This week brought a remarkable series of clinical trial readouts spanning oncology, metabolic disease, neurology, and dermatology. Several pivotal datasets were released from late-stage and early-stage programmes, offering fresh hope for patients with conditions ranging from metastatic breast cancer to Parkinson’s disease, with further pivotal data expected at the AAD Annual Meeting in Denver later this month.
Pfizer’s Atirmociclib Delivers Promising Phase 2 Results in Metastatic Breast Cancer
On 17 March, Pfizer announced positive topline results from its randomised Phase 2 FOURLIGHT 1 study evaluating atirmociclib, an investigational oral CDK4 inhibitor, in adults with hormone receptor positive, HER2 negative advanced or metastatic breast cancer. The study enrolled 264 patients across 14 countries whose disease had progressed following prior CDK4/6 inhibitor based treatment.
The trial met its primary endpoint, demonstrating a statistically significant 40 per cent reduction in the risk of disease progression or death (hazard ratio: 0.60; 95% confidence interval: 0.440 to 0.825; p=0.0007) for atirmociclib combined with fulvestrant compared with fulvestrant alone or everolimus plus exemestane. These progression free survival benefits were consistent across all prespecified subgroups, including performance status, menopausal status, and the presence of visceral disease.
Notably, more than 90 per cent of participants had initiated atirmociclib treatment within three months of their last CDK4/6 inhibitor therapy, representing one of oncology’s most difficult to treat populations. The drug was well tolerated, with only 6.4 per cent of patients discontinuing due to treatment emergent adverse events and no new safety signals identified. Overall survival data were not yet mature at the time of analysis.
Unlike currently approved CDK4/6 inhibitors such as palbociclib (Ibrance), ribociclib, and abemaciclib, atirmociclib selectively targets CDK4 alone. This selectivity may reduce CDK6 mediated toxicities, particularly neutropenia, which is a frequent dose limiting side effect of dual inhibitors. A Phase 3 registrational study for atirmociclib in first line metastatic disease is already under way, and Pfizer plans to share results from a separate Phase 2 neoadjuvant study in early breast cancer at a future medical meeting.
Lilly’s Retatrutide Clears First Phase 3 Diabetes Trial with Striking A1C and Weight Reductions
Eli Lilly announced on 19 March that its investigational triple hormone receptor agonist, retatrutide, met the primary and all key secondary endpoints in the TRANSCEND T2D 1 Phase 3 clinical trial. The 40 week, randomised, double blind, placebo controlled study enrolled 537 adults with type 2 diabetes who had inadequate blood sugar control with diet and exercise alone.
Participants receiving retatrutide achieved average A1C reductions of up to 2.0 percentage points, meeting the primary endpoint. For a key secondary endpoint, those on the highest dose lost an average of 36.6 pounds, equivalent to approximately 16.8 per cent of their body weight. Crucially, no weight loss plateau was observed, with participants continuing their weight loss trajectory through the full 40 week treatment period.
Retatrutide is a first in class once weekly subcutaneous injection that simultaneously activates receptors for three gut hormones: glucose dependent insulinotropic polypeptide (GIP), glucagon like peptide 1 (GLP 1), and glucagon. This triple mechanism distinguishes it from Lilly’s own tirzepatide (the active ingredient in Zepbound and Mounjaro), which targets GIP and GLP 1 only, and from Novo Nordisk’s semaglutide (Wegovy/Ozempic), which acts on GLP 1 alone.
The drug also showed clinically meaningful improvements in cardiovascular risk factors, including reductions in non HDL cholesterol, triglycerides, and systolic blood pressure. Side effects were consistent with the GLP 1 class, primarily gastrointestinal in nature, with nausea, diarrhoea, and vomiting among the most commonly reported. Lilly is conducting seven additional Phase 3 trials evaluating retatrutide across indications including obesity, obstructive sleep apnoea, chronic low back pain, and metabolic dysfunction associated steatotic liver disease, with results expected throughout 2026.
Arvinas’ PROTAC Degrader ARV 102 Achieves Landmark LRRK2 Reduction in Parkinson’s Disease
Arvinas presented Phase 1 clinical data for ARV 102 on 18 March at the 2026 International Conference on Alzheimer’s and Parkinson’s Diseases (AD/PD 2026) in Copenhagen. ARV 102 is an investigational oral PROTAC (PROteolysis TArgeting Chimera) degrader designed to cross the blood brain barrier and selectively target and degrade leucine rich repeat kinase 2 (LRRK2), a protein implicated in the development of Parkinson’s disease.
In the randomised, double blind, placebo controlled multiple dose cohort of the Phase 1 trial, ARV 102 achieved approximately 50 per cent or greater reduction of LRRK2 in the cerebrospinal fluid (CSF) at all dose levels by day 14, with the reduction maintained through day 28. This threshold was selected based on evidence that patients with Parkinson’s disease exhibit a two fold elevation of LRRK2 compared to healthy individuals. The drug was well tolerated across all dose levels following 28 days of once daily oral dosing.
Beyond LRRK2 reduction, ARV 102 also reduced endolysosomal and neuroinflammatory biomarkers that are implicated in the pathogenesis of both Parkinson’s disease and progressive supranuclear palsy (PSP). Arvinas noted that this level of biomarker modulation had not previously been demonstrated by LRRK2 inhibitors. The company plans to initiate a Phase 1b trial in PSP in the second quarter of 2026, with the potential to move into a registrational trial later in the year.
AAD 2026 Previews Pivotal Data in Dermatology: Dermatomyositis, Vitiligo, Psoriasis, and Hidradenitis Suppurativa
The 2026 American Academy of Dermatology (AAD) Annual Meeting, taking place in Denver, Colorado, has spotlighted several landmark late breaking datasets poised to reshape treatment across multiple skin conditions.
Brepocitinib in Dermatomyositis: Priovant Therapeutics’ brepocitinib, an oral dual TYK2/JAK1 inhibitor, became the first therapy to demonstrate efficacy in a randomised, placebo controlled Phase 3 trial in dermatomyositis. The VALOR trial, which enrolled 241 patients, met its primary endpoint with a mean Total Improvement Score of 46.5 compared with 31.2 for placebo at week 52 (p=0.0006). All nine key secondary endpoints were also met, and steroid sparing effects were observed. The FDA has accepted the new drug application and granted Priority Review, with a target action date set for the third quarter of 2026. If approved, brepocitinib would become the first targeted therapy for this debilitating condition.
Upadacitinib in Vitiligo: AbbVie’s upadacitinib (Rinvoq) met both co primary endpoints across two replicate Phase 3 Viti Up studies involving approximately 614 adults and adolescents aged 12 years and older with non segmental vitiligo. At week 48, 19.4 and 21.5 per cent of treated patients achieved at least a 50 per cent improvement in total body repigmentation (T VASI 50), compared with 5.9 per cent on placebo. Facial repigmentation of at least 75 per cent (F VASI 75) was achieved by 25.2 and 23.4 per cent of treated patients versus 5.9 and 6.9 per cent on placebo. Regulatory submissions have been filed with both the FDA and EMA. If approved, upadacitinib would become the first systemic therapy indicated for vitiligo.
Envudeucitinib in Plaque Psoriasis: Alumis announced that late breaking Phase 3 data for envudeucitinib in moderate to severe plaque psoriasis will be presented at AAD 2026. Across both trials, 74 per cent of patients achieved PASI 75 at week 16, and by week 24, approximately 65 per cent achieved PASI 90, with more than 40 per cent reaching complete skin clearance (PASI 100). No new safety signals were identified. Full 24 week data are being presented publicly for the first time at the meeting, with a new drug application filing planned for the second half of 2026.
Povorcitinib in Hidradenitis Suppurativa: Incyte’s povorcitinib, a selective oral JAK1 inhibitor, met the primary endpoint of HiSCR50 at week 12 in both Phase 3 STOP HS studies, each enrolling approximately 600 patients. Response rates of 40.2 to 42.3 per cent were observed in the treatment group compared with 28.6 to 29.7 per cent on placebo. The 54 week dataset being presented at AAD 2026 represents the most comprehensive durability evidence for any oral therapy in hidradenitis suppurativa. No major adverse cardiovascular events or deaths were observed through week 24.
Looking Ahead
This week’s results underscore the remarkable breadth of innovation currently advancing through clinical development pipelines worldwide. The coming months promise further milestones, with Lilly expecting seven additional Phase 3 readouts for retatrutide in 2026, Pfizer pressing forward with its atirmociclib registrational programme, and multiple new drug applications under FDA review for conditions that have long lacked effective targeted treatments. Life Science Daily News will continue to bring you comprehensive, timely coverage of the data that matters most to patients, clinicians, and the broader life science community.
This clinical trials roundup is produced by the Life Science Daily News editorial team. All stories are selected and written independently.
