inhibitor atezolizumab binds to its molecular target, programmed death ligand 1, inside tumours during treatment.</p>
<p>The central concept behind the research is receptor saturation. Atezolizumab is a monoclonal antibody designed to bind PD-L1, a protein that many tumours deploy on their surfaces to suppress the immune cells that would otherwise attack them. By occupying PD-L1, atezolizumab blocks this molecular camouflage and releases the brakes on the immune system. But the drug can only work where it actually reaches the target in sufficient quantity. If a tumour expresses abundant PD-L1 but has poor blood supply, dense stromal barriers, or unfavourable pharmacokinetics, the antibody may fail to saturate the target even though the patient receives a full therapeutic dose. Conventional testing, which involves staining a biopsy sample for PD-L1 expression, captures only a snapshot of a tiny fragment of the tumour at a single moment in time and says nothing about whether the drug is engaging its target throughout the body.</p>
<p>PET imaging offers a fundamentally different perspective. In the approach examined by the researchers, atezolizumab is labelled with a radioactive tracer, typically the radionuclide zirconium-89, whose decay signature can be detected by the PET scanner. When the labelled antibody is injected into a patient, the scanner produces three-dimensional maps showing exactly where the drug accumulates. If a tumour lights up with signal before treatment, it indicates that PD-L1 is present and accessible to the antibody. If the signal diminishes or disappears after the patient begins therapy with unlabelled atezolizumab, it indicates that the therapeutic antibody has flooded the target sites, occupying them so thoroughly that the labelled tracer can no longer bind. This drop in tracer uptake is the imaging signature of target saturation, the pharmacodynamic state in which the drug is doing its intended molecular job at the tumour site.</p>
<p>The logic of this imaging paradigm rests on a simple competitive principle. Before treatment begins, when no therapeutic antibody is circulating, the radiolabelled atezolizumab analogue can bind freely to PD-L1 molecules on tumour cells, producing strong PET signal. Once a patient starts standard atezolizumab infusions, the circulating therapeutic antibody competes with the tracer for the same binding sites. As the drug concentration rises and saturates available PD-L1, tracer uptake falls. The degree of that fall provides a direct, whole-body measure of how completely the treatment is engaging its target in each tumour lesion. This is often described as an in vivo pharmacodynamic biopsy: instead of sampling one lesion surgically, clinicians can observe drug-target interactions across every detectable tumour deposit simultaneously, including metastases in locations that could never be biopsied safely.</p>
<p>The significance of this capability becomes clear when considering how immunotherapy is currently managed. Patients with non-small cell lung cancer, bladder cancer, and other PD-L1-positive malignancies typically receive atezolizumab or similar agents on fixed schedules, often for months, before standard imaging can reveal whether the tumours are shrinking. Response assessment by CT generally takes weeks to months to show meaningful change, because tumour shrinkage is a delayed downstream consequence of immune activation. Target saturation, by contrast, is an immediate upstream event. If imaging shows that the antibody has fully occupied PD-L1 within days of the first dose, and the tumour still fails to respond over the following months, the problem lies elsewhere: the tumour may have developed alternative immune-evasion mechanisms, the tumour microenvironment may lack infiltrating T cells, or downstream signalling may be blocked. Distinguishing pharmacokinetic failure, where the drug never reached the target, from biological resistance, where the drug engaged the target but the cancer resisted anyway, is exactly the information that saturation imaging is designed to provide.</p>
<p>Past work in this field has demonstrated the technical feasibility of the approach. Radiolabelled versions of atezolizumab and the related antibody pembrolizumab have been used in early-phase clinical trials, showing that PD-L1-specific PET signal can be detected in human tumours, that uptake varies widely between patients, and that heterogeneity exists even among different metastatic lesions within the same individual. These studies revealed something that biopsies had long obscured: a patient whose primary tumour shows strong PD-L1 staining may harbour liver metastases with negligible target expression, and those lesions may behave very differently under treatment. Quantitative measures derived from PET scans, such as standardised uptake values, have been correlated with clinical outcomes in preliminary analyses, hinting that baseline tracer uptake and early changes during therapy could serve as predictive biomarkers in their own right.</p>
<p>Dosing is another area where saturation imaging carries substantial implications. Current atezolizumab regimens were established through trials that sought doses safely exceeding the levels needed for receptor occupancy, but those occupancy estimates were largely derived from circulating drug levels and receptor occupancy measurements on peripheral blood cells, not from direct measurements inside tumours. Tumour penetration is governed by different physics: antibody extravasation through leaky but uneven vasculature, diffusion through the extracellular matrix, binding-site barriers created by dense target expression near blood vessels, and clearance rates that vary with tumour type and location. PET saturation imaging brings these hidden variables into view. A tumour that retains strong tracer uptake even after multiple treatment doses is telling clinicians that the target remains unsaturated, suggesting that dose escalation, altered scheduling, or combination strategies that improve drug delivery might be worth considering for that specific patient.</p>
<p>The study published in the British Journal of Cancer contributes to this evolving evidence base by evaluating PD-L1 PET/CT specifically as a tool to assess tumour saturation during atezolizumab treatment. The broader research programme of which it forms a part reflects a decisive shift in oncology drug development: away from one-size-fits-all dosing and toward imaging-verified pharmacodynamics. Regulatory science has begun to take note. Methods that demonstrate target engagement early in treatment could accelerate clinical trials by providing early surrogate indicators, reducing the sample sizes and follow-up durations needed to establish whether a drug regimen is mechanistically active. They could also support adaptive treatment strategies in routine care, in which imaging results after the first one or two doses inform whether the patient should continue, switch, or intensify therapy long before tumour volume changes would be visible.</p>
<p>Challenges remain before such imaging can enter routine practice. Radiolabelling antibodies with zirconium-89 requires cyclotron facilities, radiochemistry expertise, and regulatory compliance that currently limits availability to specialised centres. The half-life of zirconium-89, roughly 78 hours, suits the slow pharmacokinetics of antibodies, which circulate for days to weeks before reaching peak tumour uptake, but it also means patients must return for scans several days after injection and absorb a meaningful radiation dose. Cost, reimbursement, and the need for standardised scanning protocols and uptake thresholds all stand between promising trial results and clinical adoption. Questions also persist about how best to interpret partial saturation, how tracer signal in the liver and spleen, organs with high background antibody uptake, affects quantification of abdominal lesions, and how the immune response triggered by treatment itself alters target expression over time.</p>
<p>Nevertheless, the trajectory of the field is unmistakable. Molecular imaging of drug-target engagement is converging with immunotherapy at a moment when the limitations of current biomarkers have become painfully evident. PD-L1 immunohistochemistry, tumour mutational burden, and gene-expression signatures each capture only a fragment of the biology that determines whether a patient responds to checkpoint blockade. Saturation imaging promises something those tools cannot: a dynamic, whole-body, patient-specific readout of whether the drug is doing, at the molecular level, what it was designed to do. If validated in larger cohorts, the approach exemplified by this line of research could move immunotherapy closer to the ideal of precision medicine, where the first weeks of treatment generate actionable information rather than a waiting period measured in months. For the many patients whose tumours do not respond to atezolizumab and its peers, that shift could mean less time on ineffective therapy, faster transitions to alternatives, and a clearer mechanistic understanding of why immunotherapy succeeds or fails in each individual.</p>
<p><strong>Subject of Research:</strong> PD-L1 PET/CT molecular imaging to assess tumour target saturation during atezolizumab immunotherapy</p>
<p><strong>Article Title:</strong> Programmed death ligand 1 (PD-L1) PET/CT imaging to evaluate tumour saturation during atezolizumab treatment</p>
<p><strong>Article References:</strong> Hooiveld-Noeken, J. S., van de Donk, P. P., Kist de Ruijter, L., Kok, I. C., van Winkel, C. A. J., Giesen, D., Lub-de Hooge, M. N., Brouwers, A. H., Oosting, S. F., Bensch, F., Smit, L. M., Schröder, C. P., Jalving, M., Elias, S. G., Gietema, J. A., Deurloo, R. J., Williams, S. P., Ungewickell, A., de Groot, D.-J. A., &amp; de Vries, E. G. E. (2026). Programmed death ligand 1 (PD-L1) PET/CT imaging to evaluate tumour saturation during atezolizumab treatment. <em>British Journal of Cancer</em>. <a href="https://doi.org/10.1038/s41416-026-03595-8" rel="noopener noreferrer">https://doi.org/10.1038/s41416-026-03595-8</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1038/s41416-026-03595-8" rel="noopener noreferrer">10.1038/s41416-026-03595-8</a></p>
<p><strong>Keywords:</strong> PD-L1, PET/CT imaging, atezolizumab, immunotherapy, checkpoint inhibitors, target saturation, molecular imaging, radiotracer, tumour microenvironment, pharmacodynamics, precision oncology, British Journal of Cancer</p>
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