On October 22, 2023 Amgen (NASDAQ:AMGN) reported data from the global Phase 3 CodeBreaK 300 trial evaluating two doses of LUMAKRAS (sotorasib) (960 mg or 240 mg) in combination with Vectibix (panitumumab) (Press release, Amgen, OCT 22, 2023, View Source [SID1234636201]). Both doses demonstrated a statistically significant superiority in progression-free survival (PFS) over the investigator’s choice of therapy in patients with chemorefractory KRAS G12C-mutated metastatic colorectal cancer (mCRC). The results are being presented today at the Presidential Symposium 2 session as a late-breaking oral presentation (LBA10) during the European Society for Medical Oncology (ESMO) (Free ESMO Whitepaper) 2023 Congress in Madrid, Spain, with simultaneous publication in the New England Journal of Medicine.

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"The CodeBreaK 300 trial demonstrated the benefit of LUMAKRAS plus Vectibix to deliver statistically significant PFS outcomes for patients compared to the investigator’s choice of therapy, offering new hope to this population with historically poor outcomes," said David M. Reese, M.D., executive vice president, Research and Development at Amgen.

After a median follow-up of 7.8 months, the median PFS was 5.6 months and 3.9 months with LUMAKRAS 960 mg plus Vectibix and LUMAKRAS 240 mg plus Vectibix respectively, versus 2.2 months with investigator’s choice of therapy (trifluridine and tipiracil, or regorafenib). The improvement in PFS for patients treated with LUMAKRAS plus Vectibix was seen across key subgroups, including tumor sidedness, primary tumor location, prior lines of therapy and presence or absence of liver metastases. Among secondary endpoints, higher objective response rate (ORR) and disease control rate (DCR) were observed in patients treated with LUMAKRAS plus Vectibix at both doses versus investigator’s choice of care. Patients at both dose regimens of LUMAKRAS plus Vectibix experienced a longer duration of treatment than those treated with investigator’s choice therapy.

"With these new data, sotorasib plus panitumumab showed consistent efficacy across key subgroups at both doses and supports the biologic rationale of combining these two biomarker-directed therapies," said Filippo Pietrantonio, M.D., Fondazione IRCCS Istituto Nazionale dei Tumori. "Fewer than 20% of people diagnosed with mCRC survive beyond five years, and additional treatment options are clearly needed, particularly for the patients with KRAS mutations for whom evidence-based targeted options were not yet available."

The most common Grade ≥3 treatment-related adverse events (TRAEs) with LUMAKRAS plus Vectibix were dermatitis acneiform (960 mg: 11%; 240 mg: 4%), hypomagnesemia (960 mg: 6%; 240 mg: 8%), rash (960 mg: 6%; 240 mg: 2%), and diarrhea (960 mg: 4%; 240 mg: 6%).

Based on the CodeBreaK 300 primary analysis results, Amgen is planning to submit these data to regulatory authorities.

About CodeBreaK 300
The CodeBreaK 300 trial enrolled 160 participants and compared LUMAKRAS at doses of 960 mg and 240 mg in combination with Vectibix to investigator’s choice of standard of care (trifluridine and tipiracil, or regorafenib) in patients with chemorefractory KRAS G12C-mutated metastatic colorectal cancer (mCRC).

The primary endpoint was PFS, and key secondary endpoints were overall survival (OS) and objective response rate (ORR).

The median PFS for patients treated with the 960 mg dose of LUMAKRAS plus Vectibix (n=53) was 5.6 months (Hazard Ratio (HR) 0.49 (95% Confidence Interval (CI): 0.30, 0.80)).
The median PFS for patients treated with the 240 mg dose of LUMAKRAS plus Vectibix (n=53) was 3.9 months (HR 0.58 (95% CI: 0.36, 0.93)).
The median PFS for patients treated with investigator’s choice (n=54) was 2.2 months.
LUMAKRAS plus Vectibix combination regimens demonstrated higher ORR compared with investigator’s choice (95% CI; 960 mg: 26% [15.3–40.3]; 240 mg: 6% [1.2–15.7]; investigator’s choice of care: 0% [0–6.6]). Similarly, consistent improvement in DCR was observed in patients treated with LUMAKRAS plus Vectibix (95% CI; 960 mg: 72% [57.7–83.2]; 240 mg: 68% [53.7–80.1]; investigator’s choice: 46% [32.6–60.4]). Tumor shrinkage of any level from baseline was observed in 81%, 57% and 20% of patients in the 960 mg dose, 240 mg dose and investigator’s choice cohorts, respectively. The OS was immature at the time of the data cutoff.

About LUMAKRAS/LUMYKRAS (sotorasib)
LUMAKRAS received accelerated approval from the U.S. Food and Drug Administration on May 28, 2021. The supplemental New Drug Application (sNDA) for full approval of LUMAKRAS was accepted by the FDA for standard review and a Prescription Drug User Fee Act (PDUFA) target action date of December 24, 2023, has been set.

About Advanced Colorectal Cancer and the KRAS G12C Mutation
Colorectal cancer (CRC) is the second leading cause of cancer deaths worldwide, comprising 10% of all cancer diagnoses.1 It is also the third most commonly diagnosed cancer globally.2 Patients with previously treated metastatic CRC need more effective treatment options.

KRAS mutations are among the most common genetic alterations in colorectal cancers, with the KRAS G12C mutation present in approximately 3-5% of colorectal cancers.3,4,5

LUMAKRAS (sotorasib) U.S. Indication
LUMAKRAS is indicated for the treatment of adult patients with KRAS G12C-mutated locally advanced or metastatic non-small cell lung cancer (NSCLC), as determined by an FDA-approved test, who have received at least one prior systemic therapy.

This indication is approved under accelerated approval based on overall response rate (ORR) and duration of response (DOR). Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s).

LUMAKRAS (sotorasib) Important U.S. Safety Information
Hepatotoxicity

LUMAKRAS can cause hepatotoxicity, which may lead to drug-induced liver injury and hepatitis.
Among 357 patients who received LUMAKRAS in CodeBreaK 100, hepatotoxicity occurred in 1.7% (all grades) and 1.4% (Grade 3). A total of 18% of patients who received LUMAKRAS had increased alanine aminotransferase (ALT)/increased aspartate aminotransferase (AST); 6% were Grade 3 and 0.6% were Grade 4. In addition to dose interruption or reduction, 5% of patients received corticosteroids for the treatment of hepatotoxicity.
Monitor liver function tests (ALT, AST and total bilirubin) prior to the start of LUMAKRAS every 3 weeks for the first 3 months of treatment, then once a month or as clinically indicated, with more frequent testing in patients who develop transaminase and/or bilirubin elevations.
Withhold, dose reduce or permanently discontinue LUMAKRAS based on severity of adverse reaction.
Interstitial Lung Disease (ILD)/Pneumonitis

LUMAKRAS can cause ILD/pneumonitis that can be fatal. Among 357 patients who received LUMAKRAS in CodeBreaK 100, ILD/pneumonitis occurred in 0.8% of patients, all cases were Grade 3 or 4 at onset, and 1 case was fatal. LUMAKRAS was discontinued due to ILD/pneumonitis in 0.6% of patients.
Monitor patients for new or worsening pulmonary symptoms indicative of ILD/pneumonitis (e.g., dyspnea, cough, fever). Immediately withhold LUMAKRAS in patients with suspected ILD/pneumonitis and permanently discontinue LUMAKRAS if no other potential causes of ILD/pneumonitis are identified.
Most Common Adverse Reactions

The most common adverse reactions occurring in ≥ 20% were diarrhea, musculoskeletal pain, nausea, fatigue, hepatotoxicity and cough.
Drug Interactions

Advise patients to inform their healthcare provider of all concomitant medications, including prescription medicines, over-the-counter drugs, vitamins, dietary and herbal products.
Inform patients to avoid proton pump inhibitors and H2 receptor antagonists while taking LUMAKRAS.
If coadministration with an acid-reducing agent cannot be avoided, inform patients to take LUMAKRAS 4 hours before or 10 hours after a locally acting antacid.
Please see LUMAKRAS full Prescribing Information.

About Vectibix (panitumumab)
Vectibix is the first fully human monoclonal anti-EGFR antibody approved by the FDA for the treatment of mCRC. Vectibix was approved in the U.S. in September 2006 as a monotherapy for the treatment of patients with EGFR-expressing mCRC after disease progression after prior treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy.

In May 2014, the FDA approved Vectibix for use in combination with FOLFOX, as first-line treatment in patients with wild-type KRAS (exon 2) mCRC. With this approval, Vectibix became the first-and-only biologic therapy indicated for use with FOLFOX, one of the most commonly used chemotherapy regimens, in the first-line treatment of mCRC for patients with wild-type KRAS mCRC.

In June 2017, the FDA approved a refined indication for Vectibix for use in patients with wild-type RAS (defined as wild-type in both KRAS and NRAS as determined by an FDA-approved test for this use) mCRC.

INDICATION AND LIMITATION OF USE
Vectibix is indicated for the treatment of patients with wild-type RAS (defined as wild-type in both KRAS and NRAS as determined by an FDA-approved test for this use) metastatic colorectal cancer (mCRC): as first-line therapy in combination with FOLFOX, and as monotherapy following disease progression after prior treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy.

Limitation of Use: Vectibix is not indicated for the treatment of patients with RAS mutant mCRC or for whom RAS mutation status is unknown.

IMPORTANT SAFETY INFORMATION

BOXED WARNING: DERMATOLOGIC TOXICITY
Dermatologic Toxicity: Dermatologic toxicities occurred in 90% of patients and were severe (NCI-CTC grade 3 and higher) in 15% of patients receiving Vectibix monotherapy [see Dosage and Administration (2.3), Warnings and Precautions (5.1), and Adverse Reactions (6.1)].

In Study 20020408, dermatologic toxicities occurred in 90% of patients and were severe (NCI-CTC grade 3 and higher) in 15% of patients with mCRC receiving Vectibix. The clinical manifestations included, but were not limited to, acneiform dermatitis, pruritus, erythema, rash, skin exfoliation, paronychia, dry skin, and skin fissures.
Monitor patients who develop dermatologic or soft tissue toxicities while receiving Vectibix for the development of inflammatory or infectious sequelae. Life-threatening and fatal infectious complications, including necrotizing fasciitis, abscesses, and sepsis have been observed in patients treated with Vectibix. Life-threatening and fatal bullous mucocutaneous disease with blisters, erosions, and skin sloughing has also been observed in patients treated with Vectibix. It could not be determined whether these mucocutaneous adverse reactions were directly related to EGFR inhibition or to idiosyncratic immune-related effects (e.g., Stevens Johnson syndrome or toxic epidermal necrolysis). Withhold or discontinue Vectibix for dermatologic or soft tissue toxicity associated with severe or life-threatening inflammatory or infectious complications. Dose modifications for Vectibix concerning dermatologic toxicity are provided in the product labeling.
Vectibix is not indicated for the treatment of patients with colorectal cancer that harbor somatic RAS mutations in exon 2 (codons 12 and 13), exon 3 (codons 59 and 61), and exon 4 (codons 117 and 146) of either KRAS or NRAS and hereafter is referred to as "RAS."
Retrospective subset analyses across several randomized clinical trials were conducted to investigate the role of RAS mutations on the clinical effects of anti-EGFR-directed monoclonal antibodies (panitumumab or cetuximab). Anti-EGFR antibodies in patients with tumors containing RAS mutations resulted in exposing those patients to anti-EGFR related adverse reactions without clinical benefit from these agents. Additionally, in Study 20050203, 272 patients with RAS-mutant mCRC tumors received Vectibix in combination with FOLFOX and 276 patients received FOLFOX alone. In an exploratory subgroup analysis, OS was shorter (HR = 1.21, 95% CI: 1.01-1.45) in patients with RAS-mutant mCRC who received Vectibix and FOLFOX versus FOLFOX alone.
Progressively decreasing serum magnesium levels leading to severe (grade 3-4) hypomagnesemia occurred in up to 7% (in Study 20080763) of patients across clinical trials. Monitor patients for hypomagnesemia and hypocalcemia prior to initiating Vectibix treatment, periodically during Vectibix treatment, and for up to 8 weeks after the completion of treatment. Other electrolyte disturbances, including hypokalemia, have also been observed. Replete magnesium and other electrolytes as appropriate.
In Study 20020408, 4% of patients experienced infusion reactions and 1% of patients experienced severe infusion reactions (NCI-CTC grade 3-4). Infusion reactions, manifesting as fever, chills, dyspnea, bronchospasm, and hypotension, can occur following Vectibix administration. Fatal infusion reactions occurred in postmarketing experience. Terminate the infusion for severe infusion reactions.
Severe diarrhea and dehydration, leading to acute renal failure and other complications, have been observed in patients treated with Vectibix in combination with chemotherapy.
Fatal and nonfatal cases of interstitial lung disease (ILD) (1%) and pulmonary fibrosis have been observed in patients treated with Vectibix. Pulmonary fibrosis occurred in less than 1% (2/1467) of patients enrolled in clinical studies of Vectibix. In the event of acute onset or worsening of pulmonary symptoms interrupt Vectibix therapy. Discontinue Vectibix therapy if ILD is confirmed.
In patients with a history of interstitial pneumonitis or pulmonary fibrosis, or evidence of interstitial pneumonitis or pulmonary fibrosis, the benefits of therapy with Vectibix versus the risk of pulmonary complications must be carefully considered.
Exposure to sunlight can exacerbate dermatologic toxicity. Advise patients to wear sunscreen and hats and limit sun exposure while receiving Vectibix.
Keratitis and ulcerative keratitis, known risk factors for corneal perforation, have been reported with Vectibix use. Monitor for evidence of keratitis or ulcerative keratitis. Interrupt or discontinue Vectibix for acute or worsening keratitis.
In an interim analysis of an open-label, multicenter, randomized clinical trial in the first-line setting in patients with mCRC, the addition of Vectibix to the combination of bevacizumab and chemotherapy resulted in decreased OS and increased incidence of NCI-CTC grade 3-5 (87% vs 72%) adverse reactions. NCI-CTC grade 3-4 adverse reactions occurring at a higher rate in Vectibix-treated patients included rash/acneiform dermatitis (26% vs 1%), diarrhea (23% vs 12%), dehydration (16% vs 5%), primarily occurring in patients with diarrhea, hypokalemia (10% vs 4%), stomatitis/mucositis (4% vs < 1%), and hypomagnesemia (4% vs 0).
NCI-CTC grade 3-5 pulmonary embolism occurred at a higher rate in Vectibix-treated patients (7% vs 3%) and included fatal events in three (< 1%) Vectibix-treated patients. As a result of the toxicities experienced, patients randomized to Vectibix, bevacizumab, and chemotherapy received a lower mean relative dose intensity of each chemotherapeutic agent (oxaliplatin, irinotecan, bolus 5-FU, and/or infusional 5-FU) over the first 24 weeks on study compared with those randomized to bevacizumab and chemotherapy.
Vectibix can cause fetal harm when administered to a pregnant woman. Advise pregnant women and females of reproductive potential of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment, and for at least 2 months after the last dose of Vectibix.
In monotherapy, the most commonly reported adverse reactions (≥ 20%) in patients with Vectibix were skin rash with variable presentations, paronychia, fatigue, nausea, and diarrhea.
The most commonly reported adverse reactions (≥ 20%) with Vectibix + FOLFOX were diarrhea, stomatitis, mucosal inflammation, asthenia, paronychia, anorexia, hypomagnesemia, hypokalemia, rash, acneiform dermatitis, pruritus, and dry skin. The most common serious adverse reactions (≥ 2% difference between treatment arms) were diarrhea and dehydration.
To see the Vectibix Prescribing Information, including Boxed Warning visit www.vectibix.com.