Check-point charlie

Barts-MS rose-tinted-odometer ★★★★★ 

The argument about whether or not MS is primarily a T-cell or B-cell disease is academic. Almost all the data suggests that both cell types are involved. Clinical trial data also suggests MS outcomes when it comes to end-organ damage (brain volume loss) is superior for therapies that target both  T and B cells, i.e. alemtuzumab and HSCT over say mainly B-cell therapies (rituximab, ocrelizumab, ofatumumab and cladribine). I have posted on the latter topic in the past, i.e. see ‘Beyond NEDA’. 

Another big clue is worsening MS and new-onset MS after the treatment of cancer with the relatively new class of treatments called immune checkpoint inhibitors (ICI). These drugs target cell surface receptors that inhibit T-cell activation. Remove the inhibition and you lower the threshold for T-cell activation. About 50% of patients treated with ICI develop immune-mediated complications including new-onset MS. 

The study below identifies 14 cases of MS after ICI, which I suspect is just the tip of the iceberg. The type of MS induced by ICI appears to be much more aggressive in onset and disease course. Why? I suspect because the activated T-cells are not being regulated as a result of ICI  treatment. 

I am aware that some people argue that these cases don’t represent true MS, but a different disease. I don’t agree. Why? There is an increasing number of people with established MS who develop malignancies requiring treatment with ICI.  In many of these cases, ICI triggers major relapses and rebound disease activity. The sceptics can’t really argue that these patients don’t have MS. 

The use of ICI in patients with established MS is creating a treatment dilemma. They clearly need the ICI to treat their cancer, but how do you manage their MS during the high-risk period when they are on ICI? 

I recently recommended that a patient with MS who had disseminated bowel cancer and was about to start an immune checkpoint inhibitor go onto natalizumab despite being JCV positive to prevent exacerbation of her MS. The rationale being that the polyclonal activation of her T-cells in the periphery, including her autoimmune cells responsible for her MS, would not traffic to the brain and spinal cord and cause an MS relapse. The potential downside of this strategy is that if she had occult secondaries in her CNS and gut, areas of the body that natalizumab reduced lymphocyte trafficking, natalizumab will prevent her activated T-cells finding and clearing cancer cells in these organs. As bowel cancer rarely metastasizes to the CNS we thought this was a risk worth taking. 

The last update I had about this patient was that she was doing well from the MS perspective (natalizumab is a very effective DMT), but she was not doing that well in relation to her bowel cancer. She, unfortunately, had liver metastases that had not responded as hoped to the ICI. 

I am also sure that natalizumab will prevent the CNS complications associated with CAR-T cell therapies. Could this be a repurposing opportunity for natalizumab? I have informed Biogen about this possibility. 

So in conclusion, don’t let anyone try and convince you that MS is only a B-cell disease. It is a T-cell and B-cell disease and we are really lulling ourselves into a false sense of security by thinking anti-B-cell monotherapy is sufficient to treat MS. The anti-B-cell therapies may appear very effective and safer in the short term, but as a class, their impact on brain volume loss (end-organ damage) is just not good enough for me (see NEDADI post). This is why we need to think about using anti-B-cell therapies differently, i.e. as part of an induction-maintenance strategy or in combination with other therapies that target other disease processes. 

Garcia et al. Multiple Sclerosis Outcomes After Cancer Immunotherapy. Clin Transl Oncol, 21 (10), 1336-1342 Oct 2019. 

Introduction: Neurological immune-related adverse events are a rare but potentially deadly complication after immune checkpoint inhibitor (ICI) treatment. As multiple sclerosis (MS) is an immune-mediated disease, it is unknown how ICI treatment may affect outcomes.

Methods: We analyzed the United States Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database for pembrolizumab, atezolizumab, nivolumab, ipilimumab, avelumab, and durvalumab 2 years prior their FDA approval until December 31, 2017, to include all cases with confirmed diagnosis/relapse of MS. We also included cases reported in the literature and a patient from our institution.

Results: We identified 14 cases of MS with median age of presentation of 52 years. Indications for ICI included melanoma in 7 (36.36%) cases, non-small cell lung carcinoma in 2 (18.18%) cases, 1 case (9.09%) each of pleural mesothelioma, renal cell carcinoma, and colorectal cancer, and unreported in 2 (18.18%) cases. History of MS was confirmed in 8 (57.1%) cases. Median time to beginning of symptoms was 29 days with rapid disease progression; two patients died due to their relapse. Median time for symptom resolution was 8 weeks. Outcomes did not vary by comparing CTLA-4 and PD-1/PD-L1 inhibitors.

Conclusions: Reported MS relapses after ICI are rare, but the adverse events described include rapid neurologic progression and death. Larger and prospective studies are warranted to assess disability and long-term outcomes and outweigh the risks of starting immunotherapy in patients with MS.

CoI: multiple

To T or not to T (2)

Prof G what happens to MS disease activity if you stimulate T-cells?

About 2 years ago I attended a grand round during which a patient with a history of RRMS had had a catastrophic relapse after receiving ipilimumab for metastatic melanoma. The patient has a massive brain stem relapse and her MRI showed multiple Gd-enhancing lesions with several pseudotumoral lesions. She was in a bad way. Interestingly, this case was not unique as a very similar case had been published. In addition, there are series of other examples of ipilimumab and other immune checkpoint inhibitors exacerbating and/or triggering autoimmune diseases including an MS-like disease. I say MS-like because we don’t know for sure if these cases will turn out to have classic MS on biopsy, or at post-mortem, to prove they have definite MS according to a conventional definition of the disease.

Ipilimumab belongs to the class of drugs called ‘checkpoint inhibitors’ that are designed to remove one of the immunological brakes that control T-cell activation. Ipilimumab is one of many T-cell stimulants that have revolutionised the care of patients with various different cancers. Ipilimumab is a very smart drug it blocks CTLA-4, a cell surface molecule on T cells, which normally blocks or downregulates T cell activation when it binds to CD80 and CD86 on antigen-presenting cells. Ipilimumab enhances the anti-tumoral response while increasing the likelihood of autoimmunity.

So what has this really got to do with MS? Well, these cases are telling us in a not so subtle way that by stimulating T-cells we can exacerbate MS. In other words, T-cells are probably still active in established MS. What this experiment is not telling us is which population of T-cells is the culprit as CD4+, CD8+ and T-regulatory cells express CTLA-4 and are hence affected by Ipilimumab. Nor is it telling us about the APC side, which APC is stimulating the T-cells. Is it the B-cell, the macrophage/microglia or another APC?

The moral of this story is that it takes two to tango; the T-cell and its APC. The question is which APC is the preferred partner for the T-cell in MS. Based on the evidence the B-cell seems to be the dominant partner, but who knows in the presence of peripheral B-cell depletion other less dominant partners may take to the floor.

Gettings et al. Severe relapse in a multiple sclerosis patient associated with ipilimumab treatment of melanoma. Mult Scler. 2015 Apr;21(5):670.

56-year-old male, diagnosed in December 1997 with RRMS. Treated with glatiramer acetate in February 1998. Relatively good response to GA with only sensory relapses. In 2005 methotrexate was added. His MS stabilized and he was free of relapses from 2005 to 2013 with a slight increase in disability from an Expanded Disability Status Scale (EDSS) score of 1 to 1.5. In September 2009 diagnosed with melanoma. He had a recurrence in November 2012 with metastases to soft tissue and lymph nodes. He was started on ipilimumab. Methotrexate and glatiramer acetate were stopped prior to initiating ipilimumab. Within one month, he presented with subacute onset of left lower extremity hemiparesis, gait dysfunction and ataxia. An MRI revealed a new left centrum semiovale enhancing lesion consistent with active demyelination. His symptoms improved with high dose methylprednisolone. Ipilimumab was continued. In May 2013 he was readmitted for transient left-sided weakness and ataxia. MRI revealed an enhancing lesion in the right corona radiata. Follow-up imaging revealed a second enhancing lesion in the right frontal lobe and he was restarted on glatiramer acetate and steroids.