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CStone Announces the First-in-Class Registrational Clinical Trial of Sugemalimab Met its Primary Endpoint in Stage III NSCLC and Plans to Submit a New Drug Application

SUZHOU, China, May 28, 2021 /PRNewswire=KYODO JBN/ --

-Sugemalimab becomes the world's first anti-PD-1/PD-L1 monoclonal antibody to

successfully improve progression-free survival (PFS) in patients with stage III

non-small-cell lung cancer (NSCLC) without disease progression after concurrent

or sequential chemoradiotherapy

-Sugemalimab is also the world's first anti-PD-1/PD-L1 monoclonal antibody

covering both locally advanced/unresectable (stage III) and metastatic (stage

IV) NSCLC patients

-CStone plans to submit a New Drug Application (NDA) to the National Medical

Products Administration (NMPA) of China for sugemalimab in stage III NSCLC and

will work closely with EQRx on regulatory discussions for new drug applications

for the two indications of stage III and stage IV NSCLC in multiple countries

including the U.S.

CStone Pharmaceuticals ("CStone", HKEX: 2616), a leading biopharmaceutical

company focused on researching, developing, and commercializing innovative

immuno-oncology therapies and precision medicines, today announced that a

registrational clinical trial (GEMSTONE-301 study) of the anti-PD-L1 monoclonal

antibody sugemalimab in patients with stage III NSCLC met its primary endpoint

at a planned interim analysis reviewed by the independent Data Monitoring

Committee (iDMC). The findings showed that sugemalimab as a consolidation

therapy brought statistically significant and clinically meaningful improvement

in the Blinded Independent Central Review (BICR) assessed PFS in patients with

locally advanced/unresectable NSCLC without disease progression after

concurrent or sequential chemoradiotherapy. Investigator assessed PFS showed

consistent results as those of the primary endpoint. Sugemalimab was

well-tolerated with no new safety signals. Subgroup analyses demonstrated that

sugemalimab was associated with clinical benefit regardless of whether patients

received concurrent or sequential chemoradiotherapy prior to sugemalimab.

"Lung cancer is the leading cause of cancer-related mortality globally. There

are currently few effective therapies for patients with stage III NSCLC whose

disease did not progress after sequential chemoradiotherapy," said Professor

Yi-long Wu of Guangdong Provincial People's Hospital, the Leading Principal

Investigator on the GEMSTONE-301 study," The successful results from the study

indicate that sugemalimab will meet the urgent treatment needs of these

patients."

"We are excited that sugemalimab becomes the first anti-PD-1/PD-L1 monoclonal

antibody in the world to cover both stage III and stage IV NSCLC patients,"

said Dr. Frank Jiang, Chairman and CEO of CStone, "The continued success of

sugemalimab in lung cancer demonstrates CStone's leading research and

development capabilities in the field of immuno-oncology. We are working

closely with Pfizer and EQRx, our commercial partners for sugemalimab, on the

next steps in our joint efforts to deliver this best-in-class drug to patients

worldwide."

"Currently, there has not been an approved PD-1 or PD-L1 monoclonal antibody

for treating patients in stage III NSCLC who have not developed disease

progression after sequential chemoradiotherapy," said Dr. Jason Yang, Chief

Medical Officer of CStone, "The GEMSTONE-301 is the first-in-class clinical

study design that enrolled patients with either concurrent or sequential

chemoradiotherapy to better reflect real-world clinical practice and cover a

broader population. CStone is committed to providing treatment options to

address the unmet medical needs. The GEMSTONE-301 study will advance the use of

multidisciplinary treatment approaches in China to improve the quality of the

diagnosis and treatment of stage III NSCLC. We will continue to explore the

potential of sugemalimab in registrational clinical trials for patients with

hematologic malignancies and advanced gastric and esophageal cancers."

CStone plans to submit an NDA to the NMPA for sugemalimab in stage III NSCLC,

and will work with EQRx to hold regulatory discussions on the indications of

stage III and stage IV NSCLC with regulators in multiple countries, including

the U.S. Food and Drug Administration (FDA). Specific study data will be

presented at an upcoming academic conference.

CStone formed a strategic collaboration agreement with Pfizer that includes the

development and commercialization of sugemalimab in mainland China, and a

framework to bring additional oncology assets to the Greater China market.

CStone subsequently formed a strategic collaboration agreement with EQRx, under

which EQRx licensed the exclusive rights to two key late-stage immuno-oncology

assets, sugemalimab and CS1003 (anti-PD-1 antibody), for global development and

commercialization outside of Greater China.

About NSCLC

In recent years, China has had rising lung cancer incidence. According to the

latest estimates on the global burden of cancer released by International

Agency for Research on Cancer (IARC), in 2020, an estimated 0.82 million new

lung cancer cases and 0.71 million new lung cancer deaths occurred in China.

Among all Chinese cancer patients, lung cancer is the leading cause of

cancer-related deaths. NSCLC is the most common type of lung cancer.

There are currently limited treatment options for patients with locally

advanced/unresectable (stage III) NSCLC. In China, sequential chemoradiotherapy

is widely used , while concurrent chemoradiotherapy is with limited use. But

both are with unsatisfactory efficacy.

About Sugemalimab (anti-PD-L1 antibody)

Sugemalimab is an investigational anti-PD-L1 monoclonal antibody discovered by

CStone. Authorized by the U.S.-based Ligand Corporation, sugemalimab is

developed by the OmniRat® transgenic animal platform, which can generate fully

human antibodies in one stop. As a fully human, full-length anti-PD-L1

monoclonal antibody, sugemalimab mirrors the natural G-type immunoglobulin 4

(IgG4) human antibody, which reduces the risk of immunogenicity and potential

toxicities in patients, a unique advantage over similar drugs.

Currently, sugemalimab is being investigated in a number of ongoing clinical

trials, including one Phase II registration studies for lymphoma (CS1001-201)

and four Phase III registrational studies on stage III NSCLC, stage IV NSCLC,

gastric cancer, and esophageal cancer, respectively.

CS1001-201 is a single-arm, multicenter, Phase II pivotal study designed to

evaluate the efficacy and safety of sugemalimab as monotherapy for the

treatment of adult patients with relapsed or refractory extranodal natural

killer/T-cell lymphoma (R/R ENKTL). Based on the encouraging preliminary

efficacy results, sugemalimab was granted Orphan Drug Designation for the

treatment of T-cell lymphoma and Breakthrough Therapy Designation for the

treatment of R/R ENKTL by the U.S. Food and Drug Administration. It has also

been granted Breakthrough Therapy Designation by the National Medical Products

Administration of China. The proposed indication is R/R ENKTL.

GEMSTONE-301 Study

GEMSTONE-301 study (clinicaltrials.gov registration number: NCT03728556; drug

clinical trial registration number: CTR20181429) is a multicenter, randomized,

double-blind Phase III clinical trial, designed to evaluate the efficacy and

safety of sugemalimab as consolidation therapy in patients with locally

advanced/unresectable stage III NSCLC without disease progression after

concurrent or sequential chemoradiotherapy. The trial's primary endpoint was

PFS as assessed by BICR according to RECIST v1.1; the secondary endpoints

included overall survival, PFS as assessed by investigators and safety profile.

GEMSTONE-302 Study

GEMSTONE-302 (clinicaltrials.gov registration number: NCT03789604; drug

clinical trial registration number: CTR20181452) is a randomized, double-blind

Phase III study, designed to evaluate the efficacy and safety of anti-PD-L1

monoclonal antibody sugemalimab combined with chemotherapy as the first-line

treatment in naive patients with stage IV non-small cell lung cancer (NSCLC) it

vs. placebo combined with chemotherapy. The primary endpoint of the study was

investigator-assessed PFS. Secondary endpoints included overall survival,

BICR-assessed PFS and safety.

In August 2020, GEMSTONE-302 study met its primary endpoint of significantly

prolonging progression-free survival (PFS) and reducing the risk of disease

progression or death by 50% with sugemalimab combined with chemotherapy

compared to placebo combined with chemotherapy, as assessed by iDMC at the

planned interim analysis.

Subgroup analysis showed clinical benefit in patients with squamous versus

non-squamous NSCLC, and in patients with PD-L1 expression >=1% versus PD-L1

expression <1%.

Sugemalimab in combination with chemotherapy was well tolerated, no new safety

signals were identified. Specific study data were presented in a Proffered

Paper Oral Presentation (Late-Breaking Abstract) at ESMO Asia 2020. In November

2020, the National Medical Product Administration of China accepted the New

Drug Application for sugemalimab combined with chemotherapy for the first-line

treatment of advanced squamous and non-squamous non-small cell lung cancer

patients.

About CStone

CStone Pharmaceuticals (HKEX: 2616) is a biopharmaceutical company focused on

researching, developing, and commercializing innovative immuno-oncology and

precision medicines to address the unmet medical needs of cancer patients in

China and worldwide. Established in 2015, CStone has assembled a world-class

management team with extensive experience in innovative drug development,

clinical research, and commercialization. The company has built an

oncology-focused pipeline of 14 drug candidates with a strategic emphasis on

immuno-oncology combination therapies. Currently, CStone has received three

drug approvals in Greater China, including two in Mainland China and one in

Taiwan. CStone's vision is to become globally recognized as a world-renowned

biopharmaceutical company by bringing innovative oncology therapies to cancer

patients worldwide.

For more information about CStone, please visit: www.cstonepharma.com

About Pfizer

At Pfizer, we apply science and our global resources to bring therapies to

people that extend and significantly improve their lives. We strive to set the

standard for quality, safety and value in the discovery, development and

manufacture of health care products, including innovative medicines and

vaccines. Every day, Pfizer colleagues work across developed and emerging

markets to advance wellness, prevention, treatments and cures that challenge

the most feared diseases of our time. Consistent with our responsibility as one

of the world's premier innovative biopharmaceutical companies, we collaborate

with health care providers, governments and local communities to support and

expand access to reliable, affordable health care around the world. For more

than 170 years, we have worked to make a difference for all who rely on us. We

routinely post information that may be important to investors on our website at

www.Pfizer.com.

ABOUT EQRx

EQRx is committed to catalyzing a market-based solution to one of society's

biggest healthcare challenges by developing important new medicines and

offering them at lower prices. Through strategic partnerships with stakeholders

from across the healthcare system and cutting-edge science and technology, the

Company aims to provide high-quality, patent-protected medicines more

efficiently and cost-effectively than ever before. EQRx is a purpose-built

disruptor at scale, remaking medicine to bend the cost curve in drug pricing.

To learn more, visit www.eqrx.com.

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Source:CStone Pharmaceuticals