The Largest Biotech IPO on Record and a New HIV Treatment Option – This Week in Biotech #97
Merck's Idvynso offers the first integrase-free HIV switch option, Replimune cuts 60% of staff after a second FDA rejection, and Kailera's $625M debut signals where obesity investment is headed next.
Welcome back to This Week in Biotech by Biotech Blueprint, edition 97, covering biotech and biopharma news from April 17th to 23rd, 2026.
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VIDEO SUMMARY
THIS WEEK’S KEY TAKEAWAYS 🔑
Merck’s Idvynso got FDA approval on April 21, a few days ahead of its scheduled review date, for virologically suppressed adults with HIV-1 looking to switch regimens. The significance isn’t the timing but what the drug represents, because for the first time, a suppressed patient can move to a two drug regimen that contains neither an integrase inhibitor nor tenofovir. Both drug classes are effective but carry long term baggage. Integrase inhibitors with weight gain and resistance accumulation risk, and tenofovir with renal and bone signals in susceptible patients. Idvynso won’t displace Biktarvy overnight, but it establishes a non-integrase standard of care in the switch setting that didn’t exist before.
Replimune had the opposite kind of week. The company received its second complete response letter for RP1 plus nivolumab in advanced melanoma, again on the same grounds: the trial couldn’t isolate what RP1 was actually contributing on top of a checkpoint inhibitor that already works well on its own. Replimune then announced layoffs of more than 200 people, roughly 60% of its workforce.
Kailera Therapeutics raised $625 million in its Nasdaq IPO, the largest biotech debut on record, for a Phase 2 obesity drug licensed from China’s Hengrui Pharma. That number says something about where investors sit right now. Lilly and Novo define the current GLP-1 battlefield, but the race for next gen differentiated mechanisms is still wide open, and the market is clearly willing to fund it at scale.
Beeline Medicines launched with $300 million in Series A funding built on five programs licensed from Bristol Myers Squibb, led by afimetoran, an oral TLR7/8 inhibitor in Phase 1b/2 for lupus with FDA Fast Track Designation. Same logic as J&J’s divestiture of bota-vec to MeiraGTx last week. These aren’t unwanted assets. Large companies are just concluding that focused independent teams run early precision immunology programs better than internal commercial machinery does.
AACR wrapped up April 22 in San Diego with Revolution Medicines presenting updated first-line daraxonrasib data alongside the already confirmed Phase 3 overall survival results. ASCO abstract titles dropped April 21, full data embargoed until May 29 through June 2 in Chicago, with the daraxonrasib Phase 3 RASolute 302 dataset confirmed for a plenary oral on May 31. The next six weeks will be the most data dense stretch of the year for precision oncology, and Revolution’s ASCO presentation is the one everyone is watching.
BIOTECH/PHARMA NEWS 🧬
🔹 The FDA approved Idvynso on April 21 for virologically suppressed adults with HIV-1 looking to switch off their current regimen. The once-daily single tablet pairs doravirine, a non-nucleoside reverse transcriptase inhibitor, with islatravir, which works through a distinct mechanism from conventional HIV drugs. Two Phase 3 trials supported the approval: a head-to-head against Gilead's Biktarvy showed identical efficacy at Week 48, and a switch trial showed 96% of Idvynso recipients maintained viral suppression. The clinical argument is straightforward: long-term exposure to the drug class in Biktarvy carries associations with weight gain and metabolic effects, and tenofovir carries renal and bone signals in some patients. Idvynso removes both in a single pill. Commercial availability begins May 11, and the switch population is large. The real launch question is formulary access.
🔹 Replimune received a second complete response letter for RP1 in combination with nivolumab for advanced melanoma, and the FDA's concern hasn't changed: a single-arm trial can't isolate what the drug is actually contributing on top of nivolumab alone. The company followed the news with layoffs of more than 200 employees, roughly 60% of its workforce. The broader lesson for the oncolytic virus field is hard to ignore: compelling early signal in open-label studies does not survive FDA scrutiny if the registration design can't answer the additive benefit question. Any future combination program will need a randomized arm comparing the backbone therapy alone. That's the bar now.
🔹 Kailera Therapeutics raised $625M in its Nasdaq IPO, the largest biotech debut on record, surpassing Moderna's 2018 raise. The company's lead program is oral ribupatide, a GLP-1/GIP dual agonist currently in Phase 2 for obesity, licensed from China's Hengrui Pharma. That China angle matters: Hengrui has one of the more productive GLP-1 pipelines outside the US, and Kailera is essentially a vehicle to bring that chemistry into the American development and regulatory system. The size of the raise signals that investors aren't waiting for the Lilly versus Novo battle to resolve before backing the next wave of obesity drugs.
🔹 Beeline Medicines launched April 15 with $300M in Series A financing, built around five programs licensed from Bristol Myers Squibb targeting immune-mediated diseases. The lead asset is afimetoran, an oral TLR7/8 inhibitor in Phase 1b/2 for lupus with FDA Fast Track Designation, with a Phase 2 readout expected in the second half of 2026. The pipeline also includes a TYK2 inhibitor and an IL-2/CD25 fusion protein. The structure mirrors what we've seen elsewhere recently: a large pharma deciding a set of early-stage programs is better run in a leaner, focused vehicle than inside a commercial organization. BMS keeps some economics, Beeline gets the operational flexibility. Whether afimetoran can compete in lupus against established options like belimumab and anifrolumab depends on tolerability, and the Phase 2 data will be the first real read on that.
🔹 The FDA approved Sanofi/Regeneron’s Dupixent (dupilumab) for chronic spontaneous urticaria, a condition causing persistent unpredictable hives, in children aged 2 to 11 who don't respond adequately to antihistamines. This is Dupixent's ninth allergy-related indication. The approval was supported by Phase 3 data from the LIBERTY-CUPID program in adolescents and adults plus pharmacokinetic and safety data in the target pediatric age group. No single pediatric label expansion moves the needle much on a drug already doing over $16B a year, but Sanofi and Regeneron have been methodical about this: build formulary positioning across the entire atopic disease spectrum, one indication at a time.
CLINICAL TRIAL UPDATES 📊
🔹 Doravirine / Islatravir (Merck) - Phase 3, HIV-1. The two trials behind the Idvynso approval are covered above. The clinical read is clean and the non-inferiority bar against Biktarvy is met. The standard for any competitive HIV switch study is now a head to head against an approved non-integrase inhibitor regimen at Week 48, and Merck cleared it.
🔹 Daraxonrasib (Revolution Medicines) - Phase 1/2, first-line metastatic pancreatic cancer. Revolution presented early first-line data at AACR this week, though full efficacy numbers remain embargoed until the slides are released. What’s notable is that Revolution has submitted for a plenary presentation at ASCO for the Phase 3 dataset, which signals internal confidence in the full data package. The scientific question worth watching is whether the drug’s multi-variant RAS targeting works as well in first-line patients, whose tumors haven’t yet been shaped by chemotherapy selection pressure, as it does in the second-line setting where the landmark results came from. Still early, still small cohorts, but the first-line ambition is clearly alive.
WATCHLIST 👀
ASCO 2026 abstracts: Full abstracts release May 21; meeting runs May 29 to June 2 in Chicago
Daraxonrasib (Revolution Medicines): Phase 3 RASolute 302 plenary presentation, Abstract LBA5, May 31, ASCO 2026
Darovasertib + crizotinib (IDEAYA): Phase 2/3 OptimUM-02 late-breaking oral presentation, ASCO 2026; NDA submission targeted H2 2026
Viridian elegrobart: REVEAL-2 readout (chronic thyroid eye disease) expected Q2 2026; BLA targeted Q1 2027
Lilly Foundayo T2D NDA: Filing targeted end of Q2 2026; ACHIEVE-4 MACE HR 0.84 and all-cause mortality HR 0.43 (not multiplicity-controlled) are the supporting data
Beeline afimetoran (SLE): Phase 2 completion targeted H2 2026; pivotal decision to follow
Novartis pelacarsen (Lp(a)HORIZON): Lp(a) lowering cardiovascular outcomes trial; timing on readout not confirmed but widely described as a high-stakes event for 2026; watch for announcement
IDVYNSO commercial launch: Available in pharmacies after May 11; payer formulary positioning and switch uptake versus Biktarvy will be early launch metrics to watch
Have a great rest of your week and thanks for reading Biotech Blueprint!
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