Minghui Pharmaceutical Presents Phase 1/2 Clinical Data of MHB088C (B7-H3 ADC) as Monotherapy for the Treatment of Patients with Recurrent or Metastatic Solid Tumors at the 2024 ASCO Annual Meeting

SHANGHAI, June 3, 2024 /PRNewswire/ -- Minghui Pharmaceutical, Inc., a late-stage clinical biopharmaceutical company, announced today that the preliminary Phase 1/2 clinical data of MHB088C (B7-H3 ADC) was presented at the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting in an oral presentation.

Abstract #: 3012

Results of a Phase 1/2 Study of MHB088C: a Novel B7-H3 Antibody-Drug Conjugate (ADC) Incorporating a Potent DNA Topoisomerase I Inhibitor in Recurrent or Metastatic Solid Tumors

In this Phase 1/2 study, the safety/tolerability, pharmacokinetics, and efficacy of MHB088C in patients (pts) with recurrent or metastatic solid tumors were evaluated. The study results were as follows:

• At data cutoff, MHB088C was well tolerated. The most common TRAEs were hematological toxicities. 4 mg/kg Q3W was the DLT dose and 3 mg/kg Q3W was defined as the MTD. 1.6 mg/kg Q2W, 2.0 mg/kg Q3W and 2.4 mg/kg Q3W demonstrated favorable safety profiles with low single-digit Grade ≥3 hematological AEs for the two lower doses. No interstitial lung disease (ILD) was reported as of the data cutoff.
• ­ Of 98 efficacy evaluable pts with different tumor types at doses ranging from 0.8 mg/kg to 4.0mg/kg, ORR was 33.7% (33/98) and DCR was 83.7% (82/98), with DoR not reached yet. The majority of pts remain on the treatment.
• ­ Of 31 efficacy evaluable pts with small cell lung cancer (SCLC), ORR was 61.3% (19/31) and DCR was 93.5% (29/31). 24 pts (77.4%) remain on the treatment, and 6 pts (19.4%) achieved 60% or more tumor reduction, with 2 CRs of target lesion at 3.0 mg/kg. Among 10 pts at 1.6 mg/kg Q2W, ORR was 80% and DCR was 90%.
• ­ Of 7 efficacy evaluable pts with esophageal squamous cell carcinoma (ESCC), ORR was 42.9% and DCR was 85.7%. The median follow-up was over 3.0 months.

Professor Lin Shen from the Beijing Cancer Hospital stated: "MHB088C represents an innovative advancement in cancer treatment as a novel B7-H3 ADC equipped with a potent DNA Topo I inhibitor. The preliminary data are highly encouraging, showcasing clinically meaningful and durable antitumor activities at very safe doses across multiple cancer types. We are optimistic about the ongoing study and anticipate further positive clinical outcomes."

Dr. Guoqing Cao, CEO of Minghui Pharmaceutical, stated: "We are excited to share the results of Phase 1/2 study of MHB088C at the 2024 ASCO. MHB088C is a well-differentiated B7-H3 ADC, conjugating an optimal anti-human B7-H3 antibody with our Proprietary SuperTopoi^TM payload. We are seeing robust efficacy at very safe doses without major hematological toxicity or ILD. Particularly, in SCLC, 9 out of 10 patients experienced tumor shrinkage at 1.6 mg/kg Q2W, with an ORR of 80%. The durability of responses was also notable in ESCC, with an ORR of 43% and median follow-up over 3 months.

The safety profile of MHB088C is consistent with that of our other program MHB036C, a TROP-2 ADC, without major hematological toxicity or ILD either. Between the two clinical programs, with data from more than 250 patients, we are confident that we now have one of the best ADC platforms in the industry. Efficacy in other cancer types has also been observed and will be reported in future conferences. We look forward to initiating registrational trials of the monotherapy for selected tumor types by the end of 2024 and exploring the IO combination in earlier line settings for both ADC assets in the near future."

About MHB088C
MHB088C is a novel B7-H3 ADC generated through Minghui's SuperTopoi^TM ADC platform. Minghui's proprietary payload is 5 to 10 times more potent than DXd, retaining key advantages such as bystander effect while eliminating the risk of interstitial lung disease. Conjugated with Minghui's proprietary B7-H3 antibody, which has superior binding and internalization compared to the competitor's antibodies, MHB088C has demonstrated remarkable anti-tumor efficacy across various cancer types. It was 3 to 10 times more potent in killing tumor cells than the competitor's compound in xenograft models.

About Minghui Pharmaceutical
Minghui Pharmaceutical, Inc. is a late-stage clinical biopharmaceutical company dedicated to developing innovative medicines for unmet medical needs in oncology and autoimmune diseases. Leveraging the expertise in medical science and the proprietary technology platforms, the company is developing a rich clinical-stage pipeline including a variety of first-in-class or best-in-class product candidates. For more information, please visit www.minghuipharma.com.

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