bladerunner1717
2 years ago
MRSN initiated at Citi with a $12 price target.
With Upcoming Ovarian Cancer Data, Analyst Sees 100% Upside For Mersana Therapeutics
Vandana Singh
Fri, January 20, 2023 at 12:16 PM PST
In this article:
MRSN
+9.97%
Citi initiated coverage on Mersana Therapeutics Inc (NASDAQ: MRSN) with a Buy rating and a price target of $12.
The analyst says the topline registrational data (expected in mid-2023) from the UPLIFT Ph2 study evaluating upifitamab rilsodotin (UpRi; NaPi2b ADC) in platinum-resistant ovarian cancer (PROC) will be a catalyst of significant debate.
Citi analyst says that while readout will be binary, investors are underappreciating UPLIFTβs probability of success in NaPi2b-high patients, given the promising efficacy observed in Phase 1.
If the UPLIFT study results are positive, it will lead to a clear pathway to an accelerated approval filing by YE23.
The analyst writes that UpRiβs durability in Phase 1 was in-line or better than single-agent chemo SOC and the recently approved ADC Elahere.
On toxicity, reduced dosing and patient selection strategies should mitigate the risk of Gr4/5 pneumonitis seen earlier in Phase 1.
In December, Mersana announced its third significant collaboration agreement in 2022, reflecting its increasing role as an ADC partner.
The company announced a research collaboration and commercial license agreement with a subsidiary of Merck KGaA (OTC: MKKGY) to discover novel Immunosynthen ADCs directed against up to two targets.
Mersana received an upfront payment of $30 million and is eligible to receive reimbursement of certain costs, up to $800 million in potential milestone payments.
Price Action: MRSN shares are up 10.48% at $6.43 on the last check Friday. (Up more in AH.)
Bladerunner
bladerunner1717
2 years ago
MRSN initiated at Citi with a $12 price target.
With Upcoming Ovarian Cancer Data, Analyst Sees 100% Upside For Mersana Therapeutics
Vandana Singh
Fri, January 20, 2023 at 12:16 PM PST
In this article:
MRSN
+9.97%
Citi initiated coverage on Mersana Therapeutics Inc (NASDAQ: MRSN) with a Buy rating and a price target of $12.
The analyst says the topline registrational data (expected in mid-2023) from the UPLIFT Ph2 study evaluating upifitamab rilsodotin (UpRi; NaPi2b ADC) in platinum-resistant ovarian cancer (PROC) will be a catalyst of significant debate.
Citi analyst says that while readout will be binary, investors are underappreciating UPLIFTβs probability of success in NaPi2b-high patients, given the promising efficacy observed in Phase 1.
If the UPLIFT study results are positive, it will lead to a clear pathway to an accelerated approval filing by YE23.
The analyst writes that UpRiβs durability in Phase 1 was in-line or better than single-agent chemo SOC and the recently approved ADC Elahere.
On toxicity, reduced dosing and patient selection strategies should mitigate the risk of Gr4/5 pneumonitis seen earlier in Phase 1.
In December, Mersana announced its third significant collaboration agreement in 2022, reflecting its increasing role as an ADC partner.
The company announced a research collaboration and commercial license agreement with a subsidiary of Merck KGaA (OTC: MKKGY) to discover novel Immunosynthen ADCs directed against up to two targets.
Mersana received an upfront payment of $30 million and is eligible to receive reimbursement of certain costs, up to $800 million in potential milestone payments.
Price Action: MRSN shares are up 10.48% at $6.43 on the last check Friday. (Up more in AH.)
Bladerunner
jaybe
6 years ago
Abstract out for WCLC.....
P2.09-24 - MERS67 is a Novel anti-NaPi2b Antibody and Demonstrates Differential Expression Patterns in Lung Cancer Histologic Subtypes
16:45 - 18:00 | Presenting Author(s): Rebecca Mosher | Author(s): Hui Yu, Kim Ellison, Pamela Shaw, Rafal Dziadziuszko, Eric Hailman, Christopher J. Rivard, Fred R. Hirsch
Abstract
Background
NaPi2b is a sodium-dependent phosphate transporter expressed in lung, ovarian, and thyroid cancers. Prior studies have suggested an enrichment of expression in lung adenocarcinoma (ACA).
XMT-1536 is a NaPi2b targeting ADC (Antibody Drug Conjugate) comprised of a humanized antibody (XMT-1535) conjugated with 10-15 auristatin F-HPA (AF-HPA) payload molecules via the Dolaflexin platform. AF-HPA is capable of controlled bystander-effect killing, resulting in efficacy in models with heterogeneous antigen expression, and is metabolized intra-tumorally to an active non-permeable metabolite to enable greater systemic tolerability. Previously, we demonstrated pre-clinical activity of XMT-1536 in human primary xenograft models of non-small cell lung cancer (NSCLC).
MERS67 is a human-rabbit chimeric antibody derived from XMT-1535. MERS67 has been formatted for use as an immunohistochemical reagent by multiple methods and expression has been shown to correlate with response in an unselected series of primary ovarian cancer xenografts. (AACR-EORTC, 2017)
We evaluated MERS67 to see if it would preferentially stain lung adenocarcinoma (ACA), as has been demonstrated using other NaPi2b antibodies.
Method
An immunohistochemical assay for MERS67 was established on a Leica BondRx Instrument. The assay was performed on tissue microarrays (TMA), including NSCLC and small cell lung cancer (SCLC) cell line arrays, and a NSCLC human tumor array. Tumors in the NSCLC array had previously been classified based on morphologic features only. All arrays were scored based on the H-score method.
To characterize the primary tumors further, the tumor TMA was stained with TTF-1 and p40, markers of ACA and squamous cell carcinoma (SqCC), respectively. Results of this staining were compared to MERS67 staining patterns.
Result
H-Scores in the NSCLC cell line TMA ranged from 0-260, and from 0-100 in the SCLC TMA. Within the tissue microarray, 99 individual cases were evaluable. By morphologic classification 63 cases were SqCC, and 23 cases were ACA. Using an arbitrary cut point of H=50, there was a statistically significant difference in the number of NaPi2b positive ACA cases (19/23) vs SqCC (3/63). Among 43 cases where p40 and TTF-1 were evaluable and were in agreement with morphologic diagnosis, 7/7 cases of ACA were positive for NaPi2b, while 0/36 SqCC were positive.
Conclusion
MERS67 is an anti-NaPi2b antibody that frequently demonstrates immunoreactivity in lung ACA. MERS67 is a chimeric antibody related to XMT-1536, a proprietary anti-NaPi2b ADC. Target expression using MERS67 is being evaluated in an ongoing XMT-1536 Phase 1 clinical trial enrolling non-squamous NSCLC patients.
jaybe
6 years ago
I would add here if I hadn't loaded up on ADXS last week.
I trust Ana to handle this carefully and professionally and to resolve the hold in less than a month. I assume they are already on dose level 9, since ASCO data cut in May nearly completed DL7 and its a 4-week cycle to assess DLT prior to moving to next dose. Dose level 7 patients have been on drug for three months, with one DLT and one Grade 3 event, AST elevation (reported at ASCO). So far about ~50 patients have been dosed with this payload, including 1522 & 1536, and this is the first Grade 4 or 5 event. All patients are very sick, with average of 4 prior regimens.
Definitely a risk-raising event, but given the established MOA and safety reported to date, I think this will turn out to be a monitorable and manageable event for investigators. Of course this is not good news, but likely outcome will force early reporting of additional safety data around time of Q2 call, pencilled for August 10th.
jaybe
6 years ago
Mersana...after ASCO...
Looks like a long summer for Mersana. The ASCO data was a real cliff-hanger, responses trending in the right direction, but AEs showing up to, so woefully inconclusive. Doses 8-10 will take ~6-8 weeks each so any meaningful update will be at ENA'18 in mid-November, which is also likely the venue for unveiling the 3rd candidate. Patent app for 3rd drug should publish by end of summer.
In other news, DS-8201 continues to crush the competition and raise the bar for XMT-1522. ASCO data showed 50% ORR for Her-2 low MBC patients. Mersana will need to approach this number with some differentiation in order to compete.
Hopefully XMT-1536 will also reach MTD this year, but readout would be AACR in April at earliest.
jaybe
6 years ago
Potential competitor MEDI4276 flames out...
The wait is over for long overdue clinical data on AZD's "next-gen" Her-2 ADC MEDI4276. Published Phase 1 results this week at TAT demonstrated an ORR of 5% with DLTs and MTD at higher doses. This result most likely signals the end for this candidate as competitors such as DS-8201 already show ORR's over 50% in a similar population (3L), with 31% ORR for Her2-low.
XMT-1522 will need to clear 50% Her2+ and 30% Her2-low hurdles, with differentiating benefits, to be competitive. In the near term only DS-8201, SYD985, and PF-06804103 are "best-in-class" ADC competitors to keep an eye on.
https://academic.oup.com/annonc/article/29/suppl_3/mdy048.005/4917517?searchresult=1
jaybe
7 years ago
Article in ADC Review notes Mersana's progress...
Pretty much a recap of JPM updates, potentially five abstracts at AACR in April:
1. Phase 1 data for XMT-1522, safety, efficacy, and RDP2.
2. Pre-clinical on XMT-1536 in IO combo.
3. Pre-clinical on next ADC, IND in 2018.
4. Pre-clinical on Takeda-ADC, IND in mid-2018.
5. Pre-clinical on new platform - new linker and PBD payload.
Likely at least 3 of the above, importantly #1 sets the table for all others. Abstracts posted online March 14.
https://adcreview.com/news/expanding-field-antibody-drug-conjugates/