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Mirati (MRTX) Down 23% on Mixed Data From Lung Cancer Study

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Mirati Therapeutics (MRTX - Free Report) announced data from the registration-enabling phase II cohort of the KRYSTAL-1 study, which evaluated its KRAS-G12C inhibitor, adagrasib, for non-small cell lung cancer (NSCLC).

Data from the cohort demonstrated that participants who were administered the drug achieved an overall response rate (ORR) of 43% based on the Blinded Independent Central Review (BICR) and an 80% disease control rate (DCR). The median progression free survival (PFS) was 6.5 months. As of Jan 15, 2022 data cut-off, the median overall survival (OS) was 12.6 months.

Mirati’s share price fell 23% in after-hours trading on Thursday (May 26) after it announced the data. Even as Mirati’s adagrasib showed a consistent safety profile, treatment-related adverse effects (TRAEs) were observed in 43% of patients. These reported TRAEs caused discontinuation of therapy by 7% of patients which could have propelled the stock’s decline.

Shares of Mirati have plunged 60.2% in the year-to-date period compared with the industry’s 23.8% decline.

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The above-mentioned registrational enabling cohort evaluated a 600mg dose of adagrasib as a potential treatment for patients with KRAS-G12C-mutated NSCLC. The patients had received at least one prior systemic therapy.

Based on this registrational-enabling cohort, Mirati submitted a new drug application (NDA) with the FDA during fourth-quarter 2021, seeking approval under the accelerated pathway for adagrasib for the aforementioned indication. In February, Mirati announced that the FDA accepted the NDA and set a PDUFA action date of Dec 14, 2022, for the same. A regulatory application seeking approval for adagrasib for the same indication was filed in Europe last week.

Mirati also reported data from an exploratory subgroup analysis from the phase II NSCLC cohort of the KRYSTAL-1 study, which evaluated adagrasib as a potential treatment for KRAS-G12C-mutated NSCLC patients, previously treated with central nervous system (CNS) metastases. Data from the analysis showed that the drug achieved anintracranial (IC) ORR of 33% and an 85% IC DCR.

MRTX also announced its updated findings from a pooled analysis of 132 participants in the KRYSTAL-1 study. As of Oct 15, 2021, data from this analysis showed that the drug achieved an ORR of 44% and an 81% DCR, based on central independent review. The median PFS observed in the study was 6.9 months. As of Jan 15, 2022, the median OS was 14.1 months. Mirati plans to present these findings at the 2022 ASCO Annual Meeting next month.

Currently, there are very limited options available to patients suffering KRAS-G12C mutated NSCLC. A potential approval of adagrasib will provide Mirati with its first marketed drug and the patients with a new therapeutic option.

Mirati’s adagrasib, if approved, will face stiff competition from Lumakras, a KRAS-G12C inhibitor, marketed by Amgen (AMGN - Free Report) . AMGN received accelerated approval for Lumakras as a second-line treatment of locally advanced or metastatic NSCLC from the FDA last May. Earlier in January this year, Amgen also gained approval for the drug in Europe for a similar indication. The drug has shown a robust launch uptake since its approval, with Amgen recording revenues worth $62 million from its sales in first-quarter 2022.

The KRYSTAL-1 study is also evaluating adagrasib in multiple cohorts in combination with other therapies. These include a combo therapy of adagrasib with Merck’s (MRK - Free Report) Keytruda for first-line NSCLC, a combination of adagrasib plus Boehringer Ingelheim’s Gilotrif (afatinib) for advanced NSCLC and adagrasib combined with Bristol-Myers’ (BMY - Free Report) Erbitux for second-line colorectal cancer (CRC).

Mirati is also pursuing a broad combination development program for adagrasib beyond the combinations with Merck’s Keytruda and Bristol-Myers’ Erbitux. These include combinations with SHP2, SOS1 or CDK 4/6 inhibitors.

Both Opdivo and Keutruda are key drivers for Bristol Myers and Merck’s top lines, respectively. During the first quarter of 2022, Bristol Myers recorded $1.9 billion from Opdivo sales while Merck recorded $4.8 billion from Keytruda sales.

Zacks Rank

Mirati currently carries a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.