BOSTON–Aisa Pharma has reported new Phase 2 clinical trial results showing that its experimental drug AISA-021 significantly reduced the frequency and duration of Raynaud’s attacks in patients with systemic sclerosis, a rare autoimmune disease that can cause serious complications affecting blood vessels, skin and internal organs.
The findings from the RECONNOITER-1 clinical trial demonstrated that patients receiving AISA-021 experienced a 43% reduction in the average weekly frequency of Raynaud’s attacks compared with a 26% reduction among patients receiving a placebo.
The Boston-based clinical-stage biopharmaceutical company said the results also showed significant improvements in the number of attack-free days and the duration of episodes, supporting plans to advance the treatment into a global Phase 3 clinical trial.
The new data are being presented at the American College of Rheumatology (ACR) Convergence 2026 meeting, held November 6-11 in Orlando, Florida.
Francesco Del Galdo, Professor and Head of the Scleroderma Program at Leeds University in the United Kingdom, is presenting the findings. Initial results from the study were previously presented at the World Systemic Sclerosis Congress in Athens, Greece, in March 2026.
AISA-021, also known as cilnidipine, is an investigational once-daily oral medication designed to treat systemic sclerosis-associated Raynaud’s phenomenon, a condition characterized by reduced blood flow to the fingers and toes.
Raynaud’s attacks can cause pain, numbness, tingling and changes in skin color, often triggered by cold temperatures or emotional stress. In patients with systemic sclerosis, the condition can be particularly severe because of underlying blood vessel damage and autoimmune-related complications.
“Systemic sclerosis-associated Raynaud’s phenomenon is one of the most debilitating complications of scleroderma, yet patients still lack an FDA-approved treatment option,” said Andrew Sternlicht, MD, Founder and Chief Executive Officer of Aisa Pharma. “The Phase 2 RECONNOITER-1 data demonstrate the potential of AISA-021 to meaningfully reduce both the frequency and burden of Raynaud’s attacks. In addition to achieving a statistically significant reduction in weekly attack frequency, AISA-021 delivered improvements in attack-free days and attack duration, underscoring the potential for a broad clinical benefit. We believe these results, together with the favorable safety and tolerability profile observed to date, support continued development of AISA-021 and provide a strong foundation as we prepare for a global Phase 3 pivotal trial and engage with the FDA on a regulatory pathway toward registration.”
The RECONNOITER trial was a randomized, double-blind, placebo-controlled study involving 64 patients with active systemic sclerosis-associated Raynaud’s phenomenon.
The trial was conducted in two parts, with the newly reported findings coming from Part B, a randomized crossover study evaluating safety and effectiveness in 37 patients.
Participants continued receiving their existing standard-of-care medications, with AISA-021 administered as an additional treatment.
The study population included patients with longstanding disease and substantial previous treatment exposure. The median disease duration was nearly 15 years, and more than 70% of participants were already receiving medication for Raynaud’s symptoms.
Researchers evaluated changes in weekly attack frequency, attack severity and duration, pain, and the number of days without Raynaud’s episodes.
In addition to the overall 43% reduction in attack frequency, patients receiving AISA-021 experienced a statistically significant improvement in attack-free days, with a more than 155% placebo-adjusted improvement and nearly a fourfold increase from baseline.
An analysis of the first treatment sequence showed that patients receiving AISA-021 experienced a 41.7% reduction in attack frequency, compared with a 14.2% reduction among those receiving placebo.
The treatment also significantly reduced the duration of Raynaud’s episodes and improved skin temperature measurements in affected fingers, providing additional evidence of its potential effects on blood circulation.
Patients receiving AISA-021 reported a 42% reduction in scleroderma-related pain, compared with a 15% reduction in the placebo group. However, the difference did not reach conventional statistical significance.
Researchers also identified potentially stronger treatment effects among patients diagnosed with systemic sclerosis within the previous seven years and those with limited rather than diffuse disease.
An analysis of drug concentrations in patients’ blood found that higher exposure to AISA-021 was associated with greater reductions in weekly Raynaud’s attacks and improvements in patient-reported disease burden.
These findings suggest that drug exposure may influence treatment effectiveness, although additional studies will be required to determine the optimal dosing strategy and confirm the clinical benefits.
“The RECONNOITER-1 trial is unique and particularly noteworthy in that it evaluated AISA-021 as an add-on therapy in patients with advanced systemic sclerosis-associated Raynaud’s phenomenon, in a population with a median disease duration of nearly 15 years and substantial prior treatment exposure. More than 70% of patients were receiving active therapy for their Raynaud’s phenomenon, with medications optimized before entering the study. In this difficult-to-treat population, AISA-021 demonstrated clinically meaningful improvements across multiple measures of disease burden while maintaining a safety profile comparable to placebo. These results support a favorable benefit-risk profile and underscore the potential of AISA-021 to address a significant unmet need for patients living with SSc-RP. Importantly, many patients who responded to AISA-021 had previously experienced inadequate efficacy or poor tolerability with conventional calcium channel blockers, highlighting the difference of AISA-021 compared to these agents, and the drug’s potential to provide meaningful clinical benefit in patients with limited treatment options,” Del Galdo said.
AISA-021 was generally well tolerated throughout the study, with no treatment-related serious adverse events reported. The overall incidence of adverse events was comparable between the treatment and placebo groups.
The company said the results support further investigation of AISA-021 as a potential additional treatment for patients whose Raynaud’s symptoms remain inadequately controlled despite existing medications.
Aisa Pharma has submitted a Type C meeting request to the U.S. Food and Drug Administration to discuss its clinical development strategy and potential regulatory pathway.
The company is preparing to initiate a global Phase 3 pivotal trial designed as a randomized, double-blind, placebo-controlled study using parallel treatment groups.
The planned trial will seek to confirm the safety and effectiveness findings observed in Phase 2 and generate the clinical evidence needed to support a potential regulatory application.
AISA-021 remains an investigational therapy, and additional clinical testing will be necessary before its safety and effectiveness can be established for patients with systemic sclerosis-associated Raynaud’s phenomenon.
