Celldex's triple-negative breast cancer progress

Triple-negative breast cancer (TNBC) is a nasty form of the disease that does not respond to receptor-targeted therapeutics (Herceptin or Tamoxifen), as the receptors of interest (estrogen (ER), progesterone (PR), or HER-2) are not found in TNBC. The only marginally-effective treatments against TNBC are general chemotherapies, but overall response and survival rates are much lower in TNBC versus other breast cancers.

Celldex (CLDX) released P2B results from a clinical trial using their drug (CDX-011) in TNBC. Results suggest that the Celldex drug works against triple-negative cancers that overexpress a protein known as GPNMB. Celldex reports that 36% of patients with TNBC and high GPNMB expression responded to CDX-011, while zero patients in the equivalent control groups responded to standard chemotherapies. (N=11 and 3 respectively, so let's not overreact.)

(Also: NON-TNBC patients with high GPNMB expression showed a response to CDX-011. (32% response vs. 13%. N=25 and N=8, respectively.

Adding these two groups together yields a response in 15 of 36 patients (42%!) with high GPNMB expression treated with CDX-011, with 1 responder of 11 in the control group. (i.e. not treated with CDX-011.)

This data is encouraging for Phase 2B, and warrants a Phase 3 trial AND a large pharma partner, something I would expect to see Celldex close on by the end of 2012. (TNBC sometimes responds to EGFR treatment, so I'd expect Celldex's partner to be a company with an EGFR product interested in prescribing a combination of products. (Hello, AMGN, and Roche!)

(Speaking of combination, CDX-011 uses Seattle Genetics' antibody linked technology, whereby the antibody with affinity to GPNMB delivers a chemo payload to the cancerous cell. I need to take another look SGEN soon.)


CLDX Financial overview, as of 5/28/12:
Market cap: $264M (even after popping ~10% on the tnbc trial news
Cash on hand: $92M, burning ~$40M/yr.
Enterprise value: $172M
ex-CDX-011 enterprise value: $35M-$50M, as CLDX receives $9M/year in license income from successful outlicensing.
CDX-011 value (roughly): $130M ($172M less $42M in ex-CDX-011 enterprise value ($42M= midpoint of $35M-$50M valuation.)


What's the value of CDX-011?

CDX-011 Market math:
CLDX asserts that 35% of all breast cancer patients could benefit from CLDX-011, which suggests:

Annual US breast cancer cases: ~180,000
% of breast cancer that is TNBC: 15-25% via various sources. Let's say 20%.
US TNBC market: 36,000
GPNMB overexpressers as a %age of TNBC patients: 12% of TNBC, or 4,320

US GPNMB market:27,000
non-TNBC patients overexpressing GPNMB: 15% of all breast cancers
US market for GPNMB overexpressors (w/o TNBC): ~27,000 
Likely US GPNMB+ market: 31,320 annually, and therefore,
Total annual world market for CDX-011: between 80,000 and 120,000 patients worldwide.

Assuming $20k revenue/patient ($50k/patient revenue, but only 40% penetration at peak), CDX-011 would then peak at ~$2B/yr in revenue, and therefore peak product value of ~$12B (equivalent to Celgene's 6X sales valuation.)

Risk-adjustment of CDX-011 value: let's assume the following:
-that FDA approval is 2 years away,
-peak revenue is 4 years post-approval
-25% discount rate
-CDX-011 has a 40% chance of successful P3 trials....

Based on peak market value of $12B for CDX-011, you could then project that CDX-011 has a present value of $1.25B, or, with a current valuation for CLDX of $172M, that the market thinks that there is only a 14% chance that my scenario above becomes true. Either way, the likelihood that Celldex is undervalued is high.

(btw: is use the value of CLDX and CDX-011 interchangeably. While CLDX does have other products in the pipeline, 99% of CLDX valuation will depend on CDX-011.)

(CLDX says that 35% of breast cancer patients could benefit from targeting GPNMB with CDX-011. It's probably a rosy-case press release figure, but even if you chop this number in half, the resulting NPV for CDX-011 3.6X today's valuation.)


Factors for Celldex:
1) Few, if any, other GPNMB programs in existence, so it is a seller's market (when it comes to partnering) for Celldex.
2) There's plenty of reason to expect CLDX to partner CDX-011 soon, and it's an ideal time to partner - P3 trials costs are significant and therefore better shared with a partner, plus partnering now allows the Big Pharma partner to influence trial design.
3) CDX-011 clinical responses exceed the 30% hurdle rate and in P2B trials have a wide advantage versus the control arm. (I'm always skeptical if the response rate and advantage versus control group outcomes is <=20% and <=10%, respectively.)
4) Good sized market, not currently served.


Factors against Celldex:
1) small-cap biotechs NEVER successfully get drugs to the market by themselves.
2) ultimate FDA approval may be conditional for GPNMB+ only, and also could depend on the development of a gene-specific test.
3) lack of partner to date could represent Big Pharma skepticism over either GPNMB's target biology or Celldex's capabilities.
4) Limited ability to raise equity financing.
5) small sample size in P2B results.
6) time to FDA approval of ~2yrs limits the ability to buy call options for CLDX.

Ultimately, the value of CLDX is driven by 1) CDX's long term outlook, and 2) the size and timing of a partnership with a big pharma to commercialize CDX-011. Outlined above is one long-term scenario representing a win for CLDX, and for the other point (partnership value), I can easily see CLDX doubling the company's valuation this year after consumating a big pharma partnership centered on CDX-011. (Guess: $50M cash @ closing, $50M in equity purchased by the pharma partner, with $1B in milestones possible; also: $50M in easily achievable milestones to land in the first 12 months. (example: $25M payment at initiation of P3 trials.)

Here's hoping that CDX-011 lives up to the P2B results, and that finally we'll have a weapon against TNBC.


Disclosure: at the time of writing, I DO hold a tiny position in Celldex.

Exelixis: all-in on cabo

Luke Timmerman @ Xconomy has an excellent preview of ASCO - definitely worth a read.

What really surprised me in Luke's article is how leveraged Exelixis is on Cabozantinib ("Cabo"), with 9 Cabo presentations at ASCO addressing 7 tumor types. At this point, EXEL is a pure-play gamble on Cabo, with no other pipeline products close to the same maturity. If Cabo fails, so does EXEL.

From the Exelixis web site, here's the clinical status of Cabo trials:

ClinicalTrials.gov lists 19 open clinical trials involving Cabo.

Cabo (a.k.a. XL184) is a dual-selectivity tyrosine kinase inhibitor, targeting MET and VEGFR - two very relevant drug targets. (Please withhold snickering that dual selectivity may equal non-selectivity all you med chemists!) 

What makes Cabo potentially great is that it attacks cancers on multiple fronts, with anti-angiogenic activity (like Sutent) and anti-metastatic activity (by targeting MET.) EXEL also suggest that the compound is also cytotoxic ("tumoricidal") 

EXEL's financials look OK. Market valuation: $717M. Cash on hand: ~$240M, burning ~$14M/quarter on an operating basis, so there should be enough cash to fund the advancement of Cabo in multiple indications. One problem, though: it looks like EXEL some significant debt to repay, cutting into the cash hoard.

But most importantly, is Cabo any good? Here's what's posted at Wikipedia:

"Positive data from clinical trials indicate cabozantinib is particularly beneficial in metastatic advanced prostate cancer. 97% of patients either had stabilization or improvement in bone malignancies. The median time to disease progression was 29 weeks.^[2][3]

One US trial reported in May 2011 : The best results were seen in patients with liver, prostate, and ovarian cancer: 22 of 29 patients with liver cancer, 71 of 100 patients with prostate cancer, and 32 of 51 with ovarian cancer experienced either partial tumor shrinkage or stable disease. Fifty-nine out of 68 patients who had bone metastases had their metastases shrink or disappear during the trial.^[4]"

^{(And no, I don't use the Wikipedia to evaluate compounds, but it is a nice succinct summary.)}

But if Cabo is that good, how come BMS canceled their partnership over XL184 in 2010?

3 possible explanations:

1. Problems @ BMS

2. Problems @ EXEL

3. Inconclusive or weak early data.

There's an argument for each of these reasons. BMS withdrew from a partnership after only 2 years and having spent ~$250M on XL184. That should set off alarms, but EXEL pressed on, even with other products in the pipeline and after a leadership change at EXEL. Also, as of 2010, the most significant data was from a Phase II trial in a very small disease (MDT, still EXEL's lead application.)

Here's the EXEL investment risks as I see them, besides the standard cancer drug development & regulatory risks (i.e. traditional fractional rates of success at any given stage of development.) 

1. Cash/liquidity risk - as demonstrated by their early 2012 financing, there's not a lot of additional liquidity available to EXEL.

2. Timing: in spite of the broad clinical agenda, it might be years before Cabo would receive approval in some of its' most exciting indications (such as lung cancer, now in Phase II.)

3. Competition: a lot is happening in prostate cancer. Even with FDA approval in this area, could EXEL trump offerings in this area from big (JNJ) to small (Medivation)? (This might not be a risk, as interest in this area could spur a pharma partnership/acquisition.)

4. Commercialization risk: can a small company like EXEL successfully bring Cabo to market without a partner? (I don't think this is EXEL's strategy - they should partner immediately following ASCO, but it wouldn't surprise me if Big Pharma waited until data or FDA approval in a larger application became available.)

5. Skepticism due to both EXEL's track record to date, and standard small biotech caution - as Adam Feuerstein at TheStreet.com often points out, small, single product companies have a TERRIBLE FDA approval track record. 

6. (Update) Clinical trial design. Adam Feuerstein explains it best: history and competition suggest that approval in prostate cancer may be farther off than EXEL thinks.

On the other hand, here's the positives:

1. Upside. If FDA approved for even half of its' intended applications, Cabo would have peak revenues in the $1B-$2B range, equating to equity value of $3B-$12B. (EXEL's current enterprise value is ~$500M, equating to a 6X to 24X return, though this could be inhibited or perhaps amplified by a partnership with a Big Pharma. If an investment is made via call options, the leveraged return could be again boosted by 10X.)

2. No target biology risk - both MET and VEGFR2 are well known oncology targets, with clinical success. (Though I can't think of an approved MET inhibitor right now. Arqule's is in P2, I think.)

3. Negligible downside. (OK, not really a positive.)

4. Pipeline value: it's pretty clear that the market is not valuing the rest of EXEL's pipeline. One reason for this is the notion that EXEL is all-in on Cabo to the exclusion of the rest of the pipeline (which is true), but there are enough interesting early leads in the pipeline that any of these could eventually be partnered to unlock value.

5. Compound de-risking. Clinical efforts in so many different indications suggests that 1) there is an abundance of positive health, safety, and efficacy data, and 2) either the management team is suicidal, or has good reason to bet the company on Cabo.

Ultimately, I think EXEL is at an inflection point with their appearance at ASCO - if the data in one or more indications for Cabo is compelling, a pharma partnership in 2012 is likely, which would boost value and decrease risk. If no pharma partners emerge, that's a strong statement that Pharma is still skeptical about Cabo, because pharma desperately needs to add to its' pipeline. (I am ignoring the possibility that EXEL management might value Cabo too highly to partner - they need to do a deal ASAP, or they will lack the resources to bring Cabo to market and the Street will lose faith in EXEL.)

(I could be wrong, as EXEL stock barely moved with last weeks publication of the ASCO abstracts.)

So, EXEL is a high-leverage biotech casino, with a high likelihood of either complete boom or complete bust. I kinda wish more small-caps would take the same approach with their development efforts (all-in!) Of course, it is easy to say this as an outsider - investors can hedge risk in other ways - but for EXEL employees and management, there's no way to hedge an all-in bet.

btw: another company with a lot riding on ASCO is Onyx, which I reviewed last month.

Bonus idea: for being so leveraged to Cabo, shouldn't EXEL change their name to "The Cabo Co." and their stock ticker to CABO? Who knows, maybe they'd attract some investors thinking that CABO is a Mexican real estate portfolio.

Disclosure: as of the time of writing, I own NO shares of EXEL.

ONYX under the microscope

Related to FierceBiotech's Top 10 Promising Cancer Drugs mentioned in my last post, there's one company with two drug candidates in the Top 10 - Onyx Pharma (ONXX).

Each Onyx program is reaching an important milestone/inflection point over the next year, making this an interesting year for the stock, which makes it worth putting under the microscope.

First a refresher: ONXX has an enterprise value of $2B, largely based on Nexavar, their FDA-approved small molecule multi-TK inhibitor. (Inhibiting VEGFR, PDGFR, and Raf, and approved for RCC and HCC.) What makes Nexavar unique is that it is the only approved MAPK inhibitor. (Indeed the only survivor from very intense pharma R&D over the last 15 years.)) Nexavar sales totaled $1B in 2011, and grew 8%. ONXX stock is up 20% over the last 12 months (vs. 10% for NAS), but at 57% vs 81%, ONXX lags the NAS over the last three years.

(live link to chart.)

The partnership between Bayer and Onyx is a bit messy accounting-wise (and was very messy in every other way until last fall), but a half-interest in a growing billion dollar drug is probably worth ~$1.25B. (Quick n' dirty: 50% of $1B in annual rev * 2.5X average price to sales ratio for pharma industry.)

2012: this year Onyx might transform from a company with a single product for two disease indications to a company with three products for five disease indications based on developments in the two programs highlighted by FierceBiotech - Regorafenib for CRC and GIST (CRC is a big market, GIST is small), and Carfilzomib for multiple myeloma (huge market, with Velcade (Millennium) and Revlimid (Celgene) together accounting for >$4B in multiple myeloma drug sales.)

Regorafenib is an interesting story. Regorafenib is very similar to Nexavar, but Onyx's partner Bayer developed the drug on their own. Both sides wrestled over the IP, but eventually settled with Bayer sharing a 20% royalty to ONXX on Regorafenib. I am guessing the amended partnership agreement also included an agreement to market the two similar drugs at different markets, as Regorafenib is seeking approval in new markets relative to Nexavar.

An FDA decision on Carfilzomib will be announced before August, while Regorafenib will file for approval with the FDA later this year. (But with approval in 2013?). Both drugs have supportive late stage trial data.

So, what's ONXX worth? 

The sum of:

value of their interest in Nexavar + value of their 20% interest in Regorafenib, adjusted by the probability of FDA approval + value of Carfilzomib, adjusted by the probability of FDA approval.

here's the exciting part: the sum of the above is MULTIPLIED BY AN ACQUISITION PREMIUM, ADJUSTED FOR THE PROBABILITY OF A BIG PHARMA BUYING ONXX.

(Acquisition rationale: 1) pharmas buy growth products, 2) pharmas buy blockbusters, and 3) Bayer in particular is likely to want to buy out their partner.)

If everything was FDA approved, I think ONXX would be worth roughly

$1.25B for Nexavar

$500M for their 20% interest in Regorafenib (at $1B peak sales x 2.5 P/S ratio).

$2.5B for Carfilzomib (also $1B peak sales x 2.5 P/S ratio. $1B in revenue at peak assumes ONXX takes 25% of the $4B multiple myeloma market, likely displacing Millennium, not Celgene.)

Operating value total: $4.25B

Adding a modest 25% acquisition premium assumption would yield a predicted future value of ONXX of $5.3B, or 2.65X the current enterprise valuation.

(technically you'd discount back from the period of peak sales for each drug for it's present value, but let's keep things simple.)

The expectations for ONXX's prompt FDA approvals obviously would change (reduce) the final corporate valuation a great amount. I have absolutely no insight into what ONXX's chances are with the FDA, nor do I have any reason to make a prediction of ONXX's probability of prompt approval, so you need to adjust the ONXX valuation by your own expectations. But, another way you could look at ONXX is to infer the market's expectations of FDA and product success from today's valuation.

If ONXX's enterprise value is ~$2B, and Nexavar is "worth" $1.25B, you could infer that the discounted value of Carfilzomib + Regorafenib totals $750M. (I'm simplifying here - this analysis assumes no future value for anything else in ONXX's pipeline, which isn't fair.) By extension then, the market says that there is a 18% probability (750/($5.3B-1.25B)) of the scenario I outlined above, including acquisition of ONXX at a premium.

It's up to you to add your own perspective - this is not a recommendation to buy or sell ONXX stock. As of this writing, I hold no ONXX shares and can state definitively that this will not change over the rest of the week. If/when my disposition changes, I will update this page.

Please let me know in the comments section what you think of the above "under the microscope" analysis, and if you would be interested in my duplicating it with other bio-pharma companies in the future.