“Immunotherapy may represent an effective new treatment approach for relapsed mesothelioma patients, according to a new study.
“Anti–programmed death-1 (PD-1) immunotherapy may have activity as second- or third-line therapy in malignant pleural mesothelioma (MPM), an aggressive, rare cancer associated with asbestos exposure that has no curative treatment. All MPM patients relapse despite initial chemotherapy, and median overall survival (OS) is 9 months at most, said lead author Arnaud Scherpereel, MD, PhD, head of the pulmonary and thoracic oncology department at the University Hospital (CHU) of Lille in Lille, France, at a press briefing at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting (abstract LBA8507).”
“Nivolumab plus ipilimumab demonstrated an intracranial response (ICR) rate of 42% in asymptomatic patients with melanoma brain metastases who had not received prior local therapy to the brain.
“In the phase II Anti-PD1 Brain Collaboration (ABC) trial, the 6-month intracranial PFS rate was 46% with the anti–PD-1/CTLA-4 combination.
” ‘The combination of nivolumab and ipilimumab has high activity in melanoma brain metastases and may be considered for upfront therapy in such patients,’ said lead author Georgina V. Long, BSc, PhD, MBBS, clinical researcher at the Melanoma Institute Australia and Westmead Hospital in Sydney.”
UCLA’s Jonsson Comprehensive Cancer Center | May 25, 2017
“A new study by UCLA scientists has found that the breakthrough immunotherapy drug pembrolizumab can be more effective in improving survival in people with non-small cell lung cancer (NSCLC) if they have previously received radiation therapy, compared to those without a history of radiation treatment. The findings are important as the strategies of combining radiation therapy with anti-PD-1 antibodies such as pembrolizumb are currently being explored, and have the potential to increase the overall benefit of immunotherapy for people with NSCLC, the most common form of lung cancer.”
“Seasonal influenza vaccination resulted in increased risk of immune-related adverse events (AEs) in lung cancer patients treated with PD-1/PD-L1 checkpoint inhibitors in a small study. However, the risks of the flu itself may still outweigh the risks associated with vaccination.
” ‘Use of immune checkpoint inhibitors is now standard clinical practice for many oncology patients, and these same patients—particularly those with lung cancer—also face increased risk for complications from influenza,’ said Sacha Rothschild, MD, PhD, of University Hospital Basel in Switzerland, in a press release. ‘Although routine influenza vaccination has long been recommended for cancer patients, there are concerns that it might trigger an exaggerated immune response in this subgroup receiving checkpoint inhibitors.’ ”
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.
Now, the pressing questions are: Why do these drugs not work for all patients? How can doctors select which patients should be treated with different types of drugs (targeted versus immune checkpoint versus intralesional)? And how can doctors identify patients who may benefit from a combination of different drugs?
BRAF-mutant melanoma: targeted drugs
Getting a positive test for the BRAF V600 tumor mutation is certainly good news for a newly diagnosed melanoma patient. This is because some targeted drugs work very well against such tumors, which account for about 50% of melanomas.
The drugs vemurafenib or dabrafenib, which attack tumors by inhibiting mutant BRAF proteins, are no longer used on their own because combining them with MEK inhibitors (cobimetinib and trametinib, respectively) works so much better. The percentage of patients who respond to combined BRAF/MEK inhibition is about 70% or higher, and durable complete responses were observed in about 19% patients with stage IV or unresectable stage III melanoma in three large clinical trials that tested these combinations. The results of treatment with dabrafenib and trametinib in patients with resectable stage III melanoma were particularly impressive. One hundred percent of these patients had no relapse within the first six months after treatment, compared to just 28% of those treated with standard chemotherapy. All patients had fewer than three metastatic sites.
That last point brings us to an important question: Which stage IV patients with BRAF-mutant (BRAF+) melanoma may need a combined treatment with targeted and immunotherapy (immune checkpoint) drugs?
It is becoming clear that stage IV patients who have fewer, less bulky metastases (lower tumor burden) do much better on BRAF/MEK-targeting drugs. High blood levels of a protein called LDH has long been recognized as a poor prognostic factor in melanoma, and it has not lost its grim significance in the era of targeted and immunotherapy drugs. Patients with high LDH and many metastatic tumors may need a combined treatment with BRAF/MEK inhibitors and immune checkpoint drugs.
So far, combination treatments have proven to be efficacious in patients with high tumor burden. The problem is that combining BRAF/MEK inhibitors with immune checkpoint drugs of the type known as anti-PD-1 increases side effects (toxicity) in quite a dramatic way. The Keynote 022 clinical trial—which combined the anti-PD-1 drug pembrolizumab with dabrafenib and trametinib in a small group of patients—reported that 40% experienced serious side effects (grade 3–4), and close to 30% discontinued treatment. A response rate of 60% was observed but remains to be confirmed.
A very similar rate of side effects was observed in a trial that combined atezolizumab (another immune checkpoint drug of the type known as anti-PD-L1) with vemurafenib and cobimetinib. On a highly positive note, 83% of the patients in this trial responded to the treatment, with 10% going into complete remission. An earlier study of durvalumab (also anti-PD-L1) with dabrafenib and trametinib saw responses in 69% of patients.
Several trials have also addressed the possibility of sequential treatment with two different types of drugs in order to address the problem of toxicity.
Immune checkpoint drugs across the molecular subtypes
Immune checkpoint drugs may also be effective in tumors with mutations other than BRAF, including a mutation in the NRAS gene (NRAS+). Data are being accumulated for patients receiving the FDA-approved immunotherapy drugs nivolumab or pembrolizumab (both anti-PD-1 drugs). It appears that 47% of patients receiving nivolumab survive for three years, and 48–49% of those receiving pembrolizumab survive for 2 years (pembrolizumab data have not yet reached the 3-year point). Combination of nivolumab and ipilimumab (a type of immune checkpoint drug known as an anti-CTLA4 antibody) could eventually produce better results, but at the cost of a much higher toxicity. It is a bit difficult to say if these data are similar for BRAF+ and BRAF-/NRAS+ melanoma patients receiving immune checkpoint drugs, because most patients with BRAF+ cancers receive targeted drugs.
Patients whose tumors test positive for an NRAS mutation (NRAS+) but not for a BRAF mutation (BRAF-) certainly have fewer treatment options than those whose tumors are BRAF-positive. NRAS mutations are encountered in about 20% of melanomas, and there are no effective targeted drugs for this subgroup. The only targeted drug that has shown promise in NRAS+ melanoma is binimetinib, a MEK inhibitor. In a trial for patients who were either untreated or had not responded to immune checkpoint drugs, binimetinib produced responses in 45% of patients; of those receiving only dacarbazine, a standard chemotherapy, just 9% responded. However, binimetinib prolonged overall survival by just 1.3 months compared to dacarbazine—not exactly an impressive improvement, which is apparently why the manufacturer of binimetinib withdrew its application for FDA approval of the drug.
Other trials are testing immune checkpoint drugs combined with MEK inhibitors for patients whose melanomas have no BRAF mutations (of which a substantial proportion have mutated NRAS). No results of these trials have yet been reported. Meanwhile, a very small study reported a response rate of 45% to combination of atezolizumab (anti-PD-L1) and cobimetinib in BRAF- melanoma patients. Additional trials testing durvalumab or pembrolizumab with trametinib have not posted results yet.
Regardless of specific tumor mutations, much hope lies in the clinical exploration of combinations of drugs that activate the immune system in different ways. Numerous immune checkpoint drugs work by activating the immune system. However, unlike the anti-PD-1 and anti-CTLA4 drugs discussed above, which remove inhibitory signals from the immune system’s T cells so they can attack cancer cells, newer drugs actually activate T cells by binding to positive regulatory proteins on these cells. Other new drugs aim to eliminate inhibitory signals created in the tumor microenvironment, such as those produced by different types of inflammatory cells or regulatory T cells. I would refer the interested reader to this excellent overview of these new drugs, which are now being tested against metastatic melanoma in numerous phase I trials.
“Statistical modeling of long-term survival from the KEYNOTE trials of the programmed cell death protein 1 (PD-1)–inhibitor pembrolizumab (Keytruda) estimates that one-quarter of appropriately selected patients with advanced non–small cell lung cancer (NSCLC) may attain long-term survival.
” ‘In the context of the pembrolizumab program, these are the furthest-out data that we have so far, and I think they represent a remarkable step forward,’ commented Matthew D. Hellmann, MD, of Memorial Sloan Kettering Cancer Center, New York, who presented the analysis at the 2017 ASCO-SITC (Society for Immunotherapy of Cancer) Clinical Immuno-Oncology Symposium.”
With a few exceptions, glioblastoma (GBM) remains largely incurable, and the U.S. Food and Drug Administration (FDA) has approved few treatments for the disease. Surgery (when feasible), radiation, and temozolomide are used in most patients. But even if a newly diagnosed tumor can be surgically excised, recurrences are too common.
In this blog post, I simply list some of the new treatments available in clinical trials for GBM and other high-grade brain tumors. Only drugs that have at least some preliminary results of activity are included, and the list is not meant to be fully comprehensive. The interested reader can judge for herself what might be of interest, keeping in mind that no single treatment is suitable or will work for all GBM patients. Continue reading…
“UCLA scientists have discovered that people with cancers containing genetic mutations JAK1 or JAK2, which are known to prevent tumors from recognizing or receiving signals from T cells to stop growing, will have little or no benefit from the immunotherapy drug pembrolizumab. This early-stage research has allowed them to determine for the first time why some people with advanced melanoma or advanced colon cancer will not respond to pembrolizumab, an anti-PD-1 treatment.
“The study, led by Dr. Antoni Ribas, director of the UCLA Jonsson Comprehensive Cancer Center Tumor Immunology Program, also found that JAK1 or JAK2 genetic mutations led to a loss of reactive PD-L1 expression. PD-L1 is an immune biomarker expressed on tumor cells and pembrolizumab requires an abundance of it to effectively attack cancer cells.”
In spring of 2014, Peter Fortenbaugh noticed what appeared to be a tick that had bitten his lower calf. “It turned out not to be a tick, but it didn’t really go away,” he says.
The spot began to grow and bulge, and in October, Peter showed it to his primary care doctor, who referred him to a dermatologist to remove it. At the time, Peter recalls, it did not occur to him that the growth could be serious.
“I was actually very concerned about skin cancer because I spent a lot of time out in the sun sailing,” Peter says. “I put on a tremendous amount of sunscreen and protection, but never on my legs…I never connected the dots.”
However, a biopsy of the growth came back positive for melanoma. Peter, who lives in Palo Alto, California, with his wife and three children, immediately reached out to several doctors in the San Francisco Bay Area, and all had the same advice: “Take it out, take a biopsy.” Continue reading…