Sihuan Pharmaceutical Announces Significant Positive Phase III Data for Dirozalkib in First-Line ALK-Positive Advanced NSCLC

Key Highlights from the Announcement

• Sihuan Pharmaceutical Holdings Group Ltd. (HKEX: 0460) reported highly positive Phase III trial results for its ALK inhibitor, dirozalkib, at the 2026 American Association for Cancer Research Annual Meeting (AACR).
• The pivotal DIAMOND-2 study demonstrates statistically and clinically significant efficacy of dirozalkib compared to crizotinib in the first-line treatment of ALK-positive advanced non-small cell lung cancer (NSCLC).
• The trial results indicate substantial improvements in survival and response rates—likely to be considered price-sensitive information by investors.

Detailed Results from the DIAMOND-2 Study

• Study Design:
  • Multicenter, randomized, open-label Phase III trial in China.
  • Enrolled 275 ALK-positive advanced NSCLC patients, randomized 1:1 to receive dirozalkib (500 mg once daily) or crizotinib (250 mg twice daily).
  • Primary endpoint: Investigator-assessed progression-free survival (PFS).
  • Secondary endpoints: Objective response rate (ORR), duration of response (DoR), intracranial ORR (IC-ORR), and safety.
• Efficacy Results:
  • Median PFS: Dirozalkib group achieved 31.3 months vs. 12.9 months in the control (crizotinib) group—a 53% reduction in the risk of disease progression (HR=0.47, P<0.0001).
  • ORR: 88.5% in the dirozalkib group.
  • Median DoR: 32.10 months.
  • Disease Control Rate (DCR): 95.4% for dirozalkib, indicating deeper and more durable tumor responses.
• Intracranial Activity:
  • For patients with measurable intracranial lesions at baseline, dirozalkib demonstrated an intracranial ORR of 91.7% versus only 11.1% for the control group.
  • Intracranial PFS was significantly prolonged, with a 55% reduction in risk of intracranial disease progression (HR=0.45, P=0.0003).
• Safety:
  • Dirozalkib was generally well-tolerated; most adverse events were mild (Grade 1–2 gastrointestinal issues).
  • Discontinuation rate due to dirozalkib-related adverse events was only 1.5%, supporting a favorable safety profile.

About Dirozalkib (Xuan Fei Ning)

• Dirozalkib is a next-generation oral ALK inhibitor, independently developed by Xuanzhu Biopharm (a non-wholly owned subsidiary of Sihuan Pharmaceutical).
• It features a novel molecular structure with high affinity for the ALK kinase domain, and demonstrates potent activity against common resistance mutations (including G1202R and I1171N) that limit earlier ALK inhibitors.
• Exhibits significant efficacy in penetrating the blood-brain barrier, enabling robust intracranial tumor control.
• Received NMPA approval in August 2025 for first-line treatment of ALK-positive, locally advanced or metastatic NSCLC.

Corporate Background

Xuanzhu Biopharm

• Listed on HKEX in October 2025 (Stock Code: 02575.HK).
• Focuses on R&D, production, and commercialization of innovative drugs, with strong expertise in small and large molecule pharmaceuticals.
• Product pipeline includes small molecule chemistry, large molecule biopharmaceuticals, and ADCs (antibody-drug conjugates).

Sihuan Pharmaceutical Holdings Group

• Founded in 2001; listed on HKEX in 2010.
• Has a comprehensive R&D platform, efficient production, and a mature sales system.
• Pursues a dual-engine strategy, combining medical aesthetics with biopharmaceutical innovation.

Potential Share Price Impact and Investor Takeaways

• The data presented is likely to be considered highly price-sensitive—the statistically significant and clinically meaningful superiority of dirozalkib over crizotinib in first-line ALK-positive NSCLC positions the drug as a potential new standard of care in China and possibly globally.
• Strong efficacy, especially in controlling brain metastases, and a favorable safety profile could support broad physician acceptance and market uptake.
• Dirozalkib’s approval and positive pivotal data may drive further regulatory milestones, commercial partnerships, and revenue growth for Sihuan Pharmaceutical and Xuanzhu Biopharm.
• Investors should monitor for NMPA reimbursement decisions, international regulatory filings, and any updates on commercial rollout, as these could further influence share price volatility.

Disclaimer: This article is for informational and reference purposes only and does not constitute investment advice or a solicitation to buy or sell any securities. Investors should conduct their own due diligence and consult professional advisors before making investment decisions. The information above is based on the latest company filings and public disclosures as of April 2026.

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