The prostate is not just a bag of secretory cells. It is a composite tissue in which a fibromuscular stroma, packed with collagen, elastic fibers, smooth muscle, blood vessels, nerves and immune cells, wraps around and actively regulates the glandular epithelium. When that stroma stiffens with excess collagen, a process called fibrosis, the epithelial cells above it can lose their normal growth controls, a shift implicated in benign prostatic hyperplasia and in the reactive stroma that surrounds prostate tumors. Prostate cancer remains one of the most common malignancies worldwide, with roughly 1.4 million new cases recorded in 2020, making any strategy that softens or reorganizes the stromal matrix of considerable clinical interest.

Mycophenolate mofetil was developed to block lymphocyte proliferation after transplantation. Once in the body it is hydrolyzed into mycophenolic acid, a potent, selective and reversible inhibitor of inosine monophosphate dehydrogenase, an enzyme essential to the de novo synthesis of guanosine nucleotides. Lymphocytes depend heavily on this pathway, which is why the drug works as an immunosuppressant. But fibroblasts rely on the same guanosine-dependent machinery to proliferate, migrate and adhere, and mycophenolic acid also downregulates cytoskeletal proteins such as vinculin, actin and tubulin while cutting collagen output and boosting matrix metalloproteinase expression. The result, the researchers reasoned, could be a pharmacologically induced softening of fibrotic tissue, and the rat prostate offered an ideal, hormone-sensitive testing ground.

The team, led by Luiz Roberto Falleiros Junior of São Paulo State University and collaborators at the Federal University of Goiás, UNICAMP and the Faculty of Medicine of São José do Rio Preto, gave adult male Wistar rats 30 milligrams per kilogram of the drug daily by gavage for either 7 or 30 days, with a saline-treated control group for comparison. They then subjected the ventral prostate to an unusually thorough battery of analyses: stereological point counting to quantify each tissue compartment, histochemical stains for collagen I, collagen III and elastic fibers, polarization microscopy to assess collagen aggregation, and immunohistochemistry for matrix metalloproteinases 2 and 13, the inhibitor TIMP-1, the androgen receptor, both estrogen receptors, proliferation and apoptosis markers, smooth muscle actin and macrophages. Mast cells were counted with toluidine blue, and lesions were graded using standard rodent prostate pathology criteria.

The first phase of remodeling emerged within a week. After just 7 days of treatment, the area occupied by collagen III, the thin reticular fibers that form a supportive network beneath the epithelium, had dropped significantly, and elastin fibers had diminished as well. This early matrix disassembly coincided with a marked rise in matrix metalloproteinase 2, an enzyme expressed in the non-muscular stroma that not only degrades basement membrane components but also activates other, more aggressive MMPs in the stromal cascade and participates in elastolysis. Because collagen III helps anchor and polarize epithelial cells, its loss had immediate consequences upstairs: epithelial cells showed reduced androgen receptor expression, less proliferation as measured by phosphohistone H3, and more apoptosis, revealed by activated caspase-3, in both the epithelium and the stroma.

The second phase unfolded over the following weeks. By 30 days, the drug had turned its attention to collagen I, the thick, highly birefringent fiber type that organizes stromal cells and orients the smooth muscle layer. Polarization microscopy showed reduced collagen aggregation, indicating a softer extracellular matrix, and this breakdown tracked with a surge in matrix metalloproteinase 13, or collagenase 3, detected in luminal epithelial cells and in the smooth muscle layer. At the same time the muscular stroma thinned, the non-muscular stroma expanded, and blood vessel density increased, a pattern consistent with matrix softening and with MMP-13’s known association with angiogenesis. Notably, TIMP-1, the natural brake on the metalloproteinases, showed no significant change at either time point, leaving the remodeling enzymes essentially unchecked.

The immune system turned out to be a scheduled participant rather than a bystander. Degranulated mast cells, which release their own matrix-degrading enzymes when they discharge their granules, rose early and remained elevated through 30 days, while intact mast cells plummeted. Macrophages, identified by the F4/80 marker, increased only at the later time point and formed clusters in the periglandular stroma of treated animals, alongside a rise in inflammatory foci. The authors interpret this sequence as successive waves of immune involvement: mast cells kick off extracellular matrix degradation, and macrophages arrive later to phagocytose the debris and clear the way for tissue reorganization. Inflammatory cells also stained positive for TIMP-1, hinting at a more complex regulatory dialogue than the simple enzyme-inhibitor balance alone.

Perhaps the most provocative finding concerns the androgen axis. Androgen receptor levels in the epithelium fell sharply at both time points, and the incidence of high-grade prostatic intraepithelial neoplasia, a precancerous lesion that depends on androgen signaling, dropped at 30 days, while simple hyperplasia increased. The authors propose a mechanistic explanation drawn from prior work: mycophenolic acid activates the aryl hydrocarbon receptor, which interferes with androgen receptor transcription, and it also impairs androgen receptor phosphorylation through the MAPK8/9 pathway, blocking the nuclear translocation the receptor needs to function. The researchers are careful to note that their two-endpoint design cannot establish causality, and that the rise in hyperplasia shows the drug did not restore normal glandular homeostasis but rather redirected the epithelium toward a proliferative pattern lacking pre-neoplastic features.

The study’s authors go further, proposing that the compartment-specific measurements they tracked, including the collagen I to III ratio, MMP2 and MMP13 immunolabeling, smooth muscle area and microvascular density, could serve as pharmacodynamic readouts of antifibrotic efficacy in future studies, much as circulating collagen turnover markers have been used to identify responders in other fibroproliferative diseases. They also raise, explicitly as an untested hypothesis, the possibility that antifibrotic interventions like mycophenolate mofetil could restrain androgen-dependent lesions in conditions such as benign prostatic hyperplasia. Validating that idea, they caution, would require established hyperplasia models, dose-response protocols, intermediate time points, paired tissue and serum measurements, long-term follow-up, and a careful weighing of the systemic immunosuppression the drug inevitably causes. Biometric data offered reassurance in the short term, with no differences in body or prostate weight between treated and control animals.

What makes the study resonate beyond urology is its demonstration that a stroma-targeted drug reached the epithelium through hormone signaling, placing fibrotic status and androgen responsiveness on connected axes of prostatic homeostasis. If the two remodeling windows the team identified hold up in larger and longer studies, clinicians may one day time antifibrotic therapy against measurable tissue benchmarks rather than trial and error, and the humble immunosuppressant in every transplant pharmacy may find a second career as a precision instrument for softening the scarred landscapes where prostate disease takes root.

Subject of Research: Antifibrotic effects of mycophenolate mofetil on stromal remodeling and collagen dynamics in the rat prostate

Article Title: Stromal Remodeling and Collagen Dynamics under Antifibrotic Conditions in the Rat Prostate

Article References: Falleiros Junior, L. R., Ruiz, T. F. R., Grigio, V., Bicalho-Silva, S., Colleta, S. J., de Souza, L. G., Ferrato, L. J., Vilamaior, P. S. L., da Silveira Antoniassi, T., Spessoto, L. C. F., Taboga, S. R., & Facio Junior, F. N. (2026). Stromal Remodeling and Collagen Dynamics under Antifibrotic Conditions in the Rat Prostate. Reproductive Sciences. https://doi.org/10.1007/s43032-026-02221-5

Image Credits: AI Generated

DOI: 10.1007/s43032-026-02221-5

Keywords: mycophenolate mofetil, prostate, fibrosis, collagen, matrix metalloproteinases, stroma, androgen receptor, mast cells, macrophages, extracellular matrix, rat model, antifibrotic therapy

The patient arrived with intrahepatic cholangiocarcinoma, an aggressive cancer of the bile ducts within the liver, and received two doses of immune checkpoint inhibitor therapy. Shortly afterward, her blood tests revealed a striking pattern of myocardial injury. Cardiac troponin T, a protein released when heart muscle cells die, climbed to 0.263 nanograms per milliliter, nearly nineteen times the upper limit of the normal range of less than 0.014. Creatine kinase reached 647 units per liter against a normal ceiling of 140, the myocardial band fraction of that enzyme hit 38 units per liter where the normal range tops out at 23, and myoglobin surged to 515 nanograms per milliliter, far above the normal maximum of 58. Yet paradoxically, her initial electrocardiogram showed no arrhythmia, her echocardiogram was unremarkable, and her left ventricular ejection fraction stood at a healthy 65 percent. Coronary computed tomography revealed only mild stenosis, and cardiac magnetic resonance imaging came back negative.

This disconnect between laboratory evidence of heart injury and reassuring imaging is precisely what makes immune checkpoint inhibitor-associated myocarditis, abbreviated ICIAM, so treacherous. After a multidisciplinary team discussion excluded alternatives such as viral myocarditis and significant coronary artery disease, the clinicians diagnosed ICIAM based on the temporal relationship to immunotherapy and the characteristic biomarker profile. The team immediately suspended all anti-tumor treatment and began intravenous methylprednisolone at 2 milligrams per kilogram of body weight, 120 milligrams per day for three days, the first-line therapy recommended by the European Society of Cardiology guidelines on cardio-oncology. In many patients, high-dose corticosteroids rapidly suppress the aberrant immune attack, and troponin levels fall. In this patient, they did not.

During steroid therapy, her troponin T declined only marginally, from 0.263 to 0.187 nanograms per milliliter, a drop far short of the 50 percent reduction from peak that defines a steroid-responsive case. This failure established the diagnosis of steroid-resistant ICIAM, a subset of the condition associated with a grim prognosis and, until recently, no established effective therapy. The reported mortality of ICIAM overall ranges from 39.7 to 66 percent, and steroid-resistant cases fare worst of all. Recognizing the stakes, the team added tofacitinib, a Janus kinase inhibitor that blocks intracellular signaling pathways used by pro-inflammatory cytokines, at a dose of 5 milligrams twice daily. The hope was that shutting down JAK-mediated cytokine signaling would break the immune assault on the myocardium that steroids alone could not extinguish.

Instead, the disease escalated. Troponin levels rose further, and a new electrocardiographic abnormality emerged: frequent premature ventricular contractions, extra heartbeats originating in the ventricles that signal electrical instability of the heart muscle. In the context of ongoing myocarditis, such arrhythmias can presage malignant rhythms and sudden cardiac death. The clinicians now faced a patient whose heart inflammation was resisting both the standard of care and the first escalation. Drawing on their center’s prior experience and on the ratio of CD4 to CD8 lymphocytes in the patient’s peripheral blood mononuclear cells, which stood at 3.1 against a normal range of 0.6 to 2.9 and pointed to a skewed immune activation state, they added mycophenolate mofetil, an inhibitor of guanine nucleotide synthesis that suppresses lymphocyte proliferation, at 7.5 grams twice daily, combined with intravenous immunoglobulin at 10 grams per day for five days as intensive immunosuppressive therapy.

The response was decisive. Troponin T levels began a gradual, sustained decline, and the ventricular arrhythmia resolved, with follow-up electrocardiograms returning to normal. The patient achieved complete remission of the myocarditis, and, critically, her anti-tumor treatment was successfully rechallenged once the cardiac complication was stably controlled. That final step matters enormously in clinical practice. Myocarditis forces clinicians to stop the very drugs controlling a patient’s cancer, and permanent discontinuation can leave an aggressive malignancy unchecked. Demonstrating that the myocarditis can be brought under control and immunotherapy resumed converts a life-threatening side effect from an automatic end of treatment into a manageable detour.

The mechanistic backdrop helps explain why this case unfolded as it did. Immune checkpoint inhibitors block inhibitory receptors such as PD-1 and CTLA-4, releasing brakes on T cells so they can attack tumors. In susceptible individuals, that release of restraint extends to self-reactive immune clones, and the heart becomes a target. Research, including a 2024 study in Nature that mapped immune responses across the heart, blood, and tumor in checkpoint myocarditis, shows infiltration of the myocardium by activated immune cells and a storm of pro-inflammatory cytokines. High-risk populations include patients receiving combination immunotherapy, whether dual checkpoint inhibitors or checkpoint inhibitors paired with chemotherapy or anti-angiogenic agents, and those with diabetes, pre-existing cardiovascular disease, higher body mass index, or advanced age. This patient, at 77 with cholangiocarcinoma, fit squarely within the vulnerable demographic.

The therapeutic landscape for steroid-resistant disease remains unsettled, which is what makes documented cases so valuable. Several agents are under investigation as second-line options: tofacitinib and its fellow JAK inhibitor baricitinib, which animal and early clinical work suggests protects the myocardium by targeting JAK1/STAT3 signaling to modulate macrophage polarization; mycophenolate mofetil; anti-thymocyte globulin, an antibody that depletes T cells; intravenous immunoglobulin; tocilizumab, an interleukin-6 receptor blocker; abatacept, a CTLA-4 agonist that restores inhibitory signaling to T cells; alemtuzumab, an anti-CD52 antibody; and plasma exchange. European Society of Cardiology guidelines recommend considering second-line immunosuppression when steroids fail, but they stop short of endorsing any specific regimen, instead recommending multidisciplinary team discussion. The Shanghai group notes that in their center, tofacitinib has provided clinical benefit when used early in steroid-resistant patients, though some patients resist it, and mycophenolate mofetil has shown potential benefit in exactly those situations, as this case illustrates.

The sequencing in this patient carries the report’s central lesson. Tofacitinib alone, added on top of methylprednisolone, did not halt the injury; troponin continued to climb and arrhythmias appeared. Only with the addition of mycophenolate mofetil, guided by the abnormal CD4-to-CD8 ratio, did the inflammatory cascade collapse. The authors interpret this as evidence that early administration of second-line immunosuppressive therapy, tailored and intensified rather than delayed, is crucial for good outcomes in steroid-resistant ICIAM. The phrase early administration recurs throughout their discussion because the window is narrow: myocarditis driven by unleashed T cells can progress from biomarker elevation to fatal arrhythmia within days, and median onset of the condition falls between 17 and 65 days after starting immunotherapy, meaning the danger period spans the very weeks when patients and clinicians are most optimistic about the cancer treatment itself.

For the growing population of patients receiving checkpoint inhibitors worldwide, this case is a reminder that the revolution in cancer immunotherapy carries a cardiac shadow that demands vigilance. Troponin monitoring after immunotherapy initiation, a low threshold for multidisciplinary consultation, and readiness to escalate beyond steroids within days rather than weeks form the practical take-home framework. No single case can establish which second-line regimen is superior, and the authors themselves emphasize the current lack of data to recommend one specific protocol. But by documenting a complete remission achieved with tofacitinib, mycophenolate mofetil, and immunoglobulin, followed by a safe return to anti-cancer therapy, the Zhongshan Hospital team has added a concrete, clinically actionable data point to a field where every documented survival matters. As immunotherapy expands to more tumor types and earlier disease stages, the number of patients exposed to this rare but lethal risk will only grow, and the accumulated experience of cases like this one will shape the guidelines that keep them alive.

Subject of Research: Steroid-resistant myocarditis caused by immune checkpoint inhibitor cancer therapy and its treatment with second-line immunosuppressive drugs

Article Title: Steroid-resistant immune checkpoint inhibitor-associated myocarditis: a case report

Article References: He, X., Zhang, Y., Wang, Y., Chen, H., Liu, Y., & Cheng, L. (2025). Steroid-resistant immune checkpoint inhibitor-associated myocarditis: a case report. Clinical Cancer Bulletin, 4(1), Article 5. https://doi.org/10.1007/s44272-025-00033-3

Image Credits: AI Generated

DOI: 10.1007/s44272-025-00033-3

Keywords: immune checkpoint inhibitors, myocarditis, immunotherapy, troponin, tofacitinib, mycophenolate mofetil, cardiotoxicity, immunosuppression, cholangiocarcinoma, steroid resistance, arrhythmia, cardio-oncology

NMOSD is a rare, autoimmune inflammatory disorder of the central nervous system that predominantly targets the optic nerves and spinal cord. In most patients, the disease is driven by pathogenic immunoglobulin G antibodies directed against aquaporin-4 (AQP4), a water channel protein abundantly expressed on astrocytes. Each relapse can leave permanent neurological damage, ranging from irreversible vision loss to paralysis, which is why suppressing the underlying B-cell–driven immune attack is the central goal of long-term management. Before targeted therapies earned regulatory approval, clinicians commonly prescribed oral immunosuppressants (ISTs) such as azathioprine, mycophenolate mofetil, and methotrexate off-label to keep the disease at bay.

Those older drugs have well-recognized shortcomings. Comparative studies have associated oral ISTs with a greater frequency of relapses and a shorter time to relapse after treatment initiation compared with approved monoclonal antibodies. They are also linked to gastrointestinal and hematologic side effects and a high frequency of infections, problems that accumulate over years of continuous use. Inebilizumab, by contrast, is a humanized, affinity-optimized, glycoengineered monoclonal antibody that targets CD19, a marker expressed broadly across the B-cell lineage, depleting the cells responsible for producing the pathogenic AQP4 antibodies. The randomized, placebo-controlled N-MOmentum trial demonstrated its efficacy in AQP4-seropositive NMOSD and led to regulatory approval.

A key question remained, however. Many participants entering N-MOmentum had years of prior IST exposure, and it was unclear whether that treatment history might blunt or otherwise alter the drug’s long-term efficacy and safety. To investigate, researchers analyzed 202 of the 213 AQP4-seropositive participants from the randomized controlled period (RCP) and 197 of the 201 from the open-label period (OLP), splitting them roughly evenly between those with prior IST treatment and those who were IST-naïve. Only ISTs taken before day 1 of the trial were considered; ISTs were prohibited once the trial began.

The randomized portion of the trial delivered an unambiguous message. Participants on inebilizumab experienced far fewer adjudicated NMOSD attacks than those on placebo, and the magnitude of benefit was essentially identical in both subgroups. Among participants with prior IST use, the hazard ratio for attack was 0.21 (95% confidence interval 0.09–0.48), while among IST-naïve participants it was 0.23 (0.09–0.59). NMOSD-related inpatient hospitalizations were also less frequent with inebilizumab in the prior-IST group. Worsening on the Expanded Disability Status Scale (EDSS) was significantly less common with inebilizumab versus placebo in both groups: 19.2% versus 43.5% among those with prior IST exposure, and 13.6% versus 28.0% among those who were IST-naïve, both comparisons reaching nominal statistical significance.

Because the randomized controlled period lasted only about 28 weeks, the research team turned to modeling to assess long-term outcomes over years rather than months. In the any-INEB population, the adjusted annualized attack rate was 0.11 (0.07–0.17) for participants with prior IST use and 0.08 (0.05–0.14) for those without, a difference so small it is unlikely to matter clinically. A high probability of remaining attack-free persisted through week 286 of treatment in both groups, and EDSS scores actually improved during the open-label extension regardless of treatment history. NMOSD-related hospitalizations were equal in number across the two subgroups during long-term follow-up.

The most striking results emerged when inebilizumab was compared against synthetic historical comparator groups built from published Kaplan–Meier survival curves of patients treated with azathioprine or other broad-spectrum ISTs, or with placebo. Using a time-varying spline model with two internal knots, selected through formal information-criterion testing and visual fit assessment, the researchers found the time to NMOSD attack was significantly longer with inebilizumab than with azathioprine or other ISTs (hazard ratio 0.29; p < 0.001) and than with placebo (hazard ratio 0.15; p < 0.001). The modeled four-year attack-free probability was 77% for inebilizumab, 36% for azathioprine or other ISTs, and just 12% for placebo. Notably, the widening gap over time suggests inebilizumab’s relative advantage may grow the longer patients stay on treatment.

Safety outcomes were reassuringly similar across subgroups. Through the open-label period, roughly 92% of participants in both groups experienced at least one treatment-emergent adverse event, but drug-related events were somewhat more common among IST-naïve participants, 46.6% versus 30.9%. Infections, the adverse event category of greatest concern for a B-cell–depleting therapy, occurred at nearly identical rates in both groups, affecting 72.3% of those with prior IST use and 76.7% of those without, and were not increased by prior immunosuppressant exposure. Opportunistic infections were rare, one case in each group, no anaphylactic reactions were reported, and deaths were similarly uncommon.

The authors caution that this was a post hoc, exploratory analysis with limitations. Subgroup sample sizes were modest, randomization was not stratified by duration of IST history, and p values were not adjusted for multiple comparisons, so all statistical results are nominal. The synthetic historical comparators, reconstructed by digitizing published survival curves, introduce approximation error and cannot fully control for differences in study populations and designs across the source studies. These constraints mean the long-term comparative estimates should be interpreted as suggestive rather than definitive evidence from head-to-head trials, which have never been conducted.

Even so, the practical implications for patients and clinicians are substantial. Switching from off-label immunosuppressants to immunotherapies generally requires an overlapping treatment period to avoid triggering an attack upon discontinuation of the old drug, and many providers overlap ISTs for up to six months, although concurrent inebilizumab and IST use is not recommended as a routine regimen. The new analysis supports inebilizumab treatment for patients with AQP4-seropositive NMOSD regardless of whether they previously received first-line immunosuppressants, with sustained reductions in attack risk, stabilized or improved disability scores, and a safety profile consistent with the overall trial population. For the many patients still managed with older oral agents, the data offer a quantitative basis for a confident transition to targeted B-cell depletion.

Subject of Research: Long-term efficacy and safety of inebilizumab in AQP4-seropositive NMOSD patients with or without prior immunosuppressant use

Article Title: Efficacy of Inebilizumab in N‐MOmentum Trial Participants With or Without Prior Immunosuppressants

Article References: Cree, B. A. C., Suero, B., Walsh, S., Marignier, R., Lindsey, J. W., Kim, H. J., She, D., Cimbora, D., Cavida, D., & Paul, F. (2026). Efficacy of Inebilizumab in N‐ MOmentum Trial Participants With or Without Prior Immunosuppressants. Annals of Clinical and Translational Neurology, 13(9), 1930-1936. https://doi.org/10.1002/acn3.70426

Image Credits: AI Generated

DOI: 10.1002/acn3.70426

Keywords: inebilizumab, NMOSD, N-MOmentum trial, aquaporin-4, CD19 B-cell depletion, azathioprine, mycophenolate mofetil, immunosuppressants, clinical trial, neuroimmunology, EDSS, autoimmune disease