Pharming presents positive Phase II topline data for leniolisib in genetic PIDs with immune dysregulation at ESID 2026

• First clinical data for leniolisib in a larger group of PID participants beyond APDS, supporting the potential of targeted PI3Kδ inhibition to address immune dysregulation
• Leniolisib was well-tolerated, with benefits observed across multiple measures of immune dysregulation, including improvement in lymphoproliferation and positive trends in lung and liver disease markers
• All participants who completed the study elected to continue receiving treatment in a long-term extension study

Leiden, the Netherlands, October 14, 2026: Pharming (Euronext Amsterdam: PHARM/Nasdaq: PHAR), a global biotechnology company focused on rare immune and genetic diseases, today presented positive topline data from its Phase II trial of leniolisib in genetically identifiable primary immunodeficiencies (PIDs) with immune dysregulation linked to altered PI3Kδ signaling. The data, accepted as a late-breaking abstract, were presented as a poster at the 22nd Biennial Meeting of the European Society for Immunodeficiencies (ESID), taking place October 14-17, 2026, in Maastricht, the Netherlands.

“These data provide the first clinical evidence that leniolisib can produce improvements across multiple manifestations of immune dysregulation in conditions beyond APDS, with encouraging signals in lymphoproliferation, pulmonary function, and liver disease,” said Anurag Relan, Chief Medical Officer of Pharming. “The consistent reductions in spleen volume in nearly all evaluable participants are particularly encouraging. Splenomegaly is a measurable sign of lymphoproliferation, and these reductions suggest leniolisib is acting on a core driver of the disease process. The trends in pulmonary findings are also particularly noteworthy, as even small improvements in progressive lung disease were not expected over such a short treatment period.”

This trial is a single-arm, open-label, intra-patient dose-escalation Phase II study that enrolled 13 participants with genetically identifiable PIDs driven by variants in the CTLA4, SOCS1, NFKB1 or FAS genes. Nine of the 13 participants also had a diagnosis of common variable immunodeficiency (CVID). Participants received leniolisib twice daily for 20 weeks, escalating from 10 mg (4 weeks) to 30 mg (4 weeks) to 70 mg (12 weeks). Key results include:

• Safety: Leniolisib was generally well-tolerated across all 4 genotypes associated with dysregulated PI3Kδ signaling. Safety findings were consistent with the known disease profile, with infections as the most common adverse events (AEs) observed, and no new safety signals identified. All treatment-related AEs were Grade 1. Two study participants experienced serious AEs that were deemed unrelated to leniolisib. One participant, with a history of portal hypertension, discontinued treatment early due to acute hepatitis.
• Spleen volume: Mean reduction from baseline of 26.4% (n=11), with reductions observed in 10 of 11 evaluable participants.
• Lymph nodes: Mean reduction from baseline of 33.7% in index lesion size (n=4), with reductions observed in all four evaluable participants.
• Pulmonary function: Among participants with impaired gas exchange at baseline (n=7), the percent predicted diffusing capacity of the lungs for carbon monoxide (DLCO) increased by a mean of 8.0%. Consistent with this, CT-assessed interstitial lung disease scores also decreased in 4 of 5 evaluable participants.
• Liver: Improvement in liver stiffness in 2 of 3 participants with heightened stiffness at baseline.
• All 12 participants who completed the study enrolled in the three-year extension study (NCT06990529).

Added Dr. Relan: “Together, these results reinforce our broader strategy of evaluating PI3Kδ inhibition across PIDs characterized by immune dysregulation, regardless of genetic cause. We look forward to reporting topline results from our separate Phase II trial in CVID, expected in November, which will inform our plans for a potential registrational study in the broader CVID population.”

Based on estimated prevalence rates, these genetically identifiable PIDs and CVID with immune dysregulation represent a broader potential patient population than APDS, with estimated prevalence of approximately 7.5 patients per million for genetic PIDs and approximately 39 patients per million for CVID, including overlap between the genetic PID and CVID populations, compared with approximately 1.5 patients per million for APDS.

About leniolisib
Leniolisib is an oral, selective phosphoinositide 3-kinase delta (PI3Kδ) inhibitor designed to address PI3Kδ-driven immune dysregulation across primary immunodeficiencies (PIDs).

Leniolisib, marketed under the brand name Joenja®, is approved and commercially available in multiple countries for the treatment of activated phosphoinositide 3-kinase delta syndrome (APDS) an ultra-rare and progressive PID characterized by immune dysregulation and deficiency.

Beyond APDS, leniolisib is being evaluated in clinical trials for additional PIDs characterized by PI3Kδ-driven immune dysregulation, including common variable immunodeficiency (CVID). These PIDs share many of the same clinical manifestations, including lymphoproliferation, autoimmunity, gastrointestinal disease, and lung disease. The safety and efficacy of leniolisib have not been established for these investigational uses.

About Pharming
Pharming Group N.V. (Euronext Amsterdam: PHARM/Nasdaq: PHAR) is a global biotechnology company that develops and commercializes innovative medicines for people living with rare immune and genetic diseases.

We combine specialized scientific, medical, regulatory and commercial expertise to advance a focused portfolio of approved medicines and development programs that address significant unmet medical needs. Guided by insights from patients and the wider rare disease community, we are dedicated to delivering innovative therapies for some of the most challenging rare diseases.

Pharming is headquartered in Leiden, the Netherlands, with operations in the United States and Europe. 

For more information, visit www.pharming.com and find us on LinkedIn.

For further public information, contact:
Pharming
Michael Levitan, VP Investor Relations & Capital Markets 
T: +1 (908) 705 1696 
E: investor@pharming.com 

Saskia Mehring, Head of Corporate Communications 
T: +31 6 28 32 60 41 
E: mailto:media.relations@pharming.com

Media Relations 
Julia Deutsch (Lyra Strategic Advisory on behalf of Pharming)
E: JDeutsch@lyraadvisory.com

Netherlands: Leon Melens (LifeSpring Life Sciences Communication on behalf of Pharming) 
T: +31 6 53 81 64 27 

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Attachment

• Pharming presents Phase II topline data leniolisib PIDs_EN_14OCT2026