China NMPA Accepts NDA Submission of Ripretinib for Advanced Gastrointestinal Stromal Tumor

SHANGHAI andSAN FRANCISCOandWALTHAM,Mass.,July 20,2020 -- Zai Lab Limited (NASDAQ: ZLAB) andDeciphera Pharmaceuticals,Inc.(NASDAQ: DCPH) today announced that theChina National Medical Products Administration(NMPA) has accepted its New Drug Application (NDA) for ripretinib for the treatment of adult patients with advanced gastrointestinal stromal tumor (GIST) who have received prior treatment with 3 or more kinase inhibitors,including imatinib. Ripretinib was recently granted full approval by theU.S. Food and Drug Administration(FDA) for the treatment of fourth-line GIST. Ripretinib is also approved byHealth Canadafor the treatment of adult patients with advanced GIST who have received prior treatment with imatinib,sunitinib,and regorafenib and by theAustralian Therapeutic Goods Administrationfor the treatment of adult patients with advanced GIST who have received prior treatment with 3 or more kinase inhibitors,including imatinib.

"There is a significant unmet medical need for patients with GIST inChina,especially for those who are refractory to prior therapies. Based on the recent fullU.S.FDA approval and compelling clinical data from the INVICTUS trial(1),we believe ripretinib has the potential to alter the treatment landscape for GIST patients in China," said Dr.Samantha Du,Founder,Chairperson and Chief Executive Officer ofZai Lab. "We look forward to working closely with the NMPA to make a profound impact on the way GIST is treated in China."

"The earlier than expected acceptance of the ripretinib NDA inChinaunderscores its potential and follows the recent FDA approval in the U.S.," saidSteve Hoerter,President and Chief Executive Officer of Deciphera. "The magnitude of the unmet need for GIST patients inChinais striking,with over 30,000 Chinese patients reportedly diagnosed each year. We look forward to our continued collaboration with Zai as we work to bring ripretinib to patients who are waiting for an additional treatment option."

INVICTUS is a Phase 3 randomized,double-blind,placebo-controlled,international,multicenter clinical study designed to evaluate the safety,tolerability,and efficacy of ripretinib compared to placebo in 129 patients with advanced GIST whose previous therapies have included imatinib,and regorafenib. Patients were randomized 2:1 to either 150 mg of ripretinib or placebo once daily. The primary efficacy endpoint was progression-free survival (PFS) as determined by independent radiologic review using modified Response Evaluation Criteria in Solid Tumors (RECIST). As previously reported,the median PFS in the study was 6.3 months compared to 1.0 month in the placebo arm,with significantly reduced the risk of disease progression or death of 85% (hazard ratio of 0.15,p<0.0001). Secondary endpoints as determined by independent radiologic review using modified RECIST included Objective Response Rate (ORR) and Overall Survival (OS). Ripretinib demonstrated an ORR of 9.4% compared with 0% for placebo (p=0.0504). Ripretinib also demonstrated a median OS of 15.1 months compared to 6.6 months in the placebo arm and reduced the risk of death by 64% (hazard ratio of 0.36).

The most common adverse reactions (>=20%) were alopecia,fatigue,nausea,abdominal pain,constipation,myalgia,diarrhea,decreased appetite,palmar-plantar erythrodysesthesia syndrome,and vomiting. Adverse reactions resulting in permanent discontinuation occurred in 8% of patients,dosage interruptions due to an adverse reaction occurred in 24% of patients and dose reductions due to an adverse reaction occurred in 7% of patients who received ripretinib.

Note: (1) NDA submission is supported by strong results from the INVICTUS pivotal Phase 3 study showing clinically meaningful improvement in both progression-free survival and overall survival.

About Ripretinib

Ripretinib is a switch-control tyrosine kinase inhibitor that was engineered to broadly inhibit KIT and PDGFRα mutated kinases by using a unique dual mechanism of action that regulates the kinase switch pocket and activation loop. Ripretinib inhibits primary and secondary KIT mutations in exons 9,11,13,14,17,and 18,involved in GIST,as well as the primary exon 17 D816V mutation involved in systemic mastocytosis,or SM. Ripretinib also inhibits primary PDGFRα mutations in exons 12,including the exon 18 D842V mutation,involved in a subset of GIST.

Ripretinib is approved by theU.S.FDA under the brand name QINLOCK™ for the treatment of adult patients with advanced GIST who have received prior treatment with 3 or more kinase inhibitors,including imatinib. Ripretinib is also approved byHealth Canadaunder the brand name QINLOCK for the treatment of adult patients with advanced GIST who have received prior treatment with imatinib,and regorafenib and by theAustralian Therapeutic Goods Administrationunder the brand name QINLOCK for the treatment of adult patients with advanced GIST who have received prior treatment with 3 or more kinase inhibitors,including imatinib.

Deciphera Pharmaceuticalsis developing ripretinib for the treatment of KIT and/or PDGFRα-driven cancers,including GIST,SM,and other cancers.

Zai Labhas an exclusive license agreement with Deciphera for the development and commercialization of ripretinib inGreater China,including mainlandChina,Hong Kong,MacauandTaiwan.

AboutZai Lab

Zai Lab(NASDAQ:ZLAB) is an innovative commercial stage biopharmaceutical company focused on bringing transformative medicines for cancer,infectious and autoimmune diseases to patients inChinaand around the world. To quickly target the large,fast-growing segments of China's pharmaceutical market and address unmet medical needs,Zai Lab's experienced team has secured partnerships with leading global biopharma companies,generating a broad pipeline of innovative drug candidates.Zai Labhas also built an in-house team with strong drug discovery and translational research capabilities,aiming to establish a global pipeline of proprietary drug candidates against targets in our focus areas. Zai Lab's vision is to become a fully integrated biopharmaceutical company,discovering,developing,manufacturing and commercializing its portfolio in order to impact human health worldwide.

For additional information about the company,please visitwww.zailaboratory.comor follow us atwww.twitter.com/ZaiLab_Global.

AboutDeciphera Pharmaceuticals

Deciphera is a biopharmaceutical company focused on discovering,developing and commercializing important new medicines to improve the lives of people with cancer. We are leveraging our proprietary switch-control kinase inhibitor platform and deep expertise in kinase biology to develop a broad portfolio of innovative medicines.In addition to advancing multiple product candidates from our platform in clinical studies,QINLOCK™is Deciphera's FDA-approved switch-control kinase inhibitor for the treatment of fourth-line gastrointestinal stromal tumors.For more information,please visit the company's website atwww.deciphera.com.