The Trouble With KRAS


Mutations in the gene that encodes the KRAS protein are frequently encountered in various human cancers. They are found in about 30% of non-small cell lung cancers (NSCLCs), making KRAS the single most common gene mutated in this cancer. The rate of KRAS mutations in other cancers, such as pancreatic or colorectal, is even higher.

A mutant KRAS protein that is always in the “on” position activates many signaling pathways, many of which lead to unrestrained growth and proliferation of cancer cells. This makes KRAS an appealing treatment target. However, challenges abound, and researchers are exploring several different approaches to treating KRAS-mutant cancers.

Unlike mutations in proteins known as receptor tyrosine kinases, like EGFR or ALK, mutated KRAS is a very difficult protein to target with cancer drugs. (So much so that the National Institutes of Health (NIH) has undertaken a special effort to intensify the effort towards successful targeting of mutant KRAS, known as the RAS Initiative.) Continue reading…


Metastatic Melanoma: Not Quite Curable…But Getting There


By 2050, the number of deaths due to malignant melanoma in the U.S. could be three times lower than peak levels reached before 1960. Researchers presented the data behind this prediction at the 2017 European Cancer Congress in January.

It is unclear how much of this anticipated decline in deaths can be attributed to the availability of new, effective treatments. However, it is obvious that much-increased awareness of sunlight exposure as the single factor most responsible for the development of skin melanoma has contributed to lower incidence of the disease.

In any case, the armament of treatments available for metastatic melanoma is currently such that this diagnosis has transformed from being almost universally fatal (even just a few years ago) into a being largely treatable. Since 2011, the U.S. Food and Drug Administration (FDA) has approved eight new drugs for melanoma. Continue reading…


Melanoma: New Drugs and New Challenges (Part 2 of 2)


Editor’s note: This is part 2 of a 2-part post on the latest research in melanoma. To learn about research into drug combinations for melanoma that may work better than single drugs, check out Melanoma: New Drugs and New Challenges (Part 1 of 2).

As always, the more new treatments become available in melanoma, the more new challenges arise. With eight new drugs approved for melanoma in the last five years, oncologists may sometimes face the difficult choice of what drugs to choose for a patient’s first-line treatment. Immune checkpoint drugs sometimes cause serious side effects, but progress is being made on how to treat these and also how to treat patients with pre-existing autoimmune conditions. New approaches are needed in efforts to prevent recurrence of melanomas diagnosed at earlier stages of disease progression. These and other challenges are discussed below. Continue reading…


AstraZeneca Provides Update on Phase III Trial of Selumetinib in Non-Small Cell Lung Cancer

Excerpt:

“AstraZeneca today announced results from the Phase III SELECT-1 trial of the MEK 1/2 inhibitor, selumetinib, in combination with docetaxel chemotherapy as 2nd-line treatment in patients with KRAS mutation-positive (KRASm) locally-advanced or metastatic non-small cell lung cancer (NSCLC).

“The results showed that the trial did not meet its primary endpoint of progression-free survival (PFS), and selumetinib did not have a significant effect on overall survival (OS). The adverse event profiles for selumetinib and docetaxel were consistent with those seen previously.”

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Melanoma: New Drugs and New Challenges (Part 1 of 2)


New targeted and immunotherapy drugs have changed the diagnosis of metastatic melanoma from a death sentence into a disease that can potentially be managed and even cured. Nevertheless, these new drugs do not work in all patients, or they may stop working after a transient response. This post (part one of two) will describe ongoing efforts to find drug combinations with higher efficacy than single drugs and decipher the mechanisms underlying drug resistance. Continue reading…


Oxnard Explains Role of BRAF in NSCLC

Excerpt:

“Geoffrey R. Oxnard, MD, specializes in researching molecular mutations in non–small cell lung cancer (NSCLC) with a particular emphasis on prognostic and predictive biomarkers. Oxnard, who is an assistant professor of Medicine at Harvard Medical School and a thoracic oncologist at the Dana-Farber Cancer Institute, spoke with Targeted Oncology about the potential for BRAF-targeting therapies in NSCLC.

“TARGETED ONCOLOGY: What is the potential for utilizing currently available BRAF/MEK-targeted therapies in treating patients with NSCLC?

“Oxnard: Combination BRAF/MEK inhibitor therapy is a very compelling approach because combinations of BRAF and MEK inhibitors have clearly been shown to improve response rates and overall survival in melanomas harboring BRAF V600E mutations when compared with single-agent BRAF inhibition.”

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Distinct Features Associated With Benefit for BRAF/MEK Inhibition

Excerpt:

“With the development of novel targeted and immunotherapeutic agents that are more efficacious than traditional chemotherapy, treatment paradigms in melanoma have undergone major changes. Current recommendations for first-line systemic therapy for patients with advanced or metastatic melanoma consider BRAF mutation status, tumor growth rate, and the presence or absence of cancer-related symptoms.

“Immunotherapies with agents that block CTLA-4 or PD-1/PD-L1 checkpoints have been associated with durable responses in a subset of patients, and are often considered for patients with low-volume, asymptomatic metastatic melanoma. Targeted therapies, on the other side, are preferred for patients with BRAF-mutant tumors who have symptomatic disease and benefit from the rapid response associated with these agents.”

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Targeted Therapy Combinations Still Key in Metastatic Melanoma

“Combinations of targeted therapies continue to advance toward full regulatory approval for patients with metastatic or unresected melanoma, given the substantial benefits seen with these agents. At this time, the FDA is considering two applications for separate combinations of BRAF and MEK inhibiting agents for patients with unresectable or metastatic BRAFV600 mutation-positive melanoma.

“ ‘The future of the treatment of melanoma is clearly going to be in combinations, both for targeted therapy and for immunotherapy,’ said Jeffrey S. Weber, MD, PhD, who recently joined the NYU Langone Medical Center. ‘Already, there is an FDA-approved combination therapy that is targeted; that is dabrafenib and trametinib. There are new combinations coming up, mainly concerning CDK 4/6 and MEK inhibitors in NRAS-mutated but BRAF wild-type melanoma, which is an unmet medical need.’ “


Pembrolizumab Increases Progression-Free Survival vs Chemotherapy in Ipilimumab-Refractory Advanced Melanoma

“In a randomized phase II KEYNOTE-002 trial reported in The Lancet Oncology, Ribas et al found that treatment with the anti–PD-1 antibody pembrolizumab (Keytruda) prolonged progression-free survival vs investigator-choice chemotherapy in patients with advanced melanoma progressing on ipilimumab (Yervoy) and, if BRAF V600 mutant–positive, a BRAF or MEK inhibitor.

“The open-label trial included 540 patients from 12 countries with progressive disease within 24 weeks after two or more ipilimumab doses and, if BRAF V600 mutant–positive, previous treatment with a BRAF or MEK inhibitor or both. Patients were randomly assigned 1:1:1 between November 2012 and November 2013 to receive pembrolizumab 2 mg/kg (n = 180) or 10 mg/kg (n = 181) every 3 weeks or investigator-choice chemotherapy (n = 179, including 42 to paclitaxel plus carboplatin, 28 to paclitaxel, 13 to carboplatin, 45 to dacarbazine, and 43 to temozolomide)…

“The investigators concluded: ‘These findings establish pembrolizumab as a new standard of care for the treatment of ipilimumab-refractory melanoma.’ “