We’ve been waiting for this all year, right, this bright spot in a sea of dread? Nothing perks me up like the latest in metastatic breast cancer research.
My abstract highlights – including new results on DS-8201, tucatinib, the accursed entinostat and a novel Pfizer ADC plus my predictions for late-breaking abstract results – after the break.
Continue reading “News from ASCO Abstract Day”Little tucatinib is all grown up! The TKI that started out at Array long, long ago has now been FDA approved in combination with Herceptin and Xeloda for the treatment of 2L+ HER2+ metastatic breast cancer. Additional international approvals could be imminent, as the submission was part of a concurrent review program between the FDA and worldwide regulatory authorities. This is fantastic news for everyone but the Kadcyla sales force, though Genentech will get a slice of the pie via some incremental Xeloda sales.
The approval was supported by data from the HER2CLIMB trial, which enrolled 612 subjects and randomized them 2:1 to tucatinib or placebo plus Herceptin and Xeloda. Subjects with brain mets at baseline comprised 47.5% of the study population. This is their story:
Among subjects with measurable disease at baseline, the confirmed objective response 40.6% in the tucatinib group and 22.8% in the placebo group. But look at those numbers! The brain mets patients didn’t do much worse than patients with visceral mets. Cascadian went in boldly by enrolling brain mets patients, and the gamble paid off. They have brain mets featured prominently in their labeling, and they’re an example for all the companies that have excluded brain mets patients from their trials for fear of muting response rates. But patients in the real world, in HER2+ breast cancer, have brain mets. I have brain mets. I’ve looked at a lot of eligibility criteria, and while we’ve seen brain mets exclusions gradually relax over the past decade, most trials that allow them still caution that they must be stable.
Cheers to you, Cascadian/SeaGen.
The one thing I said I would never do is whole brain radiation. Never, ever. That was the line. I was too scared of cognitive decline, that I wouldn’t be able to write, talk, walk or remember, and there is so much good stuff to remember.
I was diagnosed after going to the ER with a seizure that could be more gently characterized as episodes of visual changes. At intake, it was about 9 p.m. I insisted to the nurses and everyone who came by that I almost certainly had brain mets, but I still had to wait until after 3 a.m. for retinal detachment to be ruled out before they would put me on the list for an MRI. The ER was mobbed, and I spent the night on a stretcher in a hallway, using my coat as a blanket. I had an MRI the next morning, and while I was on the scanner I missed a call from my boss. Good remote employee that I am, this caused my heart to pound more than the impending test results. I kept muting and unmuting myself so he wouldn’t hear the sounds of the ER around me. This was actually the most surreal part of the day. The brain mets were known, as far as I was concerned; I didn’t know how I was going to explain them.
After the scan, they moved me out of a hallway and into an exam room, and some poor innocent ER resident came in and pulled my MRI up on a computer. I could see a handful of lesions, pretty big ones, but I couldn’t get a good look because the guy was clearly accustomed to looking at X-rays of fractures and lungs and not to scrolling through slices. So I didn’t see any of the other slices, but it seemed like the size of at least one of the lesions was pushing what could be managed with SRS, which as a treatment modality of course seemed comparably benign, and I’d have no objection to using it. I didn’t have a death wish with the brain mets, just an aversion to WBR.
They topped me up with Ativan and a massive dose of steroids and instructed me to go to my clinic, go straight there, right now, and I agreed. We stopped at the house so I could take a shower and put on makeup and change into nice clothes because I wasn’t facing The Institute looking like I’d just suffered a few hours of intermittent seizure activity then spent the night in a hallway before being told I had multiple brain mets.
The main thing I learned from that first meeting was that it was a lot more than three lesions. It was probably closer to a dozen. Hopefully that ER guy has since learned to scroll. When we were alone again, I told my husband that if they wouldn’t do SRS there, and we couldn’t find another institution to do it, and I couldn’t get tucatinib, that would be it. I was calling it.
I was ready for all of this, because I’d been having symptoms. The main one being confusion with bright lights at night; I couldn’t seem to see dimension when there were headlights and streetlamps competing for attention.
Why didn’t I say anything? Because it felt like only brain mets could, ahem, bring me down. I wasn’t having it.
Months earlier, I had bought ELO tickets for me and my father. My dad shaped my deep love for oldies and classic rock from when I was an infant, and I remember listening to Face the Music on his turntable when I was 8 or 9. He saw them live a couple of times in the 70s, but anyone who knows the band knows that Jeff Lynne’s not a never-ending tour guy, and I didn’t think I’d get a chance to see him in my lifetime. I was happy to take more or bigger mets in exchange for that night. What was I going to do, get a scan and start treatment and jeopardize the concert? I waited 10 years for the brain mets, but I’d been waiting for Jeff Lynne all my life.
It was so worth it. It was one of the best nights of my life. I think my dad feels the same. Of course I never told him that I was waiting out brain mets so we could have that time together.
This is going somewhere, as much as any of my anecdotes go anywhere. When I met my radiation oncologist, he told me WBR was my best option. Number of lesions aside, the size of the lesions alone was likely to cause so much fibrosis that I may suffer more symptoms than I was having already, and it would make follow-up challenging. All I asked about was the risk of cognitive decline. His answers were good, all of them. He had stories about patients who had better outcomes than I imagined to be possible. I started to consider WBR. He seemed worried that I wasn’t processing the rest of it, like the fact I had a little army of brain mets capsizing some essential brain function. You’ll lose your hair, he warned. He showed me the Paul Brown papers on hippocampal-sparing WBR in combination with memantine. WBR became the reasonable option.
It raised a question I’d never asked before in course of my treatment, because I was always so sure I would do well: what if I didn’t deteriorate?
I didn’t. A year out, and it’s like nothing happened. I compromised everywhere here, from when I reported the brain mets symptoms to the treatment itself. Maybe it cost me, and it could cost me more later (I’ve likely exhausted most options for further brain radiation). But I did what I wanted, and my brain and mobility and independence are intact. It reassures me whenever I think about it that I’m capable of staying true to myself when it counts.
This is not the kind of blog I usually write. Drugs and science are really the only things I want to talk about. But I wanted to tell this story so that other patients know good outcomes are possible. Think about where we were with HER2+ brain mets when I started, when even without the brain mets, I felt like I was on a precipice, always pushing up against the limits of treatment. There was no space for risk. Waiting to see if Tykerb and Xeloda would be effective was one of the only times I ever felt like a patient. I didn’t know then how many rules I’d have to break to stay myself, to get what I needed.
Now it’s 2020, and I can’t even count the lines of therapy I’ve had. I just started DS-8201. We’ll check in on the HER2+ pipeline in a future entry.
Puma’s announcement on Monday that they hit one of their two primary endpoints in NALA is one of the more opaque press releases I’ve seen in a while, reporting a statistically significant PFS benefit for neratinib + capecitabine versus lapatinib + capecitabine, an OS benefit that did not reach significance and a statistically significant benefit in a secondary endpoint of “time to intervention for symptomatic central nervous system disease.” The latter endpoint is the one I most want to be meaningful because CNS was always the most compelling use case for this drug, and wouldn’t it be great if neratinib actually helped someone? Even when you squint, though, there’s not much to be encouraged by in these results, and this is a company press release.
NALA is a phase III randomized study concocted on the whim of becoming third-line SOC in HER2+ metastatic breast (after THP and T-DM1), despite the fact that DS-8201a and, more relevantly for CNS mets, tucatinib have made considerably stronger moves to claim that spot. (DS-8201a is going after second-line, and we know nothing about the drug’s activity in CNS disease; tucatinib has focused on CNS.) There is nothing in Monday’s press release to suggest that neratinib has a credible claim to the third-line spot; a PFS edge over lapatinib + cape is nothing to write home about, and most patients in the 3L setting would likely prefer a trial or a more compelling Herceptin cocktail (more on the absence of Herceptin below), over neratinib + cape. This is not going to be the standard third line for visceral disease. That means we’re left with a CNS opportunity, which is a sad slice of the HER2+ market opportunity and, importantly, not all that different from what’s available now via guidelines. Since all we’ve seen from NALA so far are delays attributed to a slow rate of mortality events, with no info about the patient mix, there’s not much to build confidence in the validity of this benefit. It would be nice to know how many patients are in the CNS analysis, especially since the time to CNS intervention measure is just a secondary endpoint. There might not be anything here, and until we have tucatinib, Tykerb is just so much easier. Plus, in regular clinical use, you get Tykerb with Herceptin.
The NALA comparator is infuriating, because it’s not real-world standard of care; no one drops Herceptin, and this is one of the reasons I love the Cascadian study; HER2CLIMB’s experimental arm gets tucatinib + Herceptin + cape. The triplet makes sense, has positive signal from a published phase Ib study and aligns with practice in that everyone gets Herceptin. (It’s like they had a market strategy or something, like they were planning to be the TKI of choice in HER2+ brain mets.) We have no evidence that neratinib will perform better than the true SOC, and with the toxicity, why guess? Why put that on the market in such a competitive environment? The evidence we do have trades QOL not for OS, but for imaging results, and it’s just not good enough.
Actual data was promised sometime in 2019.
With Mersana struggling to dig its way out of the pain of a clinical hold, it seemed like a good time to check in on the many antibody-drug conjugates (ADCs) in development in metastatic breast cancer. T-DM1 made it look so easy.
| Sponsor | Target | Payload | Status | |
| T-DM1 | Genentech | HER2 | DM1 (maytansinoid) | Approved |
| Sacituzumab govitecan (IMMU-132) | Immunomedics | TROP2* | SN-38 (irinotecan metabolite) | Phase 3 |
| Trastuzumab deruxtecan (DS-8201a) | Daiichi Sankyo | HER2 | Exatecan derivative | Phase 3 |
| SYD985 | Synthon | HER2 | Duocarmycin | Phase 3 |
| XMT-1522 | Mersana | HER2 | AF-HPA (auristatin) | Phase 1b |
| Ladiratuzumab vedotin (SGN-LIV1A) | Seattle Genetics | LIV-1* | MMAE (auristatin) | Phase 1 |
| ARX788 | Ambrx | HER2 | MMAF (auristatin) | Phase 1 |
| Glembatumumab vedotin | Celldex | GPNMB | MMAE (auristatin) | Discontinued at P2b (METRIC) |
Development-stage drugs bookended with T-DM1 and Celldex, since they’re referenced in this blog; asterisk if Sponsor claims you don’t need confirmed expression of the marker to benefit from the drug.
Mersana was put under a partial clinical hold in July when a patient died on-study. The hold was lifted two months later with some protocol changes – “increased monitoring”, more limitations on hepatic function for future subjects and a new dosing schedule, with the drug being administered every four weeks instead of every three. The ClinicalTrials.gov status is still active, not recruiting, and they haven’t updated the enrollment criteria or dosing schedule yet. So, as the stock will attest, we’ve heard nothing good about XMT-1522 so far, only bad, but I’m not totally horrified by the safety signal this early. Mostly because this is a heterogenous population in something of a baby basket trial. They’re enrolling the traditional HER2+ MBC cohort, which is, generally, a pretty healthy bunch – but they’ve also got HER2-low MBC, HER2+ gastric and HER2 mutated or overexpressed NSCLC cohorts. The mix as of June was 18 breast patients (HER2 status unspecified), 3 gastric patients (again, no HER2 detail) and 1 HER2-amplified gallbladder patient. There’s some unpredictability there, and likely variation in clinical status.
Would I enroll? No way. The drug is too weird. I don’t want a “novel HER2 antibody”. Mersana says their antibody attaches to a different HER2 epitope than Herceptin and Perjeta; that’s about all we know about it. They’ve also developed a novel binding technique and aren’t using a traditional linker. Too many variables, guys. If you want patients to enroll in a phase 1, at least make them feel like they’re getting some Herceptin. Daiichi and Synthon have an antibody that is virtually identical to trastuzumab, and that strikes me as exactly right; leave the uncertainty to the linker. For what it’s worth, trastuzumab is believed to contribute to the efficacy of T-DM1 – not just due to efficient binding, but by exerting some immune-mediating effects. I’ll take it. Why get creative? We don’t need a more perfect antibody. The benefit is in the payload.
Synthon has been so quiet about their trastuzumab-duocarmycin (alkylating agent) ADC that I was surprised to find that it opened a P3 a year ago in HER2+ MBC, adorably called TULIP. They’re from the Netherlands. They had an ASCO abstract. Preliminary ORR of 33%, and no one died. Their eyes got a little runny. Cool. Sounds good.
Daiichi has been so busy with DS-8201a lately that they probably deserve a separate post (spoiler: am pumped for this drug), and we’ll skip over Ambrx, which no one knows anything about. That brings us to the ADCs that target, well, something. Maybe cancer.
Seattle Genetics is developing what used to be called SGN-LIV1a, which purportedly targets LIV-1. What’s intriguing about this is the evolution of the study design on their P1, which has been open since the Year of Our Lord 2013. It’s progressed from a dose escalation in 50 subjects where positive LIV-1 expression on a new biopsy was required for enrollment to a 300-subject, multi-cohort free-for-all where a new biopsy is required for enrollment. The new biopsy thing kills me; where do sponsors get the audacity to require this? Despite making it a condition of enrollment, they don’t have to pay for it, as it can easily be billed as routine care. More importantly, it’s risky for many patients. Especially considering the risk/reward on P1s: if I can die from unexplored toxicity, you don’t get an invasive fresh biopsy. At any rate, SeaGen has now changed course to say that LIV-1 is expressed almost universally in metastatic breast cancer and reported some early results (25% ORR in a TNBC cohort of 60 subjects). I’m not sure the early responses will stand given Celldex, which also had an MMAE payload; whether the LIV-1 target is viable or not, these patients will have progressed on at least one tubulin binder and likely a couple. Let’s keep expectations low on this one, though they did beat IMMU on opening a first-line TNBC ADC + checkpoint inhibitor study (SGN-LIV1a + pembro) and got into the MORPHEUS study, so they’re definitely part of the conversation.
Immunomedics continues to be irritating. They are relentless in their promotion of their TNBC unicorn that has an SN-38 payload that’s – what is it? – four billion times as potent as irinotecan? Does that mean the patients will survive four billion times as long? IMMU has years of follow-up on these subjects by now, but we’ve only been fed the same tiny nibbles of data over and over; as a reminder, it was a 30% response rate on a cohort of MGH dream patients. This won’t hold up in phase 3, but IMMU got FDA to accept their BLA on Glitter Unicorn-umab on P1/2 data, with a PDUFA date set for January. It’s hard to call whether they’ll get approved or be forced to wait for the P3, but if they do get approved, here’s hoping they go away for a while. With weak data, IMMU should be pretty well trapped in the third-line setting, and we can let more interesting agents (and study designs) sort out earlier lines of TNBC treatment.
With all this activity and so many viable drug candidates, I’m wondering if investors aren’t being more forgiving of Mersana in part because we don’t really need them. We have some near-term approvals coming that will significantly increase the number of ADCs on the market, but the big change since T-DM1 in 2013 is that we’re now fully committed to combination therapy. Targeted drugs with manageable toxicity profiles are making creative cocktails possible, and the results are a lot more compelling than what we’re seeing in the box-checking monotherapy trials that get these agents approved. For instance, T-DM1 performs well on its own, but we’ve already been teased with a 60% response rate when you pair the drug with neratinib. It’s never been easy to enroll a phase 1, but when the sky’s the limit on combos where there’s already some comfort and clinical experience, the competition for patients and investigators is going to intensify.
I didn’t think neratinib was getting through. As much as I want more flexibility in prescribing and a more moderate drug approval pathway, why does it have to be neratinib?
Despite very modest clinical benefit, a lot of toxicity and a broad label, this morning’s FDA panel voted 12-4 in favor of more options for cancer patients. The panelists did seem to take patient selection seriously, though it’s unclear how that will pan out when Puma is loose in the market. What I’m curious about is whether patients will demand it, whether the patient representatives Puma paid to speak – the what-if-Mommy-dies, I-want-to-do-everything-to-fight-this types – are representative of the overall population. Continue reading “The Puma Panel”
Puma presented at Cowen today, and I listened to the webcast hoping for a reaction to APHINITY, but alas, they kept Q&A to the breakout session. The tone of the presentation did seem a little grim, but between the crushing of adjuvant dreams and half the slides being devoted to unmanageable diarrhea, I guess it was always going to play grim. Continue reading “Puma Post-APHINITY”
Which is all we know right now, with actual numbers to come later in 2017 (ASCO?), but this morning Roche announced that APHINITY met its primary endpoint of significant improvement in disease-free survival in patients treated with Herceptin, Perjeta and docetaxel in the adjuvant setting.
I can’t wait to see the numbers, but it almost doesn’t matter: Herceptin going off-patent is no longer an issue, and Roche has secured its ownership of the HER2+ patient from date of diagnosis until, well, forever. I’ll be interested to see if Perjeta becomes a co-backbone of HER2+ treatment alongside Herceptin, in the sense that you never really stop Herceptin, regardless of how many times the patient progresses on it; we tend not to even do a lot of biopsies to confirm that HER2 status hasn’t reversed, despite the fact that a flip from HER+ to HER2- does happen in the recurrent and metastatic settings. It’s too soon to consider whether Perjeta will still be the first-line HER2 treatment of choice in recurrent or metastatic disease if the patient has been previously treated with Perjeta, but assessing durability of benefit through multiple courses of treatment is one of the many possible next steps for this agent.
Galena continues to hobble along with NeuVax, resisting defeat even though their peptide vaccine targeting HER2-positive breast cancer has failed in patients who have HER2-positive breast cancer as well as in patients who have breast cancer that is, ahem, HER2-lite (this is not a thing). With each failed study, Galena becomes less ambitious: the company announced the presentation of a study-update abstract at San Antonio where the study in question features neither real cancer nor real endpoints.
Neratinib is basically useless and has unmanageable side effects. Puma can publicly acknowledge only one of these problems, so here we are, with the company testing various diarrhea prophylaxis strategies to support an argument that a 2% increase in five-year disease-free survival among early-stage HER2+ breast cancer patients is somehow worth all this misery. Continue reading “New strategies for SEs, but same old neratinib”
B4 U Consent 