Mirati to focus adagrasib/Keytruda study in low PDL1 lung cancer patients

Mirati Therapeutics

05/12/2022 23:05

By Deena Beasley
       Dec 5 (Reuters) - Early trial data shows that a
combination of Mirati Therapeutics  MRTX.O  experimental drug
adagrasib and Merck & Co's  MRK.N  immunotherapy Keytruda helped
about half of previously untreated metastatic lung cancer
patients, with manageable side effects, Mirati said on Monday.
    The company expects the largest advantage in patients with
lower levels of PDL1, the protein targeted by Keytruda, and 
plans to launch a Phase 3 trial enrolling only those patients by
the end of this year, Mirati Chief Executive Officer David Meek
told Reuters.
    The trial will compare the adagrasib combination with the
current standard of care, which is chemotherapy plus Keytruda,
also known as pembrolizumab. The initial treatment for patients
with higher levels of PDL1 is Keytruda alone, and Mirati will
likely begin planning next year for a combination study in those
patients, Meek said.
    Recent study data shows that 19.4% of previously untreated,
metastatic NSCLC patients treated with Keytruda plus
chemotherapy were alive after five years, compared with 11.3% of
patients treated with a placebo and chemotherapy.
    Adagrasib is an oral drug designed to target a mutated form
of a gene known as KRAS that occurs in about 13% of non-small
cell lung cancers (NSCLC), the most common form of the disease,
and less frequently in some other solid tumors.
    Out of seven Phase 2 trial patients given the combination
treatment, at a median follow-up of 19 months, four (57%) had
tumor shrinkage of at least 30%, and none had tumor growth,
Mirati said.
    A preliminary analysis of 53 patients showed that 49% of
them had responded to the combination treatment, and 89% had
controlled disease.
    Serious side effects occurred in 44% of patients, including
increased levels of pancreatic enzymes in 11%, and higher liver
enzymes in 8-9%. Mirati said the rates were consistent with
levels seen when either drug is used on its own.
    Amgen Inc  AMGN.O , which sells a KRAS-inhibitor called
Lumakras, earlier this year said it had shelved immunotherapy
combination studies after finding that high numbers of patients
experienced liver toxicity.
    Mirati expects to hear by Dec. 14 on its application to the
U.S. Food and Drug Administration for approval to sell adagrasib
for treating patients with advanced NSCLC who have stopped
responding to other drugs.
    Meek declined to comment on takeover speculation that has
pushed shares of Mirati up nearly 40% since mid-November.
    "We're laser-focused on crossing the finish line with the
approval and then we have to launch the drug ... We're so busy
right now," he said.    
 (Reporting by Deena Beasley in Los Angeles
Editing by Matthew Lewis
)
 ((deena.beasley@thomsonreuters.com; 213 955 6746; Reuters
Messaging: deena.beasley.thomsonreuters.com@reuters.net))