In P3 this time. So are we done here? This outcome would be much more satisfying if it weren’t so freaking obvious.Continue reading “Entinostat Fails. Again.”
Joining DS-8201 as a likely FDA approval in early 2020 is tucatinib, a HER2-targeted small molecule TKI that I’ve been fangirling for years. If this keeps up, I’m going to be able to treat my cancer with actual new medicine and not just mental fortitude.
Not to malign the Herceptin-plus-X paradigm that’s bridged me all this time, but it’s been a while since the T-DM1 and Perjeta launches of 2013. In metastatic cancer years, it’s a real long while.
Onto the successes of HER2CLIMB, Cascadian Therapeutics’ (now Seattle Genetics’) phase III trial comparing tucatinib + Herceptin + Xeloda to placebo + Herceptin + Xeloda. The trial enrolled 612 subjects and was randomized 2:1, and subjects had been previously treated with Herceptin, Perjeta and T-DM1. The press release notes that 47% of subjects had brain mets at the time of enrollment. A classic placebo-controlled RCT in a tough crowd? Yes, please. What’s not to like about these guys?
We don’t know a lot yet, with actual numbers to be presented at San Antonio. But to pull the highlights from the press release:
- Tucatinib + H/Xeloda combo met its primary PFS endpoint, with a 46% reduction in risk of PD or death compared to placebo + H/Xeloda
- Among secondary endpoints, OS was superior for the tucatinib arm versus placebo + H/Xeloda, with a 34% reduction in risk of death
- For patients with brain mets at baseline, tucatinib + H/Xeloda offered a 52 percent reduction in the risk of PD or death compared to placebo + H/Xeloda
Not a bad teaser, right? Congrats, Cascadian.
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.
Syndax announced on Thursday that they missed PFS in their P3 E2112 study comparing entinostat + exemestane (Aromasin) to placebo + exemestane in advanced HR+ breast cancer, which resulted in a top-notch corporate quote:
“While the PFS analysis did not show a statistically significant benefit, E2112 was primarily designed to determine whether the combination of entinostat and exemestane could improve OS based on the compelling OS results obtained in the Phase 2b ENCORE 301 trial …”
They didn’t even WANT to hit PFS, okay?
Never mind that there are two primary endpoints in E2112, meaning it’s an and/or situation and the study was not, in fact, primarily designed to assess OS.
ENCORE 301, the basis on which Syndax received their Breakthrough Therapy designation, is reported here. That study (N=130, randomized 1:1 to entinostat + exemestane or placebo + exemestane) met its primary endpoint, with PFS of 4.3 months in the entinostat arm and 2.3 months in the control arm. OS was an exploratory endpoint, with entinostat associated with median OS of 28.1 months, compared to 19.8 months in the control arm. The enrollment criteria are similar between ENCORE 301 and E2112, except premenopausal patients and prior fulvestrant are both allowed in E2112, and E2112 appears to have a cohort with non-measurable disease.
It would be unusual for the benefit of an anti-cancer therapy to be better reflected in OS than PFS; this might happen with PD-1/PD-L1s, but that may not be universally agreed, and it’s not likely to be the case for entinostat. Syndax are trying to recast entinostat as an immunotherapy with their checkpoint inhibitor collaborations (oh look, it’s a 10% response rate with pembro), but when I tried the drug a couple years ago, it was just an HDAC inhibitor. And it sucked.
I was on entinostat for three cycles and got dose reduced after the first and again after the second, which remain my only dose reductions in eight years of nonstop treatment. I was off study for progression at the end of the third cycle, once I’d used up my two protocol-permitted dose reductions without improvement in my labs. Weird how that happened, right?
Whatever: I was happy to be kicked off, because I have never felt more like dying in my life as on that drug. It was miserable. I felt sick and tired all the time, it wiped out my white cells, red cells and platelets, and my bones felt hollow. It sounds ridiculous, and this was never attributed to the study drug, but they were not like that before. They were totally normal bones before.
The feeling resolved after I went off study, but not before I broke my hand in a freak incident involving a leash that … brushed across my hand very fast. You would think this sort of thing would not cause a spectacular extremity fracture (the surgeon who wired it together later presented it at a conference!), and it could have been a coincidence, but I blame the entinostat.
The lack of efficacy is the focus here (with a pointed reminder that not all drugs anointed Breakthroughs pan out), and a P3-grade PFS fail rightly overshadows toxicity and my unconfirmed Bird Bones anecdote. I just like the story, lest there be any suspicion that entinostat has “well-tolerated” going for it. In a true stretch of corporate credibility, we’re being forced to wait for E2112 to fail definitively, because Syndax were clear they would keep performing scheduled OS analyses until everyone was dead. Or, you know, they see an OS benefit. Whichever comes first.
ESMO was a snooze, right? No new drugs out of nowhere, no hotly-anticipated studies knocking it out of the park (cough, IMpassion, cough). Which I guess frees us up to talk about alpelisib.
Novartis announced results from their SOLAR-1 study, which succeeded where buparlisib (also NVS) and taselisib (Roche) failed. In patients with PI3K-mutated, hormone-positive and HER2-negative advanced breast cancer, alpelisib plus fulvestrant achieved a PFS of 11 months, compared to 5.7 months for fulvestrant alone, and an ORR of 36% for alpelisib + fulvestrant, which compares to 16% in fulvestrant alone. These are hormone-positive patients, so we won’t have OS data for another few decades, but these are good numbers. It wasn’t Ibrance/letrozole, which blew out a wild PFS in the first-line setting (notably, the SOLAR-1 patients will have progressed on an AI as well as possibly a CDK 4/6 inhibitor), but it’s good, and the first real validation we’ve seen of PI3K targeting in breast.
This would have been a perfect announcement if not for the AEs. Hyperglycemia was reported for 64% of alpelisib patients (compared to 10% among controls); in 37%, hyperglycemia was grade 3/4. Grade 3 hyperglycemia is defined as blood sugar of 250-500 mg/dL; grade 4 is >500 mg/dL. Which sounds challenging, even in patients who theoretically have bigger problems. These are patients that are poised to live a really long time with a good quality of life. Is any onc out in the community, dealing with real patients, psyched about managing blood sugar of 400? The press release didn’t break out the rate of dose reductions, but what does that inevitability do to efficacy?
To their credit, Novartis has been fairly relaxed about enrolling diabetics in its PI3K studies. SOLAR-1 excluded type 1, but allowed controlled type 2; BELLE-2 and BELLE-3, the buparlisib studies in HR+ MBC, didn’t appear to restrict based on diabetes or blood glucose, though other, investigator-led studies did. SANDPIPER, the P3 taselisib, excluded Type 1 or Type 2 diabetes requiring anti-hyperglycemic medications. Still, not everyone is going to be represented in the SOLAR-1 population, and there’s a reasonable likelihood that physicians will be prescribing for patients with high baseline blood glucose or less well-controlled diabetes. (And while there’s an argument that metformin and PI3K/AKT/mTOR inhibitors are synergistic, and that by adding metformin to one of these drugs you’d get both protection against a blood sugar crisis and enhanced anti-cancer efficacy, there’s at least some evidence with everolimus that it’s not so straightforward. Though these diabetic neuroendocrine patients who were on metformin when starting evero did better than their non-diabetic counterparts.)
Everolimus is an older, HR+ breast-approved mTOR inhibitor that popped up in a couple of ESMO abstracts (here and here) that aren’t really interesting enough to discuss on their own but that roughly echoed what we know from BOLERO-2, which is that evero doesn’t really care about PI3K positivity. This is notable since this drug for patients with targetable, frequently-mutated PI3K has been one of the prime examples of precision medicine in practice. It’s been offered to me a couple of times based on genomic sequencing (never in a large center, obvs), which I always declined because I was waiting for one of the next-gen PI3Ks. Taselisib turned out to be a disaster, despite the all the strategizing that preceded signing that consent. I think this is a good example of the kind of hold that sequencing has over patients; those mutations feel a lot like capital, and I put a huge amount of effort into deciding when and how to cash it in. Diabetes aside, if alpelisib works, and exclusively in PI3K-mutated patients (there is PI3K-wild-type cohort in SOLAR-1 being tracked for a secondary endpoint), it could help reverse what has felt like a big disappointment in personalized medicine.
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.
|Sacituzumab govitecan (IMMU-132)||Immunomedics||TROP2*||SN-38 (irinotecan metabolite)||Phase 3|
|Trastuzumab deruxtecan (DS-8201a)||Daiichi Sankyo||HER2||Exatecan derivative||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.
A couple of weeks ago, Genentech announced that interim data were forthcoming (ESMO? SABCS seems a long way off) from IMpassion130, their P3, 900-subject, 1:1 randomized atezo + Abraxane v. placebo + Abraxane study in first-line, triple-negative metastatic breast cancer. To tide us over, they offered up a teaser: the study met its co-primary PFS endpoint in the intent-to-treat and PD-L1+ populations, and the company reported a positive trend in OS in the PD-L1+ population. The language was not subtle. In addition to touting 130 as the “first positive Phase III immunotherapy study in triple negative breast cancer,” Genentech said they were going to “submit to authorities globally with the aim of bringing this combination to people with triple negative breast cancer as soon as possible.”
What kind of data might be backing this up? Merck were slow to combine pembro and chemotherapy, so we don’t have a lot of context for what successful immunotherapy looks like in metastatic TNBC. But let’s mine abstract libraries past for details anyway. Continue reading “Handicapping IMpassion130”
Physicians disclose their industry payments to one another, in meeting slides and at the very ends of papers, and that’s about as much transparency as exists in clinical trial operations. Many patients don’t know their doctor is often paid by the head for enrolling study subjects. While I think that doctors should disclose their financial relationships to patients, I also think the same standard should apply to any entity with patient contact.
Odonate Therapeutics is the latest company with rights to the oral taxane tesetaxel; the Daiichi drug was previously licensed to Genta, which of course went bankrupt in 2012. There are two publications on Pubmed showing the drug’s lack of efficacy in humans, specifically a phase I/II non-small cell study that reported a response rate of 5.6% and an all-solid-tumors study that reported a best overall response of stable disease in 82% of subjects when the drug was combined with capecitabine. Those papers were published in 2008 and 2011, respectively, and, combined with a graveyard of studies of unknown ClinicalTrials.gov status in melanoma, bladder cancer and gastric cancer, you’d think tesetaxel was finished.
Odonate sat on the drug for four years before going public in 2017 and announcing plans to conduct a 600-subject phase III trial in hormone-positive metastatic breast, CONTESSA. For ASCO this year, they helpfully stripped out their target CONTESSA population from data reported at ASCO 2012. That trial, which Genta sponsored, was called TOB203. The latest poster seems to exist entirely to promote CONTESSA, given that the only difference between them is that the 2018 poster is purple and the 2012 poster is blue. (Linked to the full-size posters because the pics are coming out small; and yeah, I’m sure that response rate in their previously-untreated, cherry-picked subgroup is going to hold in a phase III RCT.)
But ASCO isn’t Odonate’s only creative effort at marketing their trial. Because is it really over until you’ve preyed on the patients themselves? The first press release on the new Odonate website is dated October of 2017, where the company announced their financial support for the Susan G. Komen foundation. In case you were wondering, $1.5 million at Komen buys you a purple banner proclaiming you a “partner” at the bottom of the screencap for your emotionally-manipulative video.
This video is featured prominently at www.CONTESSAstudy.com, and given that Komen has previously licensed their pink ribbon to a bucket of fried chicken, this is not the most egregious offense. It gets worse. And no, I don’t think this is all on Odonate.
On June 1, this headline popped up at BreastCancer.org’s metastatic breast cancer forums, which are the most popular breast cancer forums online. There are over 20,000 posts, and this one is right at the top.
Per the site moderators:
Why, yes, that is an exclamation point. There are 650+ trials recruiting or about to open in metastatic breast cancer listed on ClinicalTrials.gov, and funnily enough, this is the only one that gets an exclamation point on the cancer boards. And what exactly are we so excited about?
Oh hell no. I replied to the post stating basically exactly that. I mean, this entire blog pretty much exists because oncologists are corrupt, but let’s just baseline here: if you talked up a trial like this to a patient, you’d lose your license. This is beyond irresponsible. It is effectively an endorsement of a clinical trial. (I found one other trial announcement on the board, for the NCI-funded E2112, and you can compare the treatment when you don’t pay up.) And check out the URL in the post: “Featured” Trial. It’s featured. Because they gave us money, but we’re not going to disclose that anywhere. CONTESSA is, at present, the only trial listed on the page linked in the post. BreastCancer.org are under no professional obligation to accurately represent the drug, and the obvious defense is that they don’t have the expertise to evaluate the available data, but isn’t that the point? You can’t buy that kind of promotion at a doctor’s office. You can only get it here.
And an exclamation point is certainly in order when discussing an investigational drug. That f*cking exclamation point.
Let me emphasize: I can’t fault Odonate for their “partnerships”. I kind of respect the imagination. They have one sad product that has been plagued by failed trials, a past clinical hold and several changes of ownership; since they have made the baffling choice to keep this thing alive (…why?), they’ve got no choice but to enroll a trial. So while tesetaxel may be doomed and reflect an embarrassing misunderstanding of the direction of oncology, the idea to fund patient groups in exchange for trial promotion may be the best idea anyone at Odonate has ever had. Not that it’s a high bar, but patients are scarce, this drug has disappointed, any onc has better business prospects and if a patient’s peers and advocates endorse it, well, that might be the only chance it has to enroll. I believe it’s absolutely morally wrong to waste patients on shit drugs, but the onus is on the entity that accepts the cash to behave ethically. You can always decline the money. Easy e-mail – We act in the best interests of the patients we represent.
But that e-mail didn’t go out, and the check cleared, so there you go. These people are bound to nothing; not honor, not patient outcomes, and they preach to metastatic patients with OS on the line. We demand our beauty bloggers disclose when they receive a free lipstick to review, but the moderators on cancer forums, who have the power to keep a post at the top of the very first page and influence decisions that are literally life and death, are not held to any standard?
This story has been kicking around for a month, because I wanted to give BreastCancer.org a chance to make it right. And to their credit, they made an effort. They changed the title of their trials page from “Featured Clinical Trials” to “Sponsored Clinical Trials.” (That f*cking exclamation point is still in the header of the forum post.) Whether my comment triggered it or not, and I hope I’m not the only person who objected, I’m happy about the change. I commented on the thread again to applaud them for their transparency, making sure to reference the old language, lest anyone who visits the page in the future forget that there was a time when BreastCancer.org thought they would get away with using “featured” as code for “paid advertising”. Give patients some credit. I suspect most of us understand that industry relationships are an essential part of drug development and don’t care – as long as people are honest about it. I don’t believe drug companies are out to get us, and my distrust is generally with the physician-middlemen who pretend (to patients, not their peers) industry doesn’t exist and doesn’t influence care. Of course it does. Let’s admit it and go forward, in service of true openness and collaboration.
Update: the morning after I posted, investigators presented SANDPIPER data in an MBC session. In response to modest benefit and AE concerns, Roche announced that they would not be pursuing an FDA submission.
Spoiler alert: check out this table presented today at ASCO.
I enrolled in a study combining taselisib with HER2-targeted therapy (T-DM1 or HP, with prior therapy on either option allowed) in metastatic breast cancer. Worth noting: PI3K mutations were not required for enrollment, in line with Genentech’s overall all-comers strategy (e.g., non-targeted atezo). My experience was not apples-to-apples with the MATCH patients, who were enrolled solely on the basis of a PI3K mutation, regardless of tumor origin. But I think it’s analagous, given that I only enrolled because of my PI3K mutation. In 2012 I had a Caris test, which was then much more exciting than it is now; so exciting that I wasn’t even mad that they depleted a five-centimeter block of tumor doing a panel of about a dozen genes plus chemosensitivity testing. We’ve come a long way in six years. Among the results was a PI3K mutation. The wonderful Dr. Cristofanilli, whose enthusiasm for targeted therapies and novel diagnostics is truly inspiring (whether he’s entirely right about their clinical relevance, it’s contagious), told me five years ago to try Afinitor in combination with Herceptin and vinorelbine. Afinitor targets mTOR, which shares a pathway with PI3K and is approved for use in hormone-positive breast cancer, in combination with Aromasin, among other indications. He recommended it over a T-DM1 trial, because he predicted, accurately, that in the near future it would be no problem to get T-DM1, though at the time it seemed like the drug would never make it to market; payer uncertainty with the off-label Afinitor was another issue (BOLERO-3 was published a couple of years later, and I imagine this would make reimbursement less of a wildcard, assuming the prescriber was willing to push for it). While I was touched that after one appointment, he would’ve gone to bat with my insurer, I went with the T-DM1 trial. There were so many next-gen PI3K inhibitors in development, and I had my eye on BKM120.
I waited. And waited. Development was apparently discontinued sometime late last year. If you look at Novartis’ 2017 annual report, BKM120 is suddenly absent from the pipeline. This was not entirely surprising, to the extent that I didn’t even see it reported anywhere, given the AEs; PI3K inhibitors are known to cause neuro issues, and the poor ER+ study subjects with their indolent cancers were up and trying to kill themselves on trial. There were also efficacy concerns. BYL719 still has a heartbeat, but I haven’t heard much about it. They’re trying it with letrozole in HR+ breast, and it seems fine.
Anyway, this story is about taselisib. I enrolled, and I lasted one week. The nausea was terrible, terrible, ondansetron every eight hours terrible, which I usually avoid because I’m so scared that if I take it, I’ll build up some kind of anti-emetic tolerance and this drug that is considered magic and the best choice we have against nausea will no longer work for me. My usual strategy against nausea is to eat candied ginger (it’s stocked with all the nuts in Whole Foods) and to lie absolutely still, which is reasonably effective. Plus my skin progressed, after a few years of relative stability, and I panicked. It just went crazy.
ME: I feel like I did something mutagenic. That maybe the PI3K was there, but it wasn’t driving anything, and now I’ve woken it up.
DOCTOR: Yeah, that’s legitimate.
He’s the best because he tells me the truth.
Like 100% of the MATCHed patients referenced above, I was not a responder. There seems be some suspicion of the drug among physicians; my husband came home recently and said someone asked him, re: taselisib, “Does that thing even work?”
Well. We’ve associated the efficacy of drugs targeting the mTOR pathway with hormone-positive breast because that population is pretty overwhelmingly PI3K-mutated (it may be as high as 50%). But if you look at MATCH, the mutation doesn’t really explain it. For me personally, this also isn’t the first time I’ve targeted the mTOR pathway; I’ve taken metformin since diagnosis, and if that has any anti-cancer activity, it’s along this pathway, and I definitely haven’t associated it with rapid PD.
I haven’t written about my taselisib experience because I really don’t know what to make of it; it’s disappointing, and I don’t want this blog to be a series of lame anecdotes, because oncology is a thrill to me in ways that are separate from my own case. While I want to be honest about what happens to me, it’s a lens and not the thing itself. So when I see that I join the 0% of MATCH patients who were PI3K mutated and yet taselisib non-responders, there is some relief that I’m not going to be the one to be a black mark on this drug (I did ask my doctor if I would be on the record as non-evaluable, because I progressed halfway through the first cycle, or as a PD, and I don’t actually know what happened), but I also want us to believe in genomics until something better comes along. Maybe PI3K is just not an ALK, or, in ASCO 2018 terms, a RET. It’s not like chemo works so great. We can do better than that, right?
Three years ago, I learned of KD-019, an EGFR-inhibiting wonder TKI for which there just happened be a study enrolling, right at the mid-tier academic institution/portal to hell in which I was currently sitting. I nodded along appreciatively to phrases like better than Tykerb! while thinking, Kadmon. Kadmon. Oh, right, the one where the CEO just got out of prison.